Merge pull request #18332 from Ondsel-Development/core_LCS3

Core Datums: Card4 : implement part subclasses.

src/App/Datums.cpp

@@ -3,22 +3,21 @@
  *   Copyright (c) 2015 Alexander Golubev (Fat-Zer) <fatzer2@gmail.com>    *
  *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
  *                                                                         *
- *   This file is part of the FreeCAD CAx development system.              *
+ *   This file is part of FreeCAD.                                         *
  *                                                                         *
- *   This library is free software; you can redistribute it and/or         *
- *   modify it under the terms of the GNU Library General Public           *
- *   License as published by the Free Software Foundation; either          *
- *   version 2 of the License, or (at your option) any later version.      *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
  *                                                                         *
- *   This library  is distributed in the hope that it will be useful,      *
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
- *   GNU Library General Public License for more details.                  *
+ *   FreeCAD is distributed in the hope that it will be useful, but        *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   Lesser General Public License for more details.                       *
  *                                                                         *
- *   You should have received a copy of the GNU Library General Public     *
- *   License along with this library; see the file COPYING.LIB. If not,    *
- *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
- *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
  *                                                                         *
  ***************************************************************************/
 
@@ -207,9 +206,9 @@ const std::vector<LocalCoordinateSystem::SetupData>& LocalCoordinateSystem::getS
 {
     static const std::vector<SetupData> setupData = {
         // clang-format off
-        {App::Line::getClassTypeId(),  AxisRoles[0],  tr("X-axis"),   Base::Rotation()},
-        {App::Line::getClassTypeId(),  AxisRoles[1],  tr("Y-axis"),   Base::Rotation(Base::Vector3d(1, 1, 1), M_PI * 2 / 3)},
-        {App::Line::getClassTypeId(),  AxisRoles[2],  tr("Z-axis"),   Base::Rotation(Base::Vector3d(1,-1, 1), M_PI * 2 / 3)},
+        {App::Line::getClassTypeId(),  AxisRoles[0],  tr("X-axis"),   Base::Rotation(Base::Vector3d(1, 1, 1), M_PI * 2 / 3)},
+        {App::Line::getClassTypeId(),  AxisRoles[1],  tr("Y-axis"),   Base::Rotation(Base::Vector3d(-1, 1, 1), M_PI * 2 / 3)},
+        {App::Line::getClassTypeId(),  AxisRoles[2],  tr("Z-axis"),   Base::Rotation()},
         {App::Plane::getClassTypeId(), PlaneRoles[0], tr("XY-plane"), Base::Rotation()},
         {App::Plane::getClassTypeId(), PlaneRoles[1], tr("XZ-plane"), Base::Rotation(1.0, 0.0, 0.0, 1.0)},
         {App::Plane::getClassTypeId(), PlaneRoles[2], tr("YZ-plane"), Base::Rotation(Base::Vector3d(1, 1, 1), M_PI * 2 / 3)},
@@ -277,6 +276,56 @@ void LocalCoordinateSystem::unsetupObject()
     }
 }
 
+void LocalCoordinateSystem::onDocumentRestored()
+{
+    GeoFeature::onDocumentRestored();
+
+    // In 0.22 origins did not have point.
+    migrateOriginPoint();
+
+    // In 0.22 the axis placement were wrong. The X axis had identity placement instead of the Z.
+    // This was fixed but we need to migrate old files.
+    migrateXAxisPlacement();
+}
+
+void LocalCoordinateSystem::migrateOriginPoint()
+{
+    auto features = OriginFeatures.getValues();
+
+    auto isOrigin = [](App::DocumentObject* obj) {
+        return obj->isDerivedFrom<App::DatumElement>() &&
+            strcmp(static_cast<App::DatumElement*>(obj)->Role.getValue(), PointRoles[0]) == 0;
+    };
+    if (std::none_of(features.begin(), features.end(), isOrigin)) {
+        auto data = getData(PointRoles[0]);
+        auto* origin = createDatum(data);
+        features.push_back(origin);
+        OriginFeatures.setValues(features);
+    }
+}
+
+void LocalCoordinateSystem::migrateXAxisPlacement()
+{
+    auto features = OriginFeatures.getValues();
+
+    migrated = false;
+
+    const auto& setupData = getSetupData();
+    for (auto* obj : features) {
+        auto* feature = dynamic_cast <App::DatumElement*> (obj);
+        if (!feature) { continue; }
+        for (auto data : setupData) {
+            // ensure the rotation is correct for the role
+            if (std::strcmp(feature->Role.getValue(), data.role) == 0) {
+                if (!feature->Placement.getValue().getRotation().isSame(data.rot)) {
+                    feature->Placement.setValue(Base::Placement(Base::Vector3d(), data.rot));
+                    migrated = true;
+                }
+            }
+        }
+    }
+}
+
 // ----------------------------------------------------------------------------
 
 LocalCoordinateSystem::LCSExtension::LCSExtension(LocalCoordinateSystem* obj)

src/App/Datums.h

@@ -3,22 +3,21 @@
  *   Copyright (c) 2015 Alexander Golubev (Fat-Zer) <fatzer2@gmail.com>    *
  *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
  *                                                                         *
- *   This file is part of the FreeCAD CAx development system.              *
+ *   This file is part of FreeCAD.                                         *
  *                                                                         *
- *   This library is free software; you can redistribute it and/or         *
- *   modify it under the terms of the GNU Library General Public           *
- *   License as published by the Free Software Foundation; either          *
- *   version 2 of the License, or (at your option) any later version.      *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
  *                                                                         *
- *   This library  is distributed in the hope that it will be useful,      *
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
- *   GNU Library General Public License for more details.                  *
+ *   FreeCAD is distributed in the hope that it will be useful, but        *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   Lesser General Public License for more details.                       *
  *                                                                         *
- *   You should have received a copy of the GNU Library General Public     *
- *   License along with this library; see the file COPYING.LIB. If not,    *
- *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
- *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
  *                                                                         *
  ***************************************************************************/
 
@@ -206,6 +205,8 @@ public:
     // Axis links
     PropertyLinkList OriginFeatures;
 
+    bool migrated;
+
 protected:
     /// Checks integrity of the LCS
     App::DocumentObjectExecReturn* execute() override;
@@ -213,6 +214,7 @@ protected:
     void setupObject() override;
     /// Removes all planes and axis if they are still linked to the document
     void unsetupObject() override;
+    void onDocumentRestored() override;
 
 private:
     struct SetupData;
@@ -245,6 +247,9 @@ private:
 
     DatumElement* createDatum(SetupData& data);
     SetupData getData(const char* role);
+
+    void migrateOriginPoint();
+    void migrateXAxisPlacement();
 };
 
 }  // namespace App

src/App/GeoFeature.cpp

@@ -134,7 +134,7 @@ ElementNamePair GeoFeature::_getElementName(const char* name,
     }
 }
 
-DocumentObject* GeoFeature::resolveElement(DocumentObject* obj,
+DocumentObject* GeoFeature::resolveElement(const DocumentObject* obj,
                                            const char* subname,
                                            ElementNamePair& elementName,
                                            bool append,

src/App/GeoFeature.h

@@ -104,7 +104,7 @@ public:
      *
      * @return Return the owner object of the element
      */
-    static DocumentObject* resolveElement(App::DocumentObject* obj,
+    static DocumentObject* resolveElement(const App::DocumentObject* obj,
                                           const char* subname,
                                           ElementNamePair& elementName,
                                           bool append = false,

src/Gui/CommandStructure.cpp

@@ -156,9 +156,9 @@ void StdCmdVarSet::activated(int iMsg)
 
     // add the varset to a group if it is selected
     auto sels = Selection().getSelectionEx(nullptr, App::DocumentObject::getClassTypeId(),
-                                           ResolveMode::OldStyleElement, true);
+        ResolveMode::OldStyleElement, true);
     if (sels.size() == 1) {
-        App::DocumentObject *obj = sels[0].getObject();
+        App::DocumentObject* obj = sels[0].getObject();
         auto group = obj->getExtension<App::GroupExtension>();
         if (group) {
             Gui::Document* docGui = Application::Instance->activeDocument();

src/Gui/ViewProviderCoordinateSystem.cpp

@@ -26,6 +26,8 @@
 #ifndef _PreComp_
 # include <Inventor/nodes/SoLightModel.h>
 # include <Inventor/nodes/SoSeparator.h>
+# include <QMessageBox>
+# include <QCheckBox>
 #endif
 
 #include <App/Document.h>
@@ -83,6 +85,50 @@ void ViewProviderCoordinateSystem::attach(App::DocumentObject* pcObject)
     addDisplayMaskMode(pcGroupChildren, "Base");
 }
 
+void ViewProviderCoordinateSystem::finishRestoring()
+{
+    showMigrationDialog();
+}
+
+void ViewProviderCoordinateSystem::showMigrationDialog()
+{
+    auto lcs = dynamic_cast<App::LocalCoordinateSystem*>(getObject());
+    if (!lcs || !lcs->migrated) {
+        return;
+    }
+
+    static bool userWarned = false;
+
+    if (userWarned || !App::GetApplication().GetParameterGroupByPath(
+        "User parameter:BaseApp/Preferences/View")->GetBool("ShowLCSMigrationWarning", true)) {
+        return;
+    }
+
+    // Display the warning message
+    QMessageBox msgBox(QMessageBox::Warning,
+        QObject::tr("File Migration Warning"),
+        QObject::tr("This file was created with an older version of FreeCAD. "
+            "Origin axes had incorrect placements, which have now been corrected.\n\n"
+            "However, if you save this file in the current version and reopen it in an"
+            " older version of FreeCAD, the origin axes will be misaligned. Additionally, "
+            "if your file references these origin axes, your file will likely be broken."),
+        QMessageBox::Ok);
+
+    QCheckBox* checkBox = new QCheckBox(QObject::tr("Don't show this warning again"));
+    msgBox.setCheckBox(checkBox);
+
+    msgBox.exec();
+
+    // Update static flag if the user has seen the warning
+    userWarned = true;
+
+    // Save preference if the user selects "Don't show again"
+    if (checkBox->isChecked()) {
+        App::GetApplication().GetParameterGroupByPath(
+            "User parameter:BaseApp/Preferences/View")->SetBool("ShowLCSMigrationWarning", false);
+    }
+}
+
 std::vector<std::string> ViewProviderCoordinateSystem::getDisplayModes() const
 {
     return { "Base" };

src/Gui/ViewProviderCoordinateSystem.h

@@ -83,7 +83,11 @@ protected:
     void updateData(const App::Property*) override;
     bool onDelete(const std::vector<std::string> &) override;
 
+    void finishRestoring() override;
+
 private:
+    void showMigrationDialog();
+
     SoGroup *pcGroupChildren;
 
     std::map<Gui::ViewProvider*, bool> tempVisMap;

src/Gui/ViewProviderLine.cpp

@@ -83,12 +83,12 @@ void ViewProviderLine::attach(App::DocumentObject *obj) {
 
     SbVec3f verts[2];
     if (noRole) {
-        verts[0] = SbVec3f(2 * size, 0, 0);
+        verts[0] = SbVec3f(0, 0, 2 * size);
         verts[1] = SbVec3f(0, 0, 0);
     }
     else {
-        verts[0] = SbVec3f(size, 0, 0);
-        verts[1] = SbVec3f(0.2 * size, 0, 0);
+        verts[0] = SbVec3f(0, 0, size);
+        verts[1] = SbVec3f(0, 0, 0.2 * size);
     }
 
     // indexes used to create the edges
@@ -107,7 +107,7 @@ void ViewProviderLine::attach(App::DocumentObject *obj) {
     sep->addChild ( pLines );
 
     auto textTranslation = new SoTranslation ();
-    textTranslation->translation.setValue ( SbVec3f ( size * 1.1, 0, 0 ) );
+    textTranslation->translation.setValue(SbVec3f(0, 0, size * 1.1));
     sep->addChild ( textTranslation );
 
     auto ps = new SoPickStyle();

src/Mod/Assembly/App/AssemblyObject.cpp

@@ -33,6 +33,7 @@
 #include <chrono>
 
 #include <App/Application.h>
+#include <App/Datums.h>
 #include <App/Document.h>
 #include <App/DocumentObjectGroup.h>
 #include <App/FeaturePythonPyImp.h>
@@ -45,6 +46,7 @@
 #include <Base/Interpreter.h>
 
 #include <Mod/Part/App/TopoShape.h>
+#include <Mod/Part/App/AttachExtension.h>
 
 #include <OndselSolver/CREATE.h>
 #include <OndselSolver/ASMTSimulationParameters.h>
@@ -93,6 +95,10 @@ FC_LOG_LEVEL_INIT("Assembly", true, true, true)
 using namespace Assembly;
 using namespace MbD;
 
+
+namespace PartApp = Part;
+
+
 // ================================ Assembly Object ============================
 
 PROPERTY_SOURCE(Assembly::AssemblyObject, App::Part)
@@ -135,7 +141,7 @@ int AssemblyObject::solve(bool enableRedo, bool updateJCS)
     objectPartMap.clear();
     motions.clear();
 
-    std::vector<App::DocumentObject*> groundedObjs = fixGroundedParts();
+    auto groundedObjs = fixGroundedParts();
     if (groundedObjs.empty()) {
         // If no part fixed we can't solve.
         return -6;
@@ -178,7 +184,7 @@ int AssemblyObject::generateSimulation(App::DocumentObject* sim)
 
     motions = getMotionsFromSimulation(sim);
 
-    std::vector<App::DocumentObject*> groundedObjs = fixGroundedParts();
+    auto groundedObjs = fixGroundedParts();
     if (groundedObjs.empty()) {
         // If no part fixed we can't solve.
         return -6;
@@ -351,7 +357,8 @@ Base::Placement AssemblyObject::getMbdPlacement(std::shared_ptr<ASMTPart> mbdPar
 bool AssemblyObject::validateNewPlacements()
 {
     // First we check if a grounded object has moved. It can happen that they flip.
-    for (auto* obj : getGroundedParts()) {
+    auto groundedParts = getGroundedParts();
+    for (auto* obj : groundedParts) {
         auto* propPlacement =
             dynamic_cast<App::PropertyPlacement*>(obj->getPropertyByName("Placement"));
         if (propPlacement) {
@@ -367,7 +374,8 @@ bool AssemblyObject::validateNewPlacements()
 
                 if (!oldPlc.isSame(newPlacement)) {
                     Base::Console().Warning(
-                        "Assembly : Ignoring bad solve, a grounded object moved.\n");
+                        "Assembly : Ignoring bad solve, a grounded object (%s) moved.\n",
+                        obj->getFullLabel());
                     return false;
                 }
             }
@@ -749,11 +757,11 @@ std::vector<App::DocumentObject*> AssemblyObject::getJointsOfPart(App::DocumentO
     return jointsOf;
 }
 
-std::vector<App::DocumentObject*> AssemblyObject::getGroundedParts()
+std::unordered_set<App::DocumentObject*> AssemblyObject::getGroundedParts()
 {
     std::vector<App::DocumentObject*> groundedJoints = getGroundedJoints();
 
-    std::vector<App::DocumentObject*> groundedObjs;
+    std::unordered_set<App::DocumentObject*> groundedSet;
     for (auto gJoint : groundedJoints) {
         if (!gJoint) {
             continue;
@@ -764,34 +772,49 @@ std::vector<App::DocumentObject*> AssemblyObject::getGroundedParts()
 
         if (propObj) {
             App::DocumentObject* objToGround = propObj->getValue();
-            groundedObjs.push_back(objToGround);
+            if (objToGround) {
+                groundedSet.insert(objToGround);
+            }
         }
     }
-    return groundedObjs;
+
+    // We also need to add all the root-level datums objects that are not attached.
+    std::vector<App::DocumentObject*> objs = Group.getValues();
+    for (auto* obj : objs) {
+        if (obj->isDerivedFrom<App::LocalCoordinateSystem>()
+            || obj->isDerivedFrom<App::DatumElement>()) {
+            auto* pcAttach = obj->getExtensionByType<PartApp::AttachExtension>();
+            if (pcAttach) {
+                // If it's a Part datums, we check if it's attached. If yes then we ignore it.
+                std::string mode = pcAttach->MapMode.getValueAsString();
+                if (mode != "Deactivated") {
+                    continue;
+                }
+            }
+            groundedSet.insert(obj);
+        }
+    }
+
+    // Origin is not in Group so we add it separately
+    groundedSet.insert(Origin.getValue());
+
+    return groundedSet;
 }
 
-std::vector<App::DocumentObject*> AssemblyObject::fixGroundedParts()
+std::unordered_set<App::DocumentObject*> AssemblyObject::fixGroundedParts()
 {
-    std::vector<App::DocumentObject*> groundedJoints = getGroundedJoints();
+    auto groundedParts = getGroundedParts();
 
-    std::vector<App::DocumentObject*> groundedObjs;
-    for (auto obj : groundedJoints) {
+    for (auto obj : groundedParts) {
         if (!obj) {
             continue;
         }
 
-        auto* propObj = dynamic_cast<App::PropertyLink*>(obj->getPropertyByName("ObjectToGround"));
-
-        if (propObj) {
-            App::DocumentObject* objToGround = propObj->getValue();
-
-            Base::Placement plc = getPlacementFromProp(obj, "Placement");
-            std::string str = obj->getFullName();
-            fixGroundedPart(objToGround, plc, str);
-            groundedObjs.push_back(objToGround);
-        }
+        Base::Placement plc = getPlacementFromProp(obj, "Placement");
+        std::string str = obj->getFullName();
+        fixGroundedPart(obj, plc, str);
     }
-    return groundedObjs;
+    return groundedParts;
 }
 
 void AssemblyObject::fixGroundedPart(App::DocumentObject* obj,
@@ -902,7 +925,7 @@ bool AssemblyObject::isObjInSetOfObjRefs(App::DocumentObject* obj, const std::ve
 }
 
 void AssemblyObject::removeUnconnectedJoints(std::vector<App::DocumentObject*>& joints,
-                                             std::vector<App::DocumentObject*> groundedObjs)
+                                             std::unordered_set<App::DocumentObject*> groundedObjs)
 {
     std::vector<ObjRef> connectedParts;
 
@@ -994,7 +1017,7 @@ bool AssemblyObject::isPartGrounded(App::DocumentObject* obj)
         return false;
     }
 
-    std::vector<App::DocumentObject*> groundedObjs = getGroundedParts();
+    auto groundedObjs = getGroundedParts();
 
     for (auto* groundedObj : groundedObjs) {
         if (groundedObj->getFullName() == obj->getFullName()) {
@@ -1011,7 +1034,7 @@ bool AssemblyObject::isPartConnected(App::DocumentObject* obj)
         return false;
     }
 
-    std::vector<App::DocumentObject*> groundedObjs = getGroundedParts();
+    auto groundedObjs = getGroundedParts();
     std::vector<App::DocumentObject*> joints = getJoints(false);
 
     std::vector<ObjRef> connectedParts;
@@ -1958,29 +1981,6 @@ std::vector<AssemblyLink*> AssemblyObject::getSubAssemblies()
     return subAssemblies;
 }
 
-void AssemblyObject::updateGroundedJointsPlacements()
-{
-    std::vector<App::DocumentObject*> groundedJoints = getGroundedJoints();
-
-    for (auto gJoint : groundedJoints) {
-        if (!gJoint) {
-            continue;
-        }
-
-        auto* propObj =
-            dynamic_cast<App::PropertyLink*>(gJoint->getPropertyByName("ObjectToGround"));
-        auto* propPlc =
-            dynamic_cast<App::PropertyPlacement*>(gJoint->getPropertyByName("Placement"));
-
-        if (propObj && propPlc) {
-            App::DocumentObject* obj = propObj->getValue();
-            auto* propObjPlc =
-                dynamic_cast<App::PropertyPlacement*>(obj->getPropertyByName("Placement"));
-            propPlc->setValue(propObjPlc->getValue());
-        }
-    }
-}
-
 void AssemblyObject::ensureIdentityPlacements()
 {
     std::vector<App::DocumentObject*> group = Group.getValues();
@@ -2011,36 +2011,3 @@ void AssemblyObject::ensureIdentityPlacements()
         }
     }
 }
-
-/*void Part::handleChangedPropertyType(Base::XMLReader& reader, const char* TypeName, App::Property*
-prop)
-{
-    App::Part::handleChangedPropertyType(reader, TypeName, prop);
-}*/
-
-/* Apparently not necessary as App::Part doesn't have this.
-// Python Assembly feature ---------------------------------------------------------
-
-namespace App
-{
-    /// @cond DOXERR
-    PROPERTY_SOURCE_TEMPLATE(Assembly::AssemblyObjectPython, Assembly::AssemblyObject)
-        template<>
-    const char* Assembly::AssemblyObjectPython::getViewProviderName() const
-    {
-        return "AssemblyGui::ViewProviderAssembly";
-    }
-    template<>
-    PyObject* Assembly::AssemblyObjectPython::getPyObject()
-    {
-        if (PythonObject.is(Py::_None())) {
-            // ref counter is set to 1
-            PythonObject = Py::Object(new FeaturePythonPyT<AssemblyObjectPy>(this), true);
-        }
-        return Py::new_reference_to(PythonObject);
-    }
-    /// @endcond
-
-    // explicit template instantiation
-    template class AssemblyExport FeaturePythonT<Assembly::AssemblyObject>;
-}// namespace App*/

src/Mod/Assembly/App/AssemblyObject.h

@@ -157,8 +157,8 @@ public:
     std::vector<App::DocumentObject*> getJointsOfPart(App::DocumentObject* part);
     App::DocumentObject* getJointOfPartConnectingToGround(App::DocumentObject* part,
                                                           std::string& name);
-    std::vector<App::DocumentObject*> getGroundedParts();
-    std::vector<App::DocumentObject*> fixGroundedParts();
+    std::unordered_set<App::DocumentObject*> getGroundedParts();
+    std::unordered_set<App::DocumentObject*> fixGroundedParts();
     void fixGroundedPart(App::DocumentObject* obj, Base::Placement& plc, std::string& jointName);
 
     bool isJointConnectingPartToGround(App::DocumentObject* joint, const char* partPropName);
@@ -166,7 +166,7 @@ public:
 
     bool isObjInSetOfObjRefs(App::DocumentObject* obj, const std::vector<ObjRef>& pairs);
     void removeUnconnectedJoints(std::vector<App::DocumentObject*>& joints,
-                                 std::vector<App::DocumentObject*> groundedObjs);
+                                 std::unordered_set<App::DocumentObject*> groundedObjs);
     void traverseAndMarkConnectedParts(App::DocumentObject* currentPart,
                                        std::vector<ObjRef>& connectedParts,
                                        const std::vector<App::DocumentObject*>& joints);
@@ -186,7 +186,6 @@ public:
     void setObjMasses(std::vector<std::pair<App::DocumentObject*, double>> objectMasses);
 
     std::vector<AssemblyLink*> getSubAssemblies();
-    void updateGroundedJointsPlacements();
 
     std::vector<App::DocumentObject*> getMotionsFromSimulation(App::DocumentObject* sim);
 

src/Mod/Assembly/App/AssemblyUtils.cpp

@@ -33,6 +33,7 @@
 #endif
 
 #include <App/Application.h>
+#include <App/Datums.h>
 #include <App/Document.h>
 #include <App/DocumentObject.h>
 #include <App/PropertyStandard.h>
@@ -536,7 +537,9 @@ App::DocumentObject* getObjFromRef(const App::DocumentObject* obj, const std::st
         // getViewProviderName instead of isDerivedFrom to avoid dependency on sketcher
         const auto isDerivedFromVpSketch =
             strcmp(obj->getViewProviderName(), "SketcherGui::ViewProviderSketch") == 0;
-        return isDerivedFromVpSketch || obj->isDerivedFrom<PartApp::Datum>();
+        return isDerivedFromVpSketch || obj->isDerivedFrom<PartApp::Datum>()
+            || obj->isDerivedFrom<App::DatumElement>()
+            || obj->isDerivedFrom<App::LocalCoordinateSystem>();
     };
 
     // Helper function to handle PartDesign::Body objects

src/Mod/Assembly/CommandCreateJoint.py

@@ -47,11 +47,7 @@ def noOtherTaskActive():
 
 
 def isCreateJointActive():
-    return (
-        UtilsAssembly.isAssemblyGrounded()
-        and UtilsAssembly.assembly_has_at_least_n_parts(2)
-        and noOtherTaskActive()
-    )
+    return UtilsAssembly.assembly_has_at_least_n_parts(1) and noOtherTaskActive()
 
 
 def activateJoint(index):

src/Mod/Assembly/Gui/ViewProviderAssembly.cpp

@@ -229,12 +229,6 @@ bool ViewProviderAssembly::setEdit(int mode)
                                 PARTKEY,
                                 this->getObject()->getNameInDocument());
 
-        // When we set edit, we update the grounded joints placements to support :
-        // - If user transformed the grounded object
-        // - For nested assemblies where the grounded object moves around.
-        auto* assembly = getObject<AssemblyObject>();
-        assembly->updateGroundedJointsPlacements();
-
         setDragger();
 
         attachSelection();

src/Mod/Assembly/JointObject.py

@@ -956,18 +956,6 @@ class GroundedJoint:
 
         joint.ObjectToGround = obj_to_ground
 
-        joint.addProperty(
-            "App::PropertyPlacement",
-            "Placement",
-            "Ground",
-            QT_TRANSLATE_NOOP(
-                "App::Property",
-                "This is where the part is grounded.",
-            ),
-        )
-
-        joint.Placement = obj_to_ground.Placement
-
     def dumps(self):
         return None
 
@@ -1160,24 +1148,33 @@ class MakeJointSelGate:
             return False
 
         ref = [obj, [sub]]
-        selected_object = UtilsAssembly.getObject(ref)
+        sel_obj = UtilsAssembly.getObject(ref)
 
-        if not (
-            selected_object.isDerivedFrom("Part::Feature")
-            or selected_object.isDerivedFrom("App::Part")
+        if UtilsAssembly.isLink(sel_obj):
+            linked = sel_obj.getLinkedObject()
+            if linked == sel_obj:
+                return True  # We accept empty links
+            sel_obj = linked
+
+        if sel_obj.isDerivedFrom("Part::Feature") or sel_obj.isDerivedFrom("App::Part"):
+            return True
+
+        if sel_obj.isDerivedFrom("App::LocalCoordinateSystem") or sel_obj.isDerivedFrom(
+            "App::DatumElement"
         ):
-            if UtilsAssembly.isLink(selected_object):
-                linked = selected_object.getLinkedObject()
-                if linked == selected_object:
-                    # We accept empty links
-                    return True
+            datum = sel_obj
+            if datum.isDerivedFrom("App::DatumElement"):
+                parent = datum.getParent()
+                if parent.isDerivedFrom("App::LocalCoordinateSystem"):
+                    datum = parent
 
-                if not (linked.isDerivedFrom("Part::Feature") or linked.isDerivedFrom("App::Part")):
-                    return False
-            else:
-                return False
+            if self.assembly.hasObject(datum) and hasattr(datum, "MapMode"):
+                # accept only datum that are not attached
+                return datum.MapMode == "Deactivated"
 
-        return True
+            return True
+
+        return False
 
 
 activeTask = None

src/Mod/Assembly/UtilsAssembly.py

@@ -161,6 +161,21 @@ def getObject(ref):
         if obj.TypeId in {"App::Part", "Assembly::AssemblyObject"} or isLinkGroup(obj):
             continue
 
+        elif obj.isDerivedFrom("App::LocalCoordinateSystem"):
+            # 2 cases possible, either we have the LCS itself: "part.LCS."
+            # or we have a datum: "part.LCS.X_Axis"
+            if i + 1 < len(names):
+                obj2 = None
+                for obji in obj.OutList:
+                    if obji.Name == names[i + 1]:
+                        obj2 = obji
+                        break
+                if obj2 and obj2.isDerivedFrom("App::DatumElement"):
+                    return obj2
+
+        elif obj.isDerivedFrom("App::DatumElement"):
+            return obj
+
         elif obj.TypeId == "PartDesign::Body":
             if i + 1 < len(names):
                 obj2 = None
@@ -168,7 +183,7 @@ def getObject(ref):
                     if obji.Name == names[i + 1]:
                         obj2 = obji
                         break
-                if obj2 and isBodySubObject(obj2.TypeId):
+                if obj2 and isBodySubObject(obj2):
                     return obj2
             return obj
 
@@ -185,7 +200,7 @@ def getObject(ref):
                         if obji.Name == names[i + 1]:
                             obj2 = obji
                             break
-                    if obj2 and isBodySubObject(obj2.TypeId):
+                    if obj2 and isBodySubObject(obj2):
                         return obj2
                 return obj
             elif linked_obj.isDerivedFrom("Part::Feature"):
@@ -197,13 +212,12 @@ def getObject(ref):
     return None
 
 
-def isBodySubObject(typeId):
+def isBodySubObject(obj):
     return (
-        typeId == "Sketcher::SketchObject"
-        or typeId == "PartDesign::Point"
-        or typeId == "PartDesign::Line"
-        or typeId == "PartDesign::Plane"
-        or typeId == "PartDesign::CoordinateSystem"
+        obj.isDerivedFrom("Sketcher::SketchObject")
+        or obj.isDerivedFrom("PartDesign::Datum")
+        or obj.isDerivedFrom("App::DatumElement")
+        or obj.isDerivedFrom("App::LocalCoordinateSystem")
     )
 
 
@@ -348,21 +362,6 @@ def getElementName(full_name):
     if parts[-1] in {"X", "Y", "Z", "Point", "Line", "Plane"}:
         return ""
 
-    # Case of origin objects
-    if parts[-1] == "":
-        if "X_Axis" in parts[-2]:
-            return "X_Axis"
-        if "Y_Axis" in parts[-2]:
-            return "Y_Axis"
-        if "Z_Axis" in parts[-2]:
-            return "Z_Axis"
-        if "XY_Plane" in parts[-2]:
-            return "XY_Plane"
-        if "XZ_Plane" in parts[-2]:
-            return "XZ_Plane"
-        if "YZ_Plane" in parts[-2]:
-            return "YZ_Plane"
-
     return parts[-1]
 
 
@@ -946,16 +945,8 @@ def findPlacement(ref, ignoreVertex=False):
     elt = getElementName(ref[1][0])
     vtx = getElementName(ref[1][1])
 
-    # case of origin objects.
-    if elt == "X_Axis" or elt == "YZ_Plane":
-        return App.Placement(App.Vector(), App.Rotation(App.Vector(0, 1, 0), -90))
-    if elt == "Y_Axis" or elt == "XZ_Plane":
-        return App.Placement(App.Vector(), App.Rotation(App.Vector(1, 0, 0), 90))
-    if elt == "Z_Axis" or elt == "XY_Plane":
-        return App.Placement()
-
     if not elt or not vtx:
-        # case of whole parts such as PartDesign::Body or PartDesign::CordinateSystem/Point/Line/Plane.
+        # case of whole parts such as PartDesign::Body or App/PartDesign::CordinateSystem/Point/Line/Plane.
         return App.Placement()
 
     plc = App.Placement()

src/Mod/Part/App/AppPart.cpp

@@ -58,6 +58,7 @@
 #include "ConicPy.h"
 #include "CustomFeature.h"
 #include "CylinderPy.h"
+#include "Datums.h"
 #include "DatumFeature.h"
 #include "EllipsePy.h"
 #include "FaceMaker.h"
@@ -534,6 +535,10 @@ PyMOD_INIT_FUNC(Part)
     Part::GeomSurfaceOfRevolution 	::init();
     Part::GeomSurfaceOfExtrusion  	::init();
     Part::Datum                   	::init();
+    Part::DatumPlane             	::init();
+    Part::DatumLine                	::init();
+    Part::DatumPoint               	::init();
+    Part::LocalCoordinateSystem     ::init();
 
     // Geometry2d types
     Part::Geometry2d              ::init();

src/Mod/Part/App/AttachExtension.cpp

@@ -411,33 +411,18 @@ void AttachExtension::extensionOnChanged(const App::Property* prop)
             bool bAttached = false;
             try{
                 bAttached = positionBySupport();
-            } catch (Base::Exception &e) {
+            }
+            catch (Base::Exception &e) {
                 getExtendedObject()->setStatus(App::Error, true);
                 Base::Console().Error("PositionBySupport: %s\n",e.what());
                 //set error message - how?
-            } catch (Standard_Failure &e){
+            }
+            catch (Standard_Failure &e){
                 getExtendedObject()->setStatus(App::Error, true);
                 Base::Console().Error("PositionBySupport: %s\n",e.GetMessageString());
             }
-            // Hide properties when not applicable to reduce user confusion
-
-            eMapMode mmode = eMapMode(this->MapMode.getValue());
-
-            bool modeIsPointOnCurve = mmode == mmNormalToPath ||
-                mmode == mmFrenetNB || mmode == mmFrenetTN || mmode == mmFrenetTB ||
-                mmode == mmRevolutionSection || mmode == mmConcentric;
-
-            // MapPathParameter is only used if there is a reference to one edge and not edge + vertex
-            bool hasOneRef = false;
-            if (_props.attacher && _props.attacher->subnames.size() == 1) {
-                hasOneRef = true;
-            }
-
-            this->MapPathParameter.setStatus(App::Property::Status::Hidden, !bAttached || !(modeIsPointOnCurve && hasOneRef));
-            this->MapReversed.setStatus(App::Property::Status::Hidden, !bAttached);
-            this->AttachmentOffset.setStatus(App::Property::Status::Hidden, !bAttached);
-            getPlacement().setReadOnly(bAttached && mmode != mmTranslate); //for mmTranslate, orientation should remain editable even when attached.
 
+            updateSinglePropertyStatus(bAttached);
         }
         if (prop == &AttacherEngine) {
             AttacherType.setValue(enumToClass(AttacherEngine.getValueAsString()));
@@ -508,27 +493,9 @@ void AttachExtension::onExtendedDocumentRestored()
 
         restoreAttacherEngine(this);
 
-        // Hide properties when not applicable to reduce user confusion
         bool bAttached = positionBySupport();
-        eMapMode mmode = eMapMode(this->MapMode.getValue());
-        bool modeIsPointOnCurve =
-                (mmode == mmNormalToPath ||
-                 mmode == mmFrenetNB ||
-                 mmode == mmFrenetTN ||
-                 mmode == mmFrenetTB ||
-                 mmode == mmRevolutionSection ||
-                 mmode == mmConcentric);
 
-        // MapPathParameter is only used if there is a reference to one edge and not edge + vertex
-        bool hasOneRef = false;
-        if (_props.attacher && _props.attacher->subnames.size() == 1) {
-            hasOneRef = true;
-        }
-
-        this->MapPathParameter.setStatus(App::Property::Status::Hidden, !bAttached || !(modeIsPointOnCurve && hasOneRef));
-        this->MapReversed.setStatus(App::Property::Status::Hidden, !bAttached);
-        this->AttachmentOffset.setStatus(App::Property::Status::Hidden, !bAttached);
-        getPlacement().setReadOnly(bAttached && mmode != mmTranslate); //for mmTranslate, orientation should remain editable even when attached.
+        updateSinglePropertyStatus(bAttached);
     }
     catch (Base::Exception&) {
     }
@@ -536,7 +503,7 @@ void AttachExtension::onExtendedDocumentRestored()
     }
 }
 
-void AttachExtension::updatePropertyStatus(bool bAttached, bool base)
+void AttachExtension::updateSinglePropertyStatus(bool bAttached, bool base)
 {
     auto& props = base ? this->_baseProps : this->_props;
     if (!props.mapMode) {
@@ -550,12 +517,9 @@ void AttachExtension::updatePropertyStatus(bool bAttached, bool base)
          || mmode == mmFrenetTB || mmode == mmRevolutionSection || mmode == mmConcentric);
 
     // MapPathParameter is only used if there is a reference to one edge and not edge + vertex
-    bool hasOneRef = false;
-    if (props.attacher && props.attacher->subnames.size() == 1) {
-        hasOneRef = true;
-    }
-    props.mapPathParameter->setStatus(App::Property::Status::Hidden,
-                                      !bAttached || !(modeIsPointOnCurve && hasOneRef));
+    bool hasOneRef = props.attacher && props.attacher->subnames.size() == 1;
+
+    props.mapPathParameter->setStatus(App::Property::Status::Hidden, !bAttached || !(modeIsPointOnCurve && hasOneRef));
     props.mapReversed->setStatus(App::Property::Status::Hidden, !bAttached);
 
     if (base) {
@@ -564,11 +528,18 @@ void AttachExtension::updatePropertyStatus(bool bAttached, bool base)
     else {
         this->AttachmentOffset.setStatus(App::Property::Status::Hidden, !bAttached);
         if (getExtendedContainer()) {
-            getPlacement().setReadOnly(
-                bAttached && mmode != mmTranslate);  // for mmTranslate, orientation should remain
-                                                     // editable even when attached.
+            // for mmTranslate, orientation should remain editable even when attached.
+            getPlacement().setReadOnly(bAttached && mmode != mmTranslate);
         }
-        updatePropertyStatus(bAttached, true);
+    }
+}
+
+void AttachExtension::updatePropertyStatus(bool bAttached, bool base)
+{
+    updateSinglePropertyStatus(bAttached, base);
+
+    if (!base) {
+        updateSinglePropertyStatus(bAttached, true);
     }
 }
 

src/Mod/Part/App/AttachExtension.h

@@ -35,7 +35,6 @@
 #include <Base/Placement.h>
 
 #include "Attacher.h"
-#include "PartFeature.h"
 
 
 namespace Part
@@ -146,7 +145,10 @@ protected:
 
 public:
     void updateAttacherVals(bool base = false) const;
+    // This update both _props and _baseProps if base = false
     void updatePropertyStatus(bool attached, bool base = false);
+    // This update only _props if base = false
+    void updateSinglePropertyStatus(bool attached, bool base = false);
 
 private:
     struct _Properties: Properties

src/Mod/Part/App/Attacher.cpp

@@ -27,6 +27,7 @@
 # include <BRepAdaptor_Surface.hxx>
 # include <BRepBuilderAPI_MakeEdge.hxx>
 # include <BRepBuilderAPI_MakeFace.hxx>
+# include <BRepBuilderAPI_MakeVertex.hxx>
 # include <BRepExtrema_DistShapeShape.hxx>
 # include <BRepGProp.hxx>
 # include <BRepIntCurveSurface_Inter.hxx>
@@ -300,7 +301,8 @@ Base::Placement AttachEngine::placementFactory(const gp_Dir &ZAxis,
     gp_Ax3 ax3;//OCC representation of the final placement
     if (!makeYVertical) {
         ax3 = gp_Ax3(Origin, ZAxis, XAxis);
-    } else if (!makeLegacyFlatFaceOrientation) {
+    }
+    else if (!makeLegacyFlatFaceOrientation) {
         //align Y along Z, if possible
         gp_Vec YAxis(0.0,0.0,1.0);
         XAxis = YAxis.Crossed(gp_Vec(ZAxis));
@@ -309,7 +311,8 @@ Base::Placement AttachEngine::placementFactory(const gp_Dir &ZAxis,
             XAxis = (gp_Vec(1,0,0)*ZAxis.Z()).Normalized();
         }
         ax3 = gp_Ax3(Origin, ZAxis, XAxis);
-    } else if (makeLegacyFlatFaceOrientation) {
+    }
+    else if (makeLegacyFlatFaceOrientation) {
         //find out, to which axis of support Normal is closest to.
         //The result will be written into pos variable (0..2 = X..Z)
         if (!placeOfRef)
@@ -385,13 +388,11 @@ void AttachEngine::suggestMapModes(SuggestResult &result) const
     result.message = SuggestResult::srLinkBroken;
     result.bestFitMode = mmDeactivated;
 
-
-    std::vector<App::GeoFeature*> parts;
     std::vector<const TopoDS_Shape*> shapes;
     std::vector<TopoDS_Shape> shapeStorage;
     std::vector<eRefType> typeStr;
     try{
-        readLinks(getRefObjects(),subnames, parts, shapes, shapeStorage, typeStr);
+        readLinks(getRefObjects(),subnames, shapes, shapeStorage, typeStr);
     } catch (Base::Exception &err) {
         result.references_Types = typeStr;
         result.message = SuggestResult::srLinkBroken;
@@ -577,11 +578,10 @@ eRefType AttachEngine::getShapeType(const App::DocumentObject *obj, const std::s
     //const_cast is worth here, to keep obj argument const. We are not going to write anything to obj through this temporary link.
     tmpLink.setValue(const_cast<App::DocumentObject*>(obj), subshape.c_str());
 
-    std::vector<App::GeoFeature*> parts;
     std::vector<const TopoDS_Shape*> shapes;
     std::vector<TopoDS_Shape> copiedShapeStorage;
     std::vector<eRefType> types;
-    readLinks(tmpLink.getValues(),tmpLink.getSubValues(), parts, shapes, copiedShapeStorage, types);
+    readLinks(tmpLink.getValues(), tmpLink.getSubValues(), shapes, copiedShapeStorage, types);
 
     assert(types.size() == 1);
     return types[0];
@@ -814,105 +814,79 @@ GProp_GProps AttachEngine::getInertialPropsOfShape(const std::vector<const TopoD
 
 /*!
  * \brief AttachEngine3D::readLinks
- * \param parts
  * \param shapes
  * \param storage is a buffer storing what some of the pointers in shapes point to. It is needed, since
  * subshapes are copied in the process (but copying a whole shape of an object can potentially be slow).
  */
-void AttachEngine::readLinks(const std::vector<App::DocumentObject*> &objs,
-                             const std::vector<std::string> &sub,
-                             std::vector<App::GeoFeature*> &geofs,
+void AttachEngine::readLinks(const std::vector<App::DocumentObject*>& objs,
+                             const std::vector<std::string> &subs,
                              std::vector<const TopoDS_Shape*> &shapes,
                              std::vector<TopoDS_Shape> &storage,
                              std::vector<eRefType> &types)
 {
-    geofs.resize(objs.size());
     storage.reserve(objs.size());
     shapes.resize(objs.size());
     types.resize(objs.size());
     for (std::size_t i = 0; i < objs.size(); i++) {
-        if (!objs[i]->getTypeId().isDerivedFrom(App::GeoFeature::getClassTypeId())) {
-            FC_THROWM(AttachEngineException,
-                      "AttachEngine3D: attached to a non App::GeoFeature '"
-                          << objs[i]->getNameInDocument() << "'");
-        }
         auto* geof = dynamic_cast<App::GeoFeature*>(objs[i]);
-        geofs[i] = geof;
-        Part::TopoShape shape;
-        if (geof->isDerivedFrom(App::Plane::getClassTypeId())) {
-            // obtain Z axis and origin of placement
-            Base::Vector3d norm;
-            geof->Placement.getValue().getRotation().multVec(Base::Vector3d(0.0, 0.0, 1.0), norm);
-            Base::Vector3d org;
-            geof->Placement.getValue().multVec(Base::Vector3d(), org);
-            // make shape - an local-XY plane infinite face
-            gp_Pln plane = gp_Pln(gp_Pnt(org.x, org.y, org.z), gp_Dir(norm.x, norm.y, norm.z));
-            TopoDS_Shape myShape = BRepBuilderAPI_MakeFace(plane).Shape();
-            myShape.Infinite(true);
-            storage.emplace_back(myShape);
-            shapes[i] = &(storage[storage.size() - 1]);
+        if (!geof) {
+            // Accept App::Links to GeoFeatures
+            geof = dynamic_cast<App::GeoFeature*>(objs[i]->getLinkedObject());
+            if (!geof) {
+                FC_THROWM(AttachEngineException,
+                    "AttachEngine3D: attached to a non App::GeoFeature '" << objs[i]->getNameInDocument() << "'");
+            }
         }
-        else if (geof->isDerivedFrom(App::Line::getClassTypeId())) {
-            // obtain X axis and origin of placement
-            // note an inconsistency: App::Line is along local X, PartDesign::DatumLine is along
-            // local Z.
-            Base::Vector3d dir;
-            geof->Placement.getValue().getRotation().multVec(Base::Vector3d(1.0, 0.0, 0.0), dir);
-            Base::Vector3d org;
-            geof->Placement.getValue().multVec(Base::Vector3d(), org);
-            // make shape - an infinite line along local X axis
-            gp_Lin line = gp_Lin(gp_Pnt(org.x, org.y, org.z), gp_Dir(dir.x, dir.y, dir.z));
-            TopoDS_Shape myShape = BRepBuilderAPI_MakeEdge(line).Shape();
-            myShape.Infinite(true);
-            storage.emplace_back(myShape);
-            shapes[i] = &(storage[storage.size() - 1]);
-        }
-        else {
-            try {
-                shape = Part::Feature::getTopoShape(geof, sub[i].c_str(), true);
-                for (;;) {
-                    if (shape.isNull()) {
-                        FC_THROWM(AttachEngineException,
-                                  "AttachEngine3D: subshape not found "
-                                      << objs[i]->getNameInDocument() << '.' << sub[i]);
-                    }
-                    if (shape.shapeType() != TopAbs_COMPOUND
-                        || shape.countSubShapes(TopAbs_SHAPE) != 1) {
-                        break;
-                    }
-                    // auto extract the single sub-shape from a compound
-                    shape = shape.getSubTopoShape(TopAbs_SHAPE, 1);
+        TopoDS_Shape myShape;
+
+        try {
+            // getTopoShape support fully qualified subnames and should return shape with correct
+            // global placement.
+            Part::TopoShape shape = Part::Feature::getTopoShape(objs[i], subs[i].c_str(), true);
+            for (;;) {
+                if (shape.isNull()) {
+                    FC_THROWM(AttachEngineException,
+                                "AttachEngine3D: subshape not found "
+                                    << objs[i]->getNameInDocument() << '.' << subs[i]);
                 }
-                storage.emplace_back(shape.getShape());
+                if (shape.shapeType() != TopAbs_COMPOUND
+                    || shape.countSubShapes(TopAbs_SHAPE) != 1) {
+                    break;
+                }
+                // auto extract the single sub-shape from a compound
+                shape = shape.getSubTopoShape(TopAbs_SHAPE, 1);
             }
-            catch (Standard_Failure& e) {
-                FC_THROWM(AttachEngineException,
-                          "AttachEngine3D: subshape not found " << objs[i]->getNameInDocument()
-                                                                << '.' << sub[i] << std::endl
-                                                                << e.GetMessageString());
-            }
-            catch (Base::CADKernelError& e) {
-                FC_THROWM(AttachEngineException,
-                          "AttachEngine3D: subshape not found " << objs[i]->getNameInDocument()
-                                                                << '.' << sub[i] << std::endl
-                                                                << e.what());
-            }
-            if (storage.back().IsNull()) {
-                FC_THROWM(AttachEngineException,
-                          "AttachEngine3D: null subshape " << objs[i]->getNameInDocument() << '.'
-                                                           << sub[i]);
-            }
-            shapes[i] = &(storage.back());
+
+            myShape = shape.getShape();
         }
+        catch (Standard_Failure& e) {
+            FC_THROWM(AttachEngineException,
+                        "AttachEngine3D: subshape not found " << objs[i]->getNameInDocument()
+                                                            << '.' << subs[i] << std::endl
+                                                            << e.GetMessageString());
+        }
+        catch (Base::CADKernelError& e) {
+            FC_THROWM(AttachEngineException,
+                        "AttachEngine3D: subshape not found " << objs[i]->getNameInDocument()
+                                                            << '.' << subs[i] << std::endl
+                                                            << e.what());
+        }
+        if (myShape.IsNull()) {
+            FC_THROWM(AttachEngineException,
+                        "AttachEngine3D: null subshape " << objs[i]->getNameInDocument() << '.'
+                                                        << subs[i]);
+        }
+
+        storage.emplace_back(myShape);
+        shapes[i] = &(storage.back());
 
         // FIXME: unpack single-child compounds here? Compounds are not used so far, so it should be
         // considered later, when the need arises.
         types[i] = getShapeType(*(shapes[i]));
-        if (sub[i].length() == 0) {
+        if (subs[i].length() == 0) {
             types[i] = eRefType(types[i] | rtFlagHasPlacement);
         }
     }
-
 }
 
 void AttachEngine::throwWrongMode(eMapMode mmode)
@@ -977,6 +951,7 @@ Base::Placement AttachEngine::calculateAttachedPlacement(const Base::Placement&
     for (auto obj : objs) {
         ++i;
         auto& sub = subnames[i];
+        obj = obj->getSubObject(sub.c_str());
         auto& shadow = shadowSubs[i];
         if (shadow.empty() || !Data::hasMissingElement(sub.c_str())) {
             continue;
@@ -1165,20 +1140,20 @@ AttachEngine3D::_calculateAttachedPlacement(const std::vector<App::DocumentObjec
         throw ExceptionCancel();  // to be handled in positionBySupport, to not do anything if
                                   // disabled
     }
-    std::vector<App::GeoFeature*> parts;
     std::vector<const TopoDS_Shape*> shapes;
     std::vector<TopoDS_Shape> copiedShapeStorage;
     std::vector<eRefType> types;
-    readLinks(objs, subs, parts, shapes, copiedShapeStorage, types);
+    readLinks(objs, subs, shapes, copiedShapeStorage, types);
 
-    if (parts.empty()) {
+    if (shapes.empty()) {
         throw ExceptionCancel();
     }
 
     // common stuff for all map modes
-    gp_Pnt refOrg(0.0, 0.0, 0.0);  // origin of linked object
-    Base::Placement Place = parts[0]->Placement.getValue();
-    refOrg = gp_Pnt(Place.getPosition().x, Place.getPosition().y, Place.getPosition().z);
+    App::DocumentObject* subObj = objs[0]->getSubObject(subs[0].c_str());
+    Base::Placement Place = App::GeoFeature::getGlobalPlacement(subObj, objs[0], subs[0]);
+    Base::Vector3d vec = Place.getPosition();
+    gp_Pnt refOrg = gp_Pnt(vec.x, vec.y, vec.z);  // origin of linked object
 
     // variables to derive the actual placement.
     // They are to be set, depending on the mode:
@@ -2108,21 +2083,21 @@ AttachEngineLine::_calculateAttachedPlacement(const std::vector<App::DocumentObj
 
     Base::Placement plm;
     if (!bReUsed) {
-        std::vector<App::GeoFeature*> parts;
         std::vector<const TopoDS_Shape*> shapes;
         std::vector<TopoDS_Shape> copiedShapeStorage;
         std::vector<eRefType> types;
-        readLinks(objs, subs, parts, shapes, copiedShapeStorage, types);
+        readLinks(objs, subs, shapes, copiedShapeStorage, types);
 
-        if (parts.empty()) {
+        if (shapes.empty()) {
             throw ExceptionCancel();
         }
 
 
         // common stuff for all map modes
-        gp_Pnt refOrg(0.0, 0.0, 0.0);
-        Base::Placement Place = parts[0]->Placement.getValue();
-        refOrg = gp_Pnt(Place.getPosition().x, Place.getPosition().y, Place.getPosition().z);
+        App::DocumentObject* subObj = objs[0]->getSubObject(subs[0].c_str());
+        Base::Placement Place = App::GeoFeature::getGlobalPlacement(subObj, objs[0], subs[0]);
+        Base::Vector3d vec = Place.getPosition();
+        gp_Pnt refOrg = gp_Pnt(vec.x, vec.y, vec.z);  // origin of linked object
 
         // variables to derive the actual placement.
         // They are to be set, depending on the mode:
@@ -2475,13 +2450,12 @@ AttachEnginePoint::_calculateAttachedPlacement(const std::vector<App::DocumentOb
 
     Base::Placement plm;
     if (!bReUsed) {
-        std::vector<App::GeoFeature*> parts;
         std::vector<const TopoDS_Shape*> shapes;
         std::vector<TopoDS_Shape> copiedShapeStorage;
         std::vector<eRefType> types;
-        readLinks(objs, subs, parts, shapes, copiedShapeStorage, types);
+        readLinks(objs, subs, shapes, copiedShapeStorage, types);
 
-        if (parts.empty()) {
+        if (shapes.empty()) {
             throw ExceptionCancel();
         }
 

src/Mod/Part/App/Attacher.h

@@ -429,7 +429,7 @@ protected:
         return ret;
     }
     static void readLinks(const std::vector<App::DocumentObject*> &objs,
-                          const std::vector<std::string> &subs, std::vector<App::GeoFeature *> &geofs,
+                          const std::vector<std::string> &subs,
                           std::vector<const TopoDS_Shape*>& shapes, std::vector<TopoDS_Shape> &storage,
                           std::vector<eRefType> &types);
 

src/Mod/Part/App/CMakeLists.txt

@@ -213,6 +213,8 @@ SET(Features_SRCS
     CustomFeature.h
     BodyBase.h
     BodyBase.cpp
+    Datums.cpp
+    Datums.h
     DatumFeature.cpp
     DatumFeature.h
     AttachExtension.h

src/Mod/Part/App/Datums.cpp

@@ -0,0 +1,63 @@
+/***************************************************************************
+ *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "PreCompiled.h"
+
+#include "Datums.h"
+
+
+using namespace Part;
+using namespace Attacher;
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(Part::DatumPlane, App::Plane)
+
+Part::DatumPlane::DatumPlane()
+{
+    AttachExtension::initExtension(this);
+    this->setAttacher(new AttachEnginePlane);
+}
+
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(Part::DatumLine, App::Line)
+
+Part::DatumLine::DatumLine()
+{
+    AttachExtension::initExtension(this);
+    this->setAttacher(new AttachEngineLine);
+}
+
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(Part::DatumPoint, App::Point)
+
+Part::DatumPoint::DatumPoint()
+{
+    AttachExtension::initExtension(this);
+    this->setAttacher(new AttachEnginePoint);
+}
+
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(Part::LocalCoordinateSystem, App::LocalCoordinateSystem)
+
+Part::LocalCoordinateSystem::LocalCoordinateSystem()
+{
+    AttachExtension::initExtension(this);
+}

src/Mod/Part/App/Datums.h

@@ -0,0 +1,84 @@
+/***************************************************************************
+ *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef PART_DATUMS_H
+#define PART_DATUMS_H
+
+#include <App/Datums.h>
+
+#include "AttachExtension.h"
+
+namespace Part
+{
+
+class PartExport DatumPlane : public App::Plane, public AttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(Part::DatumPlane);
+
+public:
+    DatumPlane();
+    ~DatumPlane() override = default;
+    const char* getViewProviderName() const override {
+        return "PartGui::ViewProviderPlane";
+    }
+};
+
+class PartExport DatumLine : public App::Line, public AttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(Part::DatumLine);
+
+public:
+    DatumLine();
+    ~DatumLine() override = default;
+    const char* getViewProviderName() const override {
+        return "PartGui::ViewProviderLine";
+    }
+};
+
+class PartExport DatumPoint : public App::Point, public AttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(Part::DatumPoint);
+
+public:
+    DatumPoint();
+    ~DatumPoint() override = default;
+    const char* getViewProviderName() const override {
+        return "PartGui::ViewProviderPoint";
+    }
+};
+
+class PartExport LocalCoordinateSystem : public App::LocalCoordinateSystem, public AttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(Part::LocalCoordinateSystem);
+
+public:
+    LocalCoordinateSystem();
+    ~LocalCoordinateSystem() override = default;
+    const char* getViewProviderName() const override {
+        return "PartGui::ViewProviderLCS";
+    }
+};
+
+} //namespace Part
+
+
+#endif // PART_DATUMS_H

src/Mod/Part/App/PartFeature.cpp

@@ -1018,7 +1018,7 @@ static TopoShape _getTopoShape(const App::DocumentObject* obj,
             if (linked->isDerivedFrom(App::Line::getClassTypeId())) {
                 static TopoDS_Shape _shape;
                 if (_shape.IsNull()) {
-                    BRepBuilderAPI_MakeEdge builder(gp_Lin(gp_Pnt(0, 0, 0), gp_Dir(1, 0, 0)));
+                    BRepBuilderAPI_MakeEdge builder(gp_Lin(gp_Pnt(0, 0, 0), gp_Dir(0, 0, 1)));
                     _shape = builder.Shape();
                     _shape.Infinite(Standard_True);
                 }
@@ -1076,6 +1076,7 @@ static TopoShape _getTopoShape(const App::DocumentObject* obj,
                     shape = TopoShape(tag, hasher, _shape);
                 }
             }
+
             if (!shape.isNull()) {
                 shape.transformShape(mat * linkMat, false, true);
                 return shape;

src/Mod/Part/Gui/AppPartGui.cpp

@@ -47,6 +47,7 @@
 #include "ViewProvider.h"
 #include "ViewProvider2DObject.h"
 #include "ViewProviderAttachExtension.h"
+#include "ViewProviderDatum.h"
 #include "ViewProviderGridExtension.h"
 #include "ViewProviderBoolean.h"
 #include "ViewProviderBox.h"
@@ -167,6 +168,10 @@ PyMOD_INIT_FUNC(PartGui)
     PartGui::ViewProviderGridExtensionPython        ::init();
     PartGui::ViewProviderSplineExtension            ::init();
     PartGui::ViewProviderSplineExtensionPython      ::init();
+    PartGui::ViewProviderLine                       ::init();
+    PartGui::ViewProviderPlane                      ::init();
+    PartGui::ViewProviderPoint                      ::init();
+    PartGui::ViewProviderLCS                        ::init();
     PartGui::ViewProviderPartExt                    ::init();
     PartGui::ViewProviderPart                       ::init();
     PartGui::ViewProviderPrimitive                  ::init();

src/Mod/Part/Gui/CMakeLists.txt

@@ -164,6 +164,8 @@ SET(PartGui_SRCS
     ViewProvider.h
     ViewProviderAttachExtension.h
     ViewProviderAttachExtension.cpp
+    ViewProviderDatum.cpp
+    ViewProviderDatum.h
     ViewProviderExt.cpp
     ViewProviderExt.h
     ViewProviderReference.cpp

src/Mod/Part/Gui/Command.cpp

@@ -32,6 +32,7 @@
 #endif
 
 #include <App/Document.h>
+#include <App/GeoFeature.h>
 #include <App/DocumentObjectGroup.h>
 #include <Base/Console.h>
 #include <Base/Exception.h>
@@ -51,6 +52,8 @@
 #include <Gui/View3DInventorViewer.h>
 #include <Gui/WaitCursor.h>
 
+#include <Mod/Part/App/Datums.h>
+
 #include "BoxSelection.h"
 #include "CrossSections.h"
 #include "DlgBooleanOperation.h"
@@ -2211,6 +2214,193 @@ bool CmdPartSectionCut::isActive()
     return hasActiveDocument();
 }
 
+
+//===========================================================================
+// Part_CoordinateSystem
+//===========================================================================
+
+namespace {
+    QString getAutoGroupCommandStr()
+        // Helper function to get the python code to add the newly created object to the active Part/Body object if present
+    {
+        App::GeoFeature* activeObj = Gui::Application::Instance->activeView()->getActiveObject<App::GeoFeature*>(PDBODYKEY);
+        if (!activeObj) {
+            activeObj = Gui::Application::Instance->activeView()->getActiveObject<App::GeoFeature*>(PARTKEY);
+        }
+
+        if (activeObj) {
+            QString activeName = QString::fromLatin1(activeObj->getNameInDocument());
+            return QString::fromLatin1("App.ActiveDocument.getObject('%1\').addObject(obj)\n").arg(activeName);
+        }
+
+        return QString::fromLatin1("# Object created at document root.");
+    }
+}
+
+DEF_STD_CMD_A(CmdPartCoordinateSystem)
+
+CmdPartCoordinateSystem::CmdPartCoordinateSystem()
+    : Command("Part_CoordinateSystem")
+{
+    sGroup = QT_TR_NOOP("Part");
+    sMenuText = QT_TR_NOOP("Create a coordinate system");
+    sToolTipText = QT_TR_NOOP("A coordinate system object that can be attached to other objects.");
+    sWhatsThis = "Part_CoordinateSystem";
+    sStatusTip = sToolTipText;
+    sPixmap = "Std_CoordinateSystem";
+}
+
+void CmdPartCoordinateSystem::activated(int iMsg)
+{
+    Q_UNUSED(iMsg);
+
+    openCommand(QT_TRANSLATE_NOOP("Command", "Add a coordinate system"));
+
+    std::string name = getUniqueObjectName("LCS");
+    doCommand(Doc, "obj = App.activeDocument().addObject('Part::LocalCoordinateSystem','%s')", name.c_str());
+    doCommand(Doc, getAutoGroupCommandStr().toUtf8());
+    doCommand(Doc, "obj.Visibility = True");
+    doCommand(Doc, "obj.ViewObject.doubleClicked()");
+}
+
+bool CmdPartCoordinateSystem::isActive()
+{
+    return hasActiveDocument();
+}
+
+//===========================================================================
+// Part_Plane
+//===========================================================================
+DEF_STD_CMD_A(CmdPartPlane)
+
+CmdPartPlane::CmdPartPlane()
+    : Command("Part_Plane")
+{
+    sGroup = QT_TR_NOOP("Part");
+    sMenuText = QT_TR_NOOP("Create a datum plane");
+    sToolTipText = QT_TR_NOOP("A plane object that can be attached to other objects.");
+    sWhatsThis = "Part_Plane";
+    sStatusTip = sToolTipText;
+    sPixmap = "Std_Plane";
+}
+
+void CmdPartPlane::activated(int iMsg)
+{
+    Q_UNUSED(iMsg);
+
+    openCommand(QT_TRANSLATE_NOOP("Command", "Add a datum plane"));
+
+    std::string name = getUniqueObjectName("Plane");
+    doCommand(Doc, "obj = App.activeDocument().addObject('Part::DatumPlane','%s')", name.c_str());
+    doCommand(Doc, getAutoGroupCommandStr().toUtf8());
+    doCommand(Doc, "obj.ViewObject.doubleClicked()");
+}
+
+bool CmdPartPlane::isActive()
+{
+    return hasActiveDocument();
+}
+
+//===========================================================================
+// Part_Line
+//===========================================================================
+DEF_STD_CMD_A(CmdPartLine)
+
+CmdPartLine::CmdPartLine()
+    : Command("Part_Line")
+{
+    sGroup = QT_TR_NOOP("Part");
+    sMenuText = QT_TR_NOOP("Create a datum line");
+    sToolTipText = QT_TR_NOOP("A line object that can be attached to other objects.");
+    sWhatsThis = "Part_Line";
+    sStatusTip = sToolTipText;
+    sPixmap = "Std_Axis";
+}
+
+void CmdPartLine::activated(int iMsg)
+{
+    Q_UNUSED(iMsg);
+
+    openCommand(QT_TRANSLATE_NOOP("Command", "Add a datum line"));
+
+    std::string name = getUniqueObjectName("Line");
+    doCommand(Doc, "obj = App.activeDocument().addObject('Part::DatumLine','%s')", name.c_str());
+    doCommand(Doc, getAutoGroupCommandStr().toUtf8());
+    doCommand(Doc, "obj.ViewObject.doubleClicked()");
+}
+
+bool CmdPartLine::isActive()
+{
+    return hasActiveDocument();
+}
+
+//===========================================================================
+// Part_Point
+//===========================================================================
+DEF_STD_CMD_A(CmdPartPoint)
+
+CmdPartPoint::CmdPartPoint()
+    : Command("Part_Point")
+{
+    sGroup = QT_TR_NOOP("Part");
+    sMenuText = QT_TR_NOOP("Create a datum point");
+    sToolTipText = QT_TR_NOOP("A point object that can be attached to other objects.");
+    sWhatsThis = "Part_Point";
+    sStatusTip = sToolTipText;
+    sPixmap = "Std_Point";
+}
+
+void CmdPartPoint::activated(int iMsg)
+{
+    Q_UNUSED(iMsg);
+
+    openCommand(QT_TRANSLATE_NOOP("Command", "Add a datum point"));
+
+    std::string name = getUniqueObjectName("Point");
+    doCommand(Doc, "obj = App.activeDocument().addObject('Part::DatumPoint','%s')", name.c_str());
+    doCommand(Doc, getAutoGroupCommandStr().toUtf8());
+    doCommand(Doc, "obj.ViewObject.doubleClicked()");
+}
+
+bool CmdPartPoint::isActive()
+{
+    return hasActiveDocument();
+}
+
+
+//===========================================================================
+// Part_Datums
+//===========================================================================
+class CmdPartDatums : public Gui::GroupCommand
+{
+public:
+    CmdPartDatums()
+        : GroupCommand("Part_Datums")
+    {
+        sGroup = QT_TR_NOOP("Part");
+        sMenuText = QT_TR_NOOP("Create a datum");
+        sToolTipText = QT_TR_NOOP("Create a datum object (LCS, Plane, Line, Point) that can be attached to other objects.");
+        sWhatsThis = "Part_Datums";
+        sStatusTip = sToolTipText;
+
+        setCheckable(false);
+
+        addCommand("Part_CoordinateSystem");
+        addCommand("Part_Plane");
+        addCommand("Part_Line");
+        addCommand("Part_Point");
+    }
+
+    const char* className() const override
+    {
+        return "CmdPartDatums";
+    }
+
+    bool isActive() override
+    {
+        return hasActiveDocument();
+    }
+};
 //---------------------------------------------------------------
 
 void CreatePartCommands()
@@ -2256,4 +2446,10 @@ void CreatePartCommands()
     rcCmdMgr.addCommand(new CmdBoxSelection());
     rcCmdMgr.addCommand(new CmdPartProjectionOnSurface());
     rcCmdMgr.addCommand(new CmdPartSectionCut());
+
+    rcCmdMgr.addCommand(new CmdPartCoordinateSystem());
+    rcCmdMgr.addCommand(new CmdPartPlane());
+    rcCmdMgr.addCommand(new CmdPartLine());
+    rcCmdMgr.addCommand(new CmdPartPoint());
+    rcCmdMgr.addCommand(new CmdPartDatums());
 }

src/Mod/Part/Gui/TaskAttacher.cpp

@@ -33,6 +33,7 @@
 
 #include <App/Application.h>
 #include <App/Document.h>
+#include <App/ElementNamingUtils.h>
 #include <App/ObjectIdentifier.h>
 #include <App/Datums.h>
 #include <App/Part.h>
@@ -43,6 +44,7 @@
 #include <Gui/DocumentObserver.h>
 #include <Gui/Selection.h>
 #include <Gui/ViewProvider.h>
+#include <Base/Tools.h>
 #include <Mod/Part/App/AttachExtension.h>
 #include <Mod/Part/App/DatumFeature.h>
 #include <Mod/Part/Gui/AttacherTexts.h>
@@ -62,29 +64,22 @@ namespace sp = std::placeholders;
 // Create reference name from PropertyLinkSub values in a translatable fashion
 const QString makeRefString(const App::DocumentObject* obj, const std::string& sub)
 {
-    if (!obj)
+    if (!obj) {
         return QObject::tr("No reference selected");
-
-    if (obj->isDerivedFrom<App::DatumElement>() ||
-        obj->isDerivedFrom<Part::Datum>())
-        // App::Plane, Line or Datum feature
-        return QString::fromLatin1(obj->getNameInDocument());
-
-    if ((sub.size() > 4) && (sub.substr(0,4) == "Face")) {
-        int subId = std::atoi(&sub[4]);
-        return QString::fromLatin1(obj->getNameInDocument()) + QString::fromLatin1(":") + QObject::tr("Face") + QString::number(subId);
-    } else if ((sub.size() > 4) && (sub.substr(0,4) == "Edge")) {
-        int subId = std::atoi(&sub[4]);
-        return QString::fromLatin1(obj->getNameInDocument()) + QString::fromLatin1(":") + QObject::tr("Edge") + QString::number(subId);
-    } else if ((sub.size() > 6) && (sub.substr(0,6) == "Vertex")) {
-        int subId = std::atoi(&sub[6]);
-        return QString::fromLatin1(obj->getNameInDocument()) + QString::fromLatin1(":") + QObject::tr("Vertex") + QString::number(subId);
-    } else {
-        //something else that face/edge/vertex. Can be empty string.
-        return QString::fromLatin1(obj->getNameInDocument())
-                + (sub.length()>0 ? QString::fromLatin1(":") : QString())
-                + QString::fromLatin1(sub.c_str());
     }
+
+    if (obj->isDerivedFrom<App::DatumElement>() || obj->isDerivedFrom<Part::Datum>()) {
+        return QString::fromLatin1(obj->getNameInDocument());
+    }
+
+    // Hide the TNP string from the user. ie show "Body.Pad.Face6"  and not : 
+    // "Body.Pad.;#a:1;:G0;XTR;:Hc94:8,F.Face6"
+    App::ElementNamePair el;
+    App::GeoFeature::resolveElement(obj, sub.c_str(), el, true);
+
+    return QString::fromLatin1(obj->getNameInDocument())
+        + (sub.length() > 0 ? QString::fromLatin1(":") : QString())
+        + QString::fromLatin1(el.oldName.c_str());
 }
 
 void TaskAttacher::makeRefStrings(std::vector<QString>& refstrings, std::vector<std::string>& refnames) {
@@ -98,17 +93,18 @@ void TaskAttacher::makeRefStrings(std::vector<QString>& refstrings, std::vector<
             // for Origin or Datum features refnames is empty but we need a non-empty return value
             if (refnames[r].empty())
                 refnames[r] = refs[r]->getNameInDocument();
-        } else {
+        }
+        else {
             refstrings.push_back(QObject::tr("No reference selected"));
             refnames.emplace_back("");
         }
     }
 }
 
-TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject *ViewProvider, QWidget *parent,
-                           QString picture, QString text, TaskAttacher::VisibilityFunction visFunc)
+TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject* ViewProvider, QWidget* parent,
+    QString picture, QString text, TaskAttacher::VisibilityFunction visFunc)
     : TaskBox(Gui::BitmapFactory().pixmap(picture.toLatin1()), text, true, parent)
-    , SelectionObserver(ViewProvider)
+    , SelectionObserver(ViewProvider, true, Gui::ResolveMode::NoResolve)
     , ViewProvider(ViewProvider)
     , ui(new Ui_TaskAttacher)
     , visibilityFunc(visFunc)
@@ -125,37 +121,37 @@ TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject *ViewProvider, QWidge
 
     // clang-format off
     connect(ui->attachmentOffsetX, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetXChanged);
+        this, &TaskAttacher::onAttachmentOffsetXChanged);
     connect(ui->attachmentOffsetY, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetYChanged);
+        this, &TaskAttacher::onAttachmentOffsetYChanged);
     connect(ui->attachmentOffsetZ, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetZChanged);
+        this, &TaskAttacher::onAttachmentOffsetZChanged);
     connect(ui->attachmentOffsetYaw, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetYawChanged);
+        this, &TaskAttacher::onAttachmentOffsetYawChanged);
     connect(ui->attachmentOffsetPitch, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetPitchChanged);
+        this, &TaskAttacher::onAttachmentOffsetPitchChanged);
     connect(ui->attachmentOffsetRoll, qOverload<double>(&Gui::QuantitySpinBox::valueChanged),
-            this, &TaskAttacher::onAttachmentOffsetRollChanged);
+        this, &TaskAttacher::onAttachmentOffsetRollChanged);
     connect(ui->checkBoxFlip, &QCheckBox::toggled,
-            this, &TaskAttacher::onCheckFlip);
+        this, &TaskAttacher::onCheckFlip);
     connect(ui->buttonRef1, &QPushButton::clicked,
-            this, &TaskAttacher::onButtonRef1);
+        this, &TaskAttacher::onButtonRef1);
     connect(ui->lineRef1, &QLineEdit::textEdited,
-            this, &TaskAttacher::onRefName1);
+        this, &TaskAttacher::onRefName1);
     connect(ui->buttonRef2, &QPushButton::clicked,
-            this, &TaskAttacher::onButtonRef2);
+        this, &TaskAttacher::onButtonRef2);
     connect(ui->lineRef2, &QLineEdit::textEdited,
-            this, &TaskAttacher::onRefName2);
+        this, &TaskAttacher::onRefName2);
     connect(ui->buttonRef3, &QPushButton::clicked,
-            this, &TaskAttacher::onButtonRef3);
+        this, &TaskAttacher::onButtonRef3);
     connect(ui->lineRef3, &QLineEdit::textEdited,
-            this, &TaskAttacher::onRefName3);
+        this, &TaskAttacher::onRefName3);
     connect(ui->buttonRef4, &QPushButton::clicked,
-            this, &TaskAttacher::onButtonRef4);
+        this, &TaskAttacher::onButtonRef4);
     connect(ui->lineRef4, &QLineEdit::textEdited,
-            this, &TaskAttacher::onRefName4);
+        this, &TaskAttacher::onRefName4);
     connect(ui->listOfModes, &QListWidget::itemSelectionChanged,
-            this, &TaskAttacher::onModeSelect);
+        this, &TaskAttacher::onModeSelect);
     // clang-format on
 
     this->groupLayout()->addWidget(proxy);
@@ -205,19 +201,20 @@ TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject *ViewProvider, QWidge
         this->iActiveRef = 0;
     else
         this->iActiveRef = -1;
-    if (pcAttach->AttachmentSupport.getSize() == 0){
+    if (pcAttach->AttachmentSupport.getSize() == 0) {
         autoNext = true;
-    } else {
+    }
+    else {
         autoNext = false;
     }
 
-    ui->attachmentOffsetX->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Base.x")));
-    ui->attachmentOffsetY->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Base.y")));
-    ui->attachmentOffsetZ->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Base.z")));
+    ui->attachmentOffsetX->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Base.x")));
+    ui->attachmentOffsetY->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Base.y")));
+    ui->attachmentOffsetZ->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Base.z")));
 
-    ui->attachmentOffsetYaw->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Yaw")));
-    ui->attachmentOffsetPitch->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Pitch")));
-    ui->attachmentOffsetRoll->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Roll")));
+    ui->attachmentOffsetYaw->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Yaw")));
+    ui->attachmentOffsetPitch->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Pitch")));
+    ui->attachmentOffsetRoll->bind(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Roll")));
 
     visibilityAutomation(true);
     updateAttachmentOffsetUI();
@@ -234,6 +231,8 @@ TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject *ViewProvider, QWidge
     Gui::Document* document = Gui::Application::Instance->getDocument(ViewProvider->getObject()->getDocument());
     connectDelObject = document->signalDeletedObject.connect(bnd1);
     connectDelDocument = document->signalDeleteDocument.connect(bnd2);
+
+    handleInitialSelection();
 }
 
 TaskAttacher::~TaskAttacher()
@@ -293,10 +292,11 @@ void TaskAttacher::updateReferencesUI()
     pcAttach->attacher().suggestMapModes(this->lastSuggestResult);
 
     if (this->lastSuggestResult.message != SuggestResult::srOK) {
-        if(!this->lastSuggestResult.nextRefTypeHint.empty()){
+        if (!this->lastSuggestResult.nextRefTypeHint.empty()) {
             //message = "Need more references";
         }
-    } else {
+    }
+    else {
         completed = true;
     }
 
@@ -314,24 +314,29 @@ bool TaskAttacher::updatePreview()
     Part::AttachExtension* pcAttach = ViewProvider->getObject()->getExtensionByType<Part::AttachExtension>();
     QString errMessage;
     bool attached = false;
-    try{
+    try {
         attached = pcAttach->positionBySupport();
-    } catch (Base::Exception &err){
+    }
+    catch (Base::Exception& err) {
         errMessage = QCoreApplication::translate("Exception", err.what());
-    } catch (Standard_Failure &err){
+    }
+    catch (Standard_Failure& err) {
         errMessage = tr("OCC error: %1").arg(QString::fromLatin1(err.GetMessageString()));
-    } catch (...) {
+    }
+    catch (...) {
         errMessage = tr("unknown error");
     }
-    if (errMessage.length()>0){
+    if (errMessage.length() > 0) {
         ui->message->setText(tr("Attachment mode failed: %1").arg(errMessage));
         ui->message->setStyleSheet(QString::fromLatin1("QLabel{color: red;}"));
-    } else {
-        if (!attached){
+    }
+    else {
+        if (!attached) {
             ui->message->setText(tr("Not attached"));
             ui->message->setStyleSheet(QString());
-        } else {
-            std::vector<QString> strs = AttacherGui::getUIStrings(pcAttach->attacher().getTypeId(),eMapMode(pcAttach->MapMode.getValue()));
+        }
+        else {
+            std::vector<QString> strs = AttacherGui::getUIStrings(pcAttach->attacher().getTypeId(), eMapMode(pcAttach->MapMode.getValue()));
             ui->message->setText(tr("Attached with mode %1").arg(strs[0]));
             ui->message->setStyleSheet(QString::fromLatin1("QLabel{color: green;}"));
         }
@@ -345,47 +350,193 @@ bool TaskAttacher::updatePreview()
 
 QLineEdit* TaskAttacher::getLine(unsigned idx)
 {
-    switch(idx) {
-        case 0: return ui->lineRef1;
-        case 1: return ui->lineRef2;
-        case 2: return ui->lineRef3;
-        case 3: return ui->lineRef4;
-        default: return nullptr;
+    switch (idx) {
+    case 0: return ui->lineRef1;
+    case 1: return ui->lineRef2;
+    case 2: return ui->lineRef3;
+    case 3: return ui->lineRef4;
+    default: return nullptr;
     }
 }
 
+void TaskAttacher::findCorrectObjAndSubInThisContext(App::DocumentObject*& rootObj, std::string& sub)
+{
+    // The reference that we store must take into account the hierarchy of geoFeatures. For example:
+    // - Part
+    // - - Cube
+    // - Sketch
+    // if sketch is attached to Cube.Face1 then it must store Part:Cube.Face3 as Sketch is outside of Part.
+    // - Part
+    // - - Cube
+    // - - Sketch
+    // In this example it must store Cube:Face3 because Sketch is inside Part, sibling of Cube.
+    // So placement of Part is already taken into account.
+    // - Part1
+    // - - Part2
+    // - - - Cube
+    // - - Sketch
+    // In this example it must store Part2:Cube.Face3 since Part1 is already taken into account.
+    // - Part1
+    // - - Part2
+    // - - - Cube
+    // - - Part3
+    // - - - Sketch
+    // In this example it's not possible because Sketch has Part3 placement. So it should be rejected
+    // So we need to take the selection object and subname, and process them to get the correct obj/sub based
+    // on attached and attaching objects positions.
+
+    std::vector<std::string> names = Base::Tools::splitSubName(sub);
+    if (!rootObj || names.size() < 2) {
+        return;
+    }
+    names.insert(names.begin(), rootObj->getNameInDocument());
+
+    App::Document* doc = rootObj->getDocument();
+    App::DocumentObject* attachingObj = ViewProvider->getObject(); // Attaching object
+    App::DocumentObject* subObj = rootObj->getSubObject(sub.c_str()); // Object being attached.
+    if (!subObj || subObj == rootObj) {
+        // Case of root object. We don't need to modify it.
+        return;
+    }
+    if (subObj == attachingObj) {
+        //prevent self-referencing
+        rootObj = nullptr;
+        return;
+    }
+
+    // Check if attachingObj is a root object. if so we keep the full path.
+    auto* group = App::GeoFeatureGroupExtension::getGroupOfObject(attachingObj);
+    if (!group) {
+        if (attachingObj->getDocument() != rootObj->getDocument()) {
+            // If it's not in same document then it's not a good selection
+            rootObj = nullptr;
+        }
+        // if it's same document we keep the rootObj and sub unchanged.
+        return;
+    }
+
+    bool groupPassed = false;
+    for (size_t i = 0; i < names.size(); ++i) {
+        App::DocumentObject* obj = doc->getObject(names[i].c_str());
+        if (!obj) {
+            Base::Console().TranslatedUserError("TaskAttacher",
+                "Unsuitable selection: '%s' cannot be attached to '%s' from within it's group '%s'.\n",
+                attachingObj->getFullLabel(), subObj->getFullLabel(), group->getFullLabel());
+            rootObj = nullptr;
+            return;
+        }
+
+        if (groupPassed) {
+            rootObj = obj;
+
+            // Rebuild 'sub' starting from the next element after the current 'name'
+            sub = "";
+            for (size_t j = i + 1; j < names.size(); ++j) {
+                sub += names[j];
+                if (j != names.size() - 1) {
+                    sub += ".";  // Add a period between elements
+                }
+            }
+            return;
+        }
+
+        // In case the attaching object is in a link to a part.
+        // For instance : 
+        // - Part1
+        // - - LinkToPart2
+        // - - - Cube
+        // - - - Sketch
+        obj = obj->getLinkedObject();
+
+        if (obj == group) {
+            groupPassed = true;
+        }
+    }
+
+    // if we reach this point it means that attaching object's group is outside of
+    // the scope of the attached object. For instance: 
+    // - Part1
+    // - - Part2
+    // - - - Cube
+    // - - Part3
+    // - - - Sketch
+    // In this case the selection is not acceptable.
+    rootObj = nullptr;
+}
+
+void TaskAttacher::handleInitialSelection()
+{
+    // We handle initial selection only if it is not attached yet.
+    App::DocumentObject* obj = ViewProvider->getObject();
+    Part::AttachExtension* pcAttach = obj->getExtensionByType<Part::AttachExtension>();
+    std::vector<App::DocumentObject*> refs = pcAttach->AttachmentSupport.getValues();
+
+    if (!refs.empty()) {
+        return;
+    }
+    std::vector<SubAndObjName> subAndObjNamePairs;
+
+    auto sel = Gui::Selection().getSelectionEx("",
+        App::DocumentObject::getClassTypeId(), Gui::ResolveMode::NoResolve);
+    for (auto& selObj : sel) {
+        std::vector<std::string> subs = selObj.getSubNames();
+        std::string objName = selObj.getFeatName();
+        for (auto& sub : subs) {
+            SubAndObjName objSubName = { objName, sub };
+            subAndObjNamePairs.push_back(objSubName);
+        }
+    }
+    addToReference(subAndObjNamePairs);
+}
+
 void TaskAttacher::onSelectionChanged(const Gui::SelectionChanges& msg)
 {
-    if (!ViewProvider)
+    if (!ViewProvider) {
         return;
+    }
 
     if (msg.Type == Gui::SelectionChanges::AddSelection) {
-        if (iActiveRef < 0)
-            return;
+        SubAndObjName pair = { msg.pObjectName, msg.pSubName };
+        addToReference(pair);
+    }
+}
 
-        // Note: The validity checking has already been done in ReferenceSelection.cpp
-        Part::AttachExtension* pcAttach = ViewProvider->getObject()->getExtensionByType<Part::AttachExtension>();
+void TaskAttacher::addToReference(const std::vector<SubAndObjName>& pairs)
+{
+    if (iActiveRef < 0) {
+        return;
+    }
+
+    // Note: The validity checking has already been done in ReferenceSelection.cpp
+    App::DocumentObject* obj = ViewProvider->getObject();
+    Part::AttachExtension* pcAttach = obj->getExtensionByType<Part::AttachExtension>();
+
+    for (auto& pair : pairs) {
         std::vector<App::DocumentObject*> refs = pcAttach->AttachmentSupport.getValues();
         std::vector<std::string> refnames = pcAttach->AttachmentSupport.getSubValues();
-        App::DocumentObject* selObj = ViewProvider->getObject()->getDocument()->getObject(msg.pObjectName);
-        if (!selObj || selObj == ViewProvider->getObject())//prevent self-referencing
-            return;
 
-        std::string subname = msg.pSubName;
+        App::DocumentObject* selObj = obj->getDocument()->getObject(pair.objName.c_str());
+        std::string subname = pair.subName;
+        findCorrectObjAndSubInThisContext(selObj, subname);
+        if (!selObj) {
+            return;
+        }
 
         // Remove subname for planes and datum features
-        if (selObj->isDerivedFrom<App::DatumElement>() ||
-            selObj->isDerivedFrom<Part::Datum>())
+        if (selObj->isDerivedFrom<App::DatumElement>() || selObj->isDerivedFrom<Part::Datum>()) {
             subname = "";
+        }
 
         // eliminate duplicate selections
-        for (size_t r = 0; r < refs.size(); r++)
-            if ((refs[r] == selObj) && (refnames[r] == subname))
+        for (size_t r = 0; r < refs.size(); r++) {
+            if ((refs[r] == selObj) && (refnames[r] == subname)) {
                 return;
+            }
+        }
 
-        if (autoNext && iActiveRef > 0 && iActiveRef == static_cast<int>(refnames.size())){
-            if (refs[iActiveRef-1] == selObj
-                && refnames[iActiveRef-1].length() != 0 && subname.length() == 0){
+        if (autoNext && iActiveRef > 0 && iActiveRef == static_cast<int>(refnames.size())) {
+            if (refs[iActiveRef - 1] == selObj
+                && refnames[iActiveRef - 1].length() != 0 && subname.length() == 0) {
                 //A whole object was selected by clicking it twice. Fill it
                 //into previous reference, where a sub-named reference filled by
                 //the first click is already stored.
@@ -396,31 +547,13 @@ void TaskAttacher::onSelectionChanged(const Gui::SelectionChanges& msg)
         if (iActiveRef < static_cast<int>(refs.size())) {
             refs[iActiveRef] = selObj;
             refnames[iActiveRef] = subname;
-        } else {
+        }
+        else {
             refs.push_back(selObj);
             refnames.push_back(subname);
         }
 
-        //bool error = false;
-        try {
-            pcAttach->AttachmentSupport.setValues(refs, refnames);
-            updateListOfModes();
-            eMapMode mmode = getActiveMapMode();//will be mmDeactivated, if selected or if no modes are available
-            if(mmode == mmDeactivated){
-                //error = true;
-                this->completed = false;
-            } else {
-                this->completed = true;
-            }
-            pcAttach->MapMode.setValue(mmode);
-            selectMapMode(mmode);
-            updatePreview();
-        }
-        catch(Base::Exception& e) {
-            //error = true;
-            ui->message->setText(QCoreApplication::translate("Exception", e.what()));
-            ui->message->setStyleSheet(QString::fromLatin1("QLabel{color: red;}"));
-        }
+        pcAttach->AttachmentSupport.setValues(refs, refnames);
 
         QLineEdit* line = getLine(iActiveRef);
         if (line) {
@@ -431,17 +564,43 @@ void TaskAttacher::onSelectionChanged(const Gui::SelectionChanges& msg)
         }
 
         if (autoNext) {
-            if (iActiveRef == -1){
+            if (iActiveRef == -1) {
                 //nothing to do
-            } else if (iActiveRef == 4 || this->lastSuggestResult.nextRefTypeHint.empty()){
+            }
+            else if (iActiveRef == 4 || this->lastSuggestResult.nextRefTypeHint.empty()) {
                 iActiveRef = -1;
-            } else {
+            }
+            else {
                 iActiveRef++;
             }
         }
-
-        updateReferencesUI();
     }
+
+    try {
+        updateListOfModes();
+        eMapMode mmode = getActiveMapMode();  //will be mmDeactivated, if selected or if no modes are available
+        if (mmode == mmDeactivated) {
+            //error = true;
+            this->completed = false;
+        }
+        else {
+            this->completed = true;
+        }
+        pcAttach->MapMode.setValue(mmode);
+        selectMapMode(mmode);
+        updatePreview();
+    }
+    catch (Base::Exception& e) {
+        ui->message->setText(QCoreApplication::translate("Exception", e.what()));
+        ui->message->setStyleSheet(QString::fromLatin1("QLabel{color: red;}"));
+    }
+
+    updateReferencesUI();
+}
+
+void TaskAttacher::addToReference(SubAndObjName pair)
+{
+    addToReference({ pair });
 }
 
 void TaskAttacher::onAttachmentOffsetChanged(double /*val*/, int idx)
@@ -462,17 +621,17 @@ void TaskAttacher::onAttachmentOffsetChanged(double /*val*/, int idx)
     if (idx == 2) {
         pos.z = ui->attachmentOffsetZ->value().getValueAs(Base::Quantity::MilliMetre);
     }
-    if (idx >= 0  && idx <= 2){
+    if (idx >= 0 && idx <= 2) {
         pl.setPosition(pos);
     }
 
-    if (idx >= 3  &&  idx <= 5){
+    if (idx >= 3 && idx <= 5) {
         double yaw, pitch, roll;
         yaw = ui->attachmentOffsetYaw->value().getValueAs(Base::Quantity::Degree);
         pitch = ui->attachmentOffsetPitch->value().getValueAs(Base::Quantity::Degree);
         roll = ui->attachmentOffsetRoll->value().getValueAs(Base::Quantity::Degree);
         Base::Rotation rot;
-        rot.setYawPitchRoll(yaw,pitch,roll);
+        rot.setYawPitchRoll(yaw, pitch, roll);
         pl.setRotation(rot);
     }
 
@@ -526,7 +685,8 @@ void TaskAttacher::onButtonRef(const bool checked, unsigned idx)
     if (checked) {
         Gui::Selection().clearSelection();
         iActiveRef = idx;
-    } else {
+    }
+    else {
         iActiveRef = -1;
     }
     updateRefButton(0);
@@ -619,12 +779,15 @@ void TaskAttacher::onRefName(const QString& text, unsigned idx)
     if (obj->isDerivedFrom<App::Plane>()) {
         // everything is OK (we assume a Part can only have exactly 3 App::Plane objects located at the base of the feature tree)
         subElement.clear();
-    } else if (obj->isDerivedFrom<App::Line>()) {
+    }
+    else if (obj->isDerivedFrom<App::Line>()) {
         // everything is OK (we assume a Part can only have exactly 3 App::Line objects located at the base of the feature tree)
         subElement.clear();
-    } else if (obj->isDerivedFrom<Part::Datum>()) {
+    }
+    else if (obj->isDerivedFrom<Part::Datum>()) {
         subElement.clear();
-    } else {
+    }
+    else {
         // TODO: check validity of the text that was entered: Does subElement actually reference to an element on the obj?
 
         auto getSubshapeName = [](const QString& part) -> std::string {
@@ -672,7 +835,8 @@ void TaskAttacher::onRefName(const QString& text, unsigned idx)
     if (idx < refs.size()) {
         refs[idx] = obj;
         refnames[idx] = subElement;
-    } else {
+    }
+    else {
         refs.push_back(obj);
         refnames.emplace_back(subElement);
     }
@@ -690,12 +854,12 @@ void TaskAttacher::updateRefButton(int idx)
         return;
 
     QAbstractButton* b;
-    switch(idx){
-        case 0: b = ui->buttonRef1; break;
-        case 1: b = ui->buttonRef2; break;
-        case 2: b = ui->buttonRef3; break;
-        case 3: b = ui->buttonRef4; break;
-        default: throw Base::IndexError("button index out of range");
+    switch (idx) {
+    case 0: b = ui->buttonRef1; break;
+    case 1: b = ui->buttonRef2; break;
+    case 2: b = ui->buttonRef3; break;
+    case 3: b = ui->buttonRef4; break;
+    default: throw Base::IndexError("button index out of range");
     }
 
     Part::AttachExtension* pcAttach = ViewProvider->getObject()->getExtensionByType<Part::AttachExtension>();
@@ -713,10 +877,12 @@ void TaskAttacher::updateRefButton(int idx)
 
     if (iActiveRef == idx) {
         b->setText(tr("Selecting..."));
-    } else if (idx < static_cast<int>(this->lastSuggestResult.references_Types.size())){
+    }
+    else if (idx < static_cast<int>(this->lastSuggestResult.references_Types.size())) {
         b->setText(AttacherGui::getShapeTypeText(this->lastSuggestResult.references_Types[idx]));
-    } else {
-        b->setText(tr("Reference%1").arg(idx+1));
+    }
+    else {
+        b->setText(tr("Reference%1").arg(idx + 1));
     }
 }
 
@@ -740,9 +906,9 @@ void TaskAttacher::updateAttachmentOffsetUI()
     ui->attachmentOffsetPitch->blockSignals(bBlock);
     ui->attachmentOffsetRoll->blockSignals(bBlock);
 
-    ui->attachmentOffsetX->setValue(Base::Quantity(pos.x,Base::Unit::Length));
-    ui->attachmentOffsetY->setValue(Base::Quantity(pos.y,Base::Unit::Length));
-    ui->attachmentOffsetZ->setValue(Base::Quantity(pos.z,Base::Unit::Length));
+    ui->attachmentOffsetX->setValue(Base::Quantity(pos.x, Base::Unit::Length));
+    ui->attachmentOffsetY->setValue(Base::Quantity(pos.y, Base::Unit::Length));
+    ui->attachmentOffsetZ->setValue(Base::Quantity(pos.z, Base::Unit::Length));
     ui->attachmentOffsetYaw->setValue(yaw);
     ui->attachmentOffsetPitch->setValue(pitch);
     ui->attachmentOffsetRoll->setValue(roll);
@@ -750,13 +916,13 @@ void TaskAttacher::updateAttachmentOffsetUI()
     auto expressions = ViewProvider->getObject()->ExpressionEngine.getExpressions();
     bool bRotationBound = false;
     bRotationBound = bRotationBound ||
-            expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Angle"))) != expressions.end();
+        expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Angle"))) != expressions.end();
     bRotationBound = bRotationBound ||
-            expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Axis.x"))) != expressions.end();
+        expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Axis.x"))) != expressions.end();
     bRotationBound = bRotationBound ||
-            expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Axis.y"))) != expressions.end();
+        expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Axis.y"))) != expressions.end();
     bRotationBound = bRotationBound ||
-            expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(),std::string("AttachmentOffset.Rotation.Axis.z"))) != expressions.end();
+        expressions.find(App::ObjectIdentifier::parse(ViewProvider->getObject(), std::string("AttachmentOffset.Rotation.Axis.z"))) != expressions.end();
 
     ui->attachmentOffsetYaw->setEnabled(!bRotationBound);
     ui->attachmentOffsetPitch->setEnabled(!bRotationBound);
@@ -794,22 +960,23 @@ void TaskAttacher::updateListOfModes()
     this->lastSuggestResult.bestFitMode = mmDeactivated;
     size_t lastValidModeItemIndex = mmDummy_NumberOfModes;
 
-    if (pcAttach->AttachmentSupport.getSize() > 0){
+    if (pcAttach->AttachmentSupport.getSize() > 0) {
         pcAttach->attacher().suggestMapModes(this->lastSuggestResult);
         modesInList = this->lastSuggestResult.allApplicableModes;
         modesInList.insert(modesInList.begin(), mmDeactivated); // always have the option to choose Deactivated mode
 
         //add reachable modes to the list, too, but gray them out (using lastValidModeItemIndex, later)
-        lastValidModeItemIndex = modesInList.size()-1;
-        for(std::pair<const eMapMode, refTypeStringList> &rm: this->lastSuggestResult.reachableModes){
+        lastValidModeItemIndex = modesInList.size() - 1;
+        for (std::pair<const eMapMode, refTypeStringList>& rm : this->lastSuggestResult.reachableModes) {
             modesInList.push_back(rm.first);
         }
-    } else {
+    }
+    else {
         //no references - display all modes
         modesInList.clear();
         modesInList.push_back(mmDeactivated);
 
-        for(  int mmode = 0  ;  mmode < mmDummy_NumberOfModes  ;  mmode++){
+        for (int mmode = 0; mmode < mmDummy_NumberOfModes; mmode++) {
             if (pcAttach->attacher().modeEnabled[mmode])
                 modesInList.push_back(eMapMode(mmode));
         }
@@ -820,40 +987,42 @@ void TaskAttacher::updateListOfModes()
     ui->listOfModes->clear();
     QListWidgetItem* iSelect = nullptr;
     if (!modesInList.empty()) {
-        for (size_t i = 0  ;  i < modesInList.size()  ;  ++i){
+        for (size_t i = 0; i < modesInList.size(); ++i) {
             eMapMode mmode = modesInList[i];
-            std::vector<QString> mstr = AttacherGui::getUIStrings(pcAttach->attacher().getTypeId(),mmode);
+            std::vector<QString> mstr = AttacherGui::getUIStrings(pcAttach->attacher().getTypeId(), mmode);
             ui->listOfModes->addItem(mstr[0]);
             QListWidgetItem* item = ui->listOfModes->item(i);
             QString tooltip = mstr[1];
 
             if (mmode != mmDeactivated) {
                 tooltip += QString::fromLatin1("\n\n%1\n%2")
-                        .arg(tr("Reference combinations:"),
-                             AttacherGui::getRefListForMode(pcAttach->attacher(),mmode).join(QString::fromLatin1("\n")));
+                    .arg(tr("Reference combinations:"),
+                        AttacherGui::getRefListForMode(pcAttach->attacher(), mmode).join(QString::fromLatin1("\n")));
             }
             item->setToolTip(tooltip);
 
             if (mmode == curMode && curMode != mmDeactivated)
                 iSelect = ui->listOfModes->item(i);
-            if (i > lastValidModeItemIndex){
+            if (i > lastValidModeItemIndex) {
                 //potential mode - can be reached by selecting more stuff
                 item->setFlags(item->flags() & ~(Qt::ItemFlag::ItemIsEnabled | Qt::ItemFlag::ItemIsSelectable));
 
-                refTypeStringList &extraRefs = this->lastSuggestResult.reachableModes[mmode];
-                if (extraRefs.size() == 1){
+                refTypeStringList& extraRefs = this->lastSuggestResult.reachableModes[mmode];
+                if (extraRefs.size() == 1) {
                     QStringList buf;
-                    for(eRefType rt : extraRefs[0]){
+                    for (eRefType rt : extraRefs[0]) {
                         buf.append(AttacherGui::getShapeTypeText(rt));
                     }
                     item->setText(tr("%1 (add %2)").arg(
-                                      item->text(),
-                                      buf.join(QString::fromLatin1("+"))
-                                      ));
-                } else {
+                        item->text(),
+                        buf.join(QString::fromLatin1("+"))
+                    ));
+                }
+                else {
                     item->setText(tr("%1 (add more references)").arg(item->text()));
                 }
-            } else if (mmode == this->lastSuggestResult.bestFitMode){
+            }
+            else if (mmode == this->lastSuggestResult.bestFitMode) {
                 //suggested mode - make bold
                 QFont fnt = item->font();
                 fnt.setBold(true);
@@ -873,7 +1042,7 @@ void TaskAttacher::updateListOfModes()
 void TaskAttacher::selectMapMode(eMapMode mmode) {
     ui->listOfModes->blockSignals(true);
 
-    for (size_t i = 0;  i < modesInList.size(); ++i) {
+    for (size_t i = 0; i < modesInList.size(); ++i) {
         if (modesInList[i] == mmode) {
             ui->listOfModes->item(i)->setSelected(true);
         }
@@ -910,7 +1079,7 @@ void TaskAttacher::onRefName3(const QString& text)
     onRefName(text, 2);
 }
 
-void TaskAttacher::onRefName4(const QString &text)
+void TaskAttacher::onRefName4(const QString& text)
 {
     onRefName(text, 3);
 }
@@ -920,7 +1089,7 @@ bool TaskAttacher::getFlip() const
     return ui->checkBoxFlip->isChecked();
 }
 
-void TaskAttacher::changeEvent(QEvent *e)
+void TaskAttacher::changeEvent(QEvent* e)
 {
     TaskBox::changeEvent(e);
     if (e->type() == QEvent::LanguageChange) {
@@ -958,11 +1127,11 @@ void TaskAttacher::changeEvent(QEvent *e)
 
 void TaskAttacher::visibilityAutomation(bool opening_not_closing)
 {
-    auto defvisfunc = [] (bool opening_not_closing,
-                          const std::string &postfix,
-                          Gui::ViewProviderDocumentObject* vp,
-                          App::DocumentObject *editObj,
-                          const std::string& editSubName) {
+    auto defvisfunc = [](bool opening_not_closing,
+        const std::string& postfix,
+        Gui::ViewProviderDocumentObject* vp,
+        App::DocumentObject* editObj,
+        const std::string& editSubName) {
         if (opening_not_closing) {
             QString code = QString::fromLatin1(
                 "import Show\n"
@@ -981,19 +1150,19 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
                 "\t\tif len(tvObj.AttachmentSupport) > 0:\n"
                 "\t\t\t_tv_%4.show([lnk[0] for lnk in tvObj.AttachmentSupport])\n"
                 "del(tvObj)"
-                ).arg(
-                    QString::fromLatin1(Gui::Command::getObjectCmd(vp->getObject()).c_str()),
-                    QString::fromLatin1(Gui::Command::getObjectCmd(editObj).c_str()),
-                    QString::fromLatin1(editSubName.c_str()),
-                    QString::fromLatin1(postfix.c_str()));
-            Gui::Command::runCommand(Gui::Command::Gui,code.toLatin1().constData());
+            ).arg(
+                QString::fromLatin1(Gui::Command::getObjectCmd(vp->getObject()).c_str()),
+                QString::fromLatin1(Gui::Command::getObjectCmd(editObj).c_str()),
+                QString::fromLatin1(editSubName.c_str()),
+                QString::fromLatin1(postfix.c_str()));
+            Gui::Command::runCommand(Gui::Command::Gui, code.toLatin1().constData());
         }
         else if (!postfix.empty()) {
             QString code = QString::fromLatin1(
                 "_tv_%1.restore()\n"
                 "del(_tv_%1)"
-                ).arg(QString::fromLatin1(postfix.c_str()));
-            Gui::Command::runCommand(Gui::Command::Gui,code.toLatin1().constData());
+            ).arg(QString::fromLatin1(postfix.c_str()));
+            Gui::Command::runCommand(Gui::Command::Gui, code.toLatin1().constData());
         }
     };
 
@@ -1009,18 +1178,19 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
             return;
 
         auto editDoc = Gui::Application::Instance->editDocument();
-        App::DocumentObject *editObj = ViewProvider->getObject();
+        App::DocumentObject* editObj = ViewProvider->getObject();
         std::string editSubName;
         auto sels = Gui::Selection().getSelection(nullptr, Gui::ResolveMode::NoResolve, true);
-        if(!sels.empty() && sels[0].pResolvedObject
-                       && sels[0].pResolvedObject->getLinkedObject()==editObj)
+        if (!sels.empty() && sels[0].pResolvedObject
+            && sels[0].pResolvedObject->getLinkedObject() == editObj)
         {
             editObj = sels[0].pObject;
             editSubName = sels[0].SubName;
-        } else {
-            ViewProviderDocumentObject *editVp = nullptr;
+        }
+        else {
+            ViewProviderDocumentObject* editVp = nullptr;
             if (editDoc) {
-                editDoc->getInEdit(&editVp,&editSubName);
+                editDoc->getInEdit(&editVp, &editSubName);
                 if (editVp)
                     editObj = editVp->getObject();
             }
@@ -1029,7 +1199,7 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
         try {
             visAutoFunc(opening_not_closing, ObjectName, ViewProvider, editObj, editSubName);
         }
-        catch (const Base::Exception &e){
+        catch (const Base::Exception& e) {
             e.ReportException();
         }
         catch (const Py::Exception&) {
@@ -1043,7 +1213,7 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
             objName.swap(ObjectName);
             visAutoFunc(opening_not_closing, objName, nullptr, nullptr, std::string());
         }
-        catch (Base::Exception &e) {
+        catch (Base::Exception& e) {
             e.ReportException();
         }
     }
@@ -1054,14 +1224,14 @@ void TaskAttacher::visibilityAutomation(bool opening_not_closing)
 // TaskDialog
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
-TaskDlgAttacher::TaskDlgAttacher(Gui::ViewProviderDocumentObject *ViewProvider, bool createBox)
-    : TaskDialog(),ViewProvider(ViewProvider), parameter(nullptr)
+TaskDlgAttacher::TaskDlgAttacher(Gui::ViewProviderDocumentObject* ViewProvider, bool createBox)
+    : TaskDialog(), ViewProvider(ViewProvider), parameter(nullptr)
 {
     assert(ViewProvider);
     setDocumentName(ViewProvider->getDocument()->getDocument()->getName());
 
-    if(createBox) {
-        parameter  = new TaskAttacher(ViewProvider, nullptr, QString(), tr("Attachment"));
+    if (createBox) {
+        parameter = new TaskAttacher(ViewProvider, nullptr, QString(), tr("Attachment"));
         Content.push_back(parameter);
     }
 }
@@ -1096,11 +1266,11 @@ bool TaskDlgAttacher::accept()
 
         //DeepSOIC: changed this to heavily rely on dialog constantly updating feature properties
         //if (pcAttach->AttachmentOffset.isTouched()){
-            Base::Placement plm = pcAttach->AttachmentOffset.getValue();
-            double yaw, pitch, roll;
-            plm.getRotation().getYawPitchRoll(yaw,pitch,roll);
-            Gui::cmdAppObjectArgs(obj, "AttachmentOffset = App.Placement(App.Vector(%.10f, %.10f, %.10f),  App.Rotation(%.10f, %.10f, %.10f))",
-                                  plm.getPosition().x, plm.getPosition().y, plm.getPosition().z, yaw, pitch, roll);
+        Base::Placement plm = pcAttach->AttachmentOffset.getValue();
+        double yaw, pitch, roll;
+        plm.getRotation().getYawPitchRoll(yaw, pitch, roll);
+        Gui::cmdAppObjectArgs(obj, "AttachmentOffset = App.Placement(App.Vector(%.10f, %.10f, %.10f),  App.Rotation(%.10f, %.10f, %.10f))",
+            plm.getPosition().x, plm.getPosition().y, plm.getPosition().z, yaw, pitch, roll);
         //}
 
         Gui::cmdAppObjectArgs(obj, "MapReversed = %s", pcAttach->MapReversed.getValue() ? "True" : "False");

src/Mod/Part/Gui/TaskAttacher.h

@@ -113,6 +113,15 @@ private:
     void updateRefButton(int idx);
     void updateAttachmentOffsetUI();
 
+    void findCorrectObjAndSubInThisContext(App::DocumentObject*& obj, std::string& sub);
+    void handleInitialSelection();
+    struct SubAndObjName {
+        std::string objName;
+        std::string subName;
+    };
+    void addToReference(SubAndObjName  pair);
+    void addToReference(const std::vector<SubAndObjName >& pairs);
+
     /**
      * @brief updateListOfModes Fills the mode list with modes that apply to
      * current set of references. Maintains selection when possible.

src/Mod/Part/Gui/ViewProviderAttachExtension.cpp

@@ -113,6 +113,10 @@ void ViewProviderAttachExtension::extensionSetupContextMenu(QMenu* menu, QObject
 
 void ViewProviderAttachExtension::showAttachmentEditor()
 {
+    if (Gui::Control().activeDialog()) {
+        Gui::Control().closeDialog();
+    }
+
     // See PropertyEnumAttacherItem::openTask()
     Gui::TaskView::TaskDialog* dlg = Gui::Control().activeDialog();
     TaskDlgAttacher* task;

src/Mod/Part/Gui/ViewProviderAttachExtension.h

@@ -44,7 +44,6 @@ public:
     void extensionUpdateData(const App::Property*) override;
     void extensionSetupContextMenu(QMenu*, QObject*, const char*) override;
 
-private:
     void showAttachmentEditor();
 };
 

src/Mod/Part/Gui/ViewProviderDatum.cpp

@@ -0,0 +1,94 @@
+/***************************************************************************
+ *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#include "PreCompiled.h"
+
+#ifndef _PreComp_
+#endif
+
+#include <App/Document.h>
+#include <App/DocumentObjectGroup.h>
+#include <Gui/Application.h>
+#include <Gui/Command.h>
+#include <Gui/Control.h>
+#include <Gui/View3DInventor.h>
+#include <Gui/View3DInventorViewer.h>
+
+#include "ViewProviderDatum.h"
+
+
+using namespace PartGui;
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(PartGui::ViewProviderLine, Gui::ViewProviderLine)
+
+ViewProviderLine::ViewProviderLine()
+{
+    PartGui::ViewProviderAttachExtension::initExtension(this);
+}
+
+bool ViewProviderLine::doubleClicked()
+{
+    showAttachmentEditor();
+    return true;
+}
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(PartGui::ViewProviderPlane, Gui::ViewProviderPlane)
+
+ViewProviderPlane::ViewProviderPlane()
+{
+    PartGui::ViewProviderAttachExtension::initExtension(this);
+}
+
+bool ViewProviderPlane::doubleClicked()
+{
+    showAttachmentEditor();
+    return true;
+}
+
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(PartGui::ViewProviderPoint, Gui::ViewProviderPoint)
+
+ViewProviderPoint::ViewProviderPoint()
+{
+    PartGui::ViewProviderAttachExtension::initExtension(this);
+}
+
+bool ViewProviderPoint::doubleClicked()
+{
+    showAttachmentEditor();
+    return true;
+}
+
+
+PROPERTY_SOURCE_WITH_EXTENSIONS(PartGui::ViewProviderLCS, Gui::ViewProviderCoordinateSystem)
+
+ViewProviderLCS::ViewProviderLCS()
+{
+    PartGui::ViewProviderAttachExtension::initExtension(this);
+}
+
+bool ViewProviderLCS::doubleClicked()
+{
+    showAttachmentEditor();
+    return true;
+}

src/Mod/Part/Gui/ViewProviderDatum.h

@@ -0,0 +1,84 @@
+/***************************************************************************
+ *   Copyright (c) 2024 Ondsel (PL Boyer) <development@ondsel.com>         *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#ifndef PARTGUI_ViewProviderDatum_H
+#define PARTGUI_ViewProviderDatum_H
+
+#include <Gui/ViewProviderLine.h>
+#include <Gui/ViewProviderPlane.h>
+#include <Gui/ViewProviderPoint.h>
+#include <Gui/ViewProviderCoordinateSystem.h>
+#include <QCoreApplication>
+
+#include <Mod/Part/Gui/ViewProviderAttachExtension.h>
+
+namespace PartGui {
+
+class PartGuiExport ViewProviderLine : public Gui::ViewProviderLine, PartGui::ViewProviderAttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(PartGui::ViewProviderLine);
+
+public:
+    ViewProviderLine();
+    ~ViewProviderLine() override = default;
+
+    bool doubleClicked() override;
+};
+
+class PartGuiExport ViewProviderPlane : public Gui::ViewProviderPlane, PartGui::ViewProviderAttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(PartGui::ViewProviderPlane);
+
+public:
+    ViewProviderPlane();
+    ~ViewProviderPlane() override = default;
+
+    bool doubleClicked() override;
+};
+
+class PartGuiExport ViewProviderPoint : public Gui::ViewProviderPoint, PartGui::ViewProviderAttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(PartGui::ViewProviderPoint);
+
+public:
+    ViewProviderPoint();
+    ~ViewProviderPoint() override = default;
+
+    bool doubleClicked() override;
+};
+
+class PartGuiExport ViewProviderLCS : public Gui::ViewProviderCoordinateSystem, PartGui::ViewProviderAttachExtension
+{
+    PROPERTY_HEADER_WITH_EXTENSIONS(PartGui::ViewProviderLCS);
+
+public:
+    ViewProviderLCS();
+    ~ViewProviderLCS() override = default;
+
+    bool doubleClicked() override;
+};
+
+} // namespace PartGui
+
+
+#endif // PARTGUI_ViewProviderDatum_H

src/Mod/Part/Gui/WorkbenchManipulator.cpp

@@ -37,6 +37,7 @@ void WorkbenchManipulator::modifyMenuBar([[maybe_unused]] Gui::MenuItem* menuBar
 void WorkbenchManipulator::modifyToolBars(Gui::ToolBarItem* toolBar)
 {
     addSelectionFilter(toolBar);
+    addDatums(toolBar);
 }
 
 void WorkbenchManipulator::modifyDockWindows([[maybe_unused]] Gui::DockWindowItems* dockWindow)
@@ -71,3 +72,18 @@ void WorkbenchManipulator::addSelectionFilter(Gui::ToolBarItem* toolBar)
         }
     }
 }
+
+void WorkbenchManipulator::addDatums(Gui::ToolBarItem* toolBar)
+{
+    if (auto view = toolBar->findItem("Structure")) {
+        auto add = new Gui::ToolBarItem(); // NOLINT
+        add->setCommand("Part_Datums");
+        auto item = view->findItem("Std_Group");
+        if (item) {
+            view->insertItem(item, add);
+        }
+        else {
+            view->appendItem(add);
+        }
+    }
+}

src/Mod/Part/Gui/WorkbenchManipulator.h

@@ -54,6 +54,7 @@ protected:
 private:
     static void addSectionCut(Gui::MenuItem* menuBar);
     static void addSelectionFilter(Gui::ToolBarItem* toolBar);
+    static void addDatums(Gui::ToolBarItem* toolBar);
 };
 
 } // namespace PartGui

src/Mod/PartDesign/App/Body.cpp

@@ -219,7 +219,9 @@ bool Body::isAllowed(const App::DocumentObject *obj)
             //obj->isDerivedFrom<Part::FeaturePython>() // trouble with this line on Windows!? Linker fails to find getClassTypeId() of the Part::FeaturePython...
             //obj->isDerivedFrom<Part::Feature>()
             // allow VarSets for parameterization
-            obj->isDerivedFrom<App::VarSet>()
+            obj->isDerivedFrom<App::VarSet>() ||
+            obj->isDerivedFrom<App::DatumElement>() ||
+            obj->isDerivedFrom<App::LocalCoordinateSystem>()
             );
 }
 

src/Mod/PartDesign/App/FeatureSketchBased.cpp

@@ -1357,9 +1357,10 @@ void ProfileBased::getAxis(const App::DocumentObject * pcReferenceAxis, const st
     }
 
     if (pcReferenceAxis->isDerivedFrom<App::Line>()) {
-        const App::Line* line = static_cast<const App::Line*>(pcReferenceAxis);
-        base = Base::Vector3d(0, 0, 0);
-        line->Placement.getValue().multVec(Base::Vector3d(1, 0, 0), dir);
+        auto* line = static_cast<const App::Line*>(pcReferenceAxis);
+        Base::Placement plc = line->Placement.getValue();
+        base = plc.getPosition();
+        plc.getRotation().multVec(Base::Vector3d(0, 0, 1), dir);
 
         verifyAxisFunc(checkAxis, sketchplane, gp_Dir(dir.x, dir.y, dir.z));
         return;

src/Mod/PartDesign/App/ShapeBinder.cpp

@@ -28,6 +28,7 @@
 # include <BRep_Builder.hxx>
 # include <BRepBuilderAPI_MakeEdge.hxx>
 # include <BRepBuilderAPI_MakeFace.hxx>
+# include <BRepBuilderAPI_MakeVertex.hxx>
 #endif
 
 #include <unordered_map>
@@ -194,6 +195,10 @@ void ShapeBinder::getFilteredReferences(const App::PropertyLinkSubList* prop,
                 obj = plane;
                 break;
             }
+            if (auto point = dynamic_cast<App::Point*>(it)) {
+                obj = point;
+                break;
+            }
         }
     }
 }
@@ -244,6 +249,13 @@ Part::TopoShape ShapeBinder::buildShapeFromReferences(App::GeoFeature* obj, std:
         shape.setPlacement(obj->Placement.getValue());
         return shape;
     }
+    else if (obj->isDerivedFrom<App::Point>()) {
+        gp_Pnt point;
+        BRepBuilderAPI_MakeVertex mkPoint(point);
+        Part::TopoShape shape(mkPoint.Shape());
+        shape.setPlacement(obj->Placement.getValue());
+        return shape;
+    }
 
     return TopoDS_Shape();
 }

src/Mod/PartDesign/Gui/ReferenceSelection.cpp

@@ -148,12 +148,12 @@ bool ReferenceSelection::allowOrigin(PartDesign::Body *body, App::OriginGroupExt
     if (fits) { // check that it actually belongs to the chosen body or part
         try { // here are some throwers
             if (body) {
-                if (body->getOrigin ()->hasObject (pObj) ) {
+                if (body->hasObject(pObj, true) ) {
                     return true;
                 }
             }
             else if (originGroup ) {
-                if (originGroup->getOrigin()->hasObject(pObj)) {
+                if (originGroup->hasObject(pObj, true)) {
                     return true;
                 }
             }

src/Mod/PartDesign/Gui/ViewProviderBody.cpp

@@ -342,11 +342,11 @@ bool ViewProviderBody::canDropObjects() const
 {
     // if the BaseFeature property is marked as hidden or read-only then
     // it's not allowed to modify it.
-    PartDesign::Body* body = getObject<PartDesign::Body>();
-    if (body->BaseFeature.testStatus(App::Property::Status::Hidden))
-        return false;
-    if (body->BaseFeature.testStatus(App::Property::Status::ReadOnly))
+    auto* body = getObject<PartDesign::Body>();
+    if (body->BaseFeature.testStatus(App::Property::Status::Hidden)
+        || body->BaseFeature.testStatus(App::Property::Status::ReadOnly)) {
         return false;
+    }
     return true;
 }
 
@@ -355,7 +355,15 @@ bool ViewProviderBody::canDropObject(App::DocumentObject* obj) const
     if (obj->isDerivedFrom<App::VarSet>()) {
         return true;
     }
-    if (!obj->isDerivedFrom(Part::Feature::getClassTypeId())) {
+    else if (obj->isDerivedFrom(App::DatumElement::getClassTypeId())) {
+        // accept only datums that are not part of a LCS.
+        auto* lcs = static_cast<App::DatumElement*>(obj)->getLCS();
+        return !lcs;
+    }
+    else if (obj->isDerivedFrom(App::LocalCoordinateSystem::getClassTypeId())) {
+        return !obj->isDerivedFrom(App::Origin::getClassTypeId());
+    }
+    else if (!obj->isDerivedFrom(Part::Feature::getClassTypeId())) {
         return false;
     }
     else if (PartDesign::Body::findBodyOf(obj)) {
@@ -375,8 +383,10 @@ bool ViewProviderBody::canDropObject(App::DocumentObject* obj) const
 
 void ViewProviderBody::dropObject(App::DocumentObject* obj)
 {
-    PartDesign::Body* body = getObject<PartDesign::Body>();
-    if (obj->isDerivedFrom<Part::Part2DObject>()) {
+    auto* body = getObject<PartDesign::Body>();
+    if (obj->isDerivedFrom<Part::Part2DObject>()
+        || obj->isDerivedFrom<App::DatumElement>()
+        || obj->isDerivedFrom<App::LocalCoordinateSystem>()) {
         body->addObject(obj);
     }
     else if (PartDesign::Body::isAllowed(obj) && PartDesignGui::isFeatureMovable(obj)) {

src/Mod/PartDesign/Gui/ViewProviderDatum.cpp

@@ -2,22 +2,21 @@
  *   Copyright (c) 2013 Jan Rheinlaender                                   *
  *                                   <jrheinlaender@users.sourceforge.net> *
  *                                                                         *
- *   This file is part of the FreeCAD CAx development system.              *
+ *   This file is part of FreeCAD.                                         *
  *                                                                         *
- *   This library is free software; you can redistribute it and/or         *
- *   modify it under the terms of the GNU Library General Public           *
- *   License as published by the Free Software Foundation; either          *
- *   version 2 of the License, or (at your option) any later version.      *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
  *                                                                         *
- *   This library  is distributed in the hope that it will be useful,      *
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
- *   GNU Library General Public License for more details.                  *
+ *   FreeCAD is distributed in the hope that it will be useful, but        *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   Lesser General Public License for more details.                       *
  *                                                                         *
- *   You should have received a copy of the GNU Library General Public     *
- *   License along with this library; see the file COPYING.LIB. If not,    *
- *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
- *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
  *                                                                         *
  ***************************************************************************/
 

src/Mod/PartDesign/Gui/ViewProviderDatum.h

@@ -2,22 +2,21 @@
  *   Copyright (c) 2013 Jan Rheinlaender                                   *
  *                                   <jrheinlaender@users.sourceforge.net> *
  *                                                                         *
- *   This file is part of the FreeCAD CAx development system.              *
+ *   This file is part of FreeCAD.                                         *
  *                                                                         *
- *   This library is free software; you can redistribute it and/or         *
- *   modify it under the terms of the GNU Library General Public           *
- *   License as published by the Free Software Foundation; either          *
- *   version 2 of the License, or (at your option) any later version.      *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
  *                                                                         *
- *   This library  is distributed in the hope that it will be useful,      *
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
- *   GNU Library General Public License for more details.                  *
+ *   FreeCAD is distributed in the hope that it will be useful, but        *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   Lesser General Public License for more details.                       *
  *                                                                         *
- *   You should have received a copy of the GNU Library General Public     *
- *   License along with this library; see the file COPYING.LIB. If not,    *
- *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
- *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
  *                                                                         *
  ***************************************************************************/
 

src/Mod/PartDesign/Gui/Workbench.cpp

@@ -380,14 +380,6 @@ Gui::MenuItem* Workbench::setupMenuBar() const
     root->insertItem(item, part);
     part->setCommand("&Part Design");
 
-    // datums
-    Gui::MenuItem* datums = new Gui::MenuItem;
-    datums->setCommand("Create a datum");
-
-    *datums << "PartDesign_Point"
-            << "PartDesign_Line"
-            << "PartDesign_Plane";
-
     // additives
     Gui::MenuItem* additives = new Gui::MenuItem;
     additives->setCommand("Create an additive feature");
@@ -429,8 +421,6 @@ Gui::MenuItem* Workbench::setupMenuBar() const
 
     *part << "PartDesign_Body"
           << "Separator"
-          << datums
-          << "PartDesign_CoordinateSystem"
           << "PartDesign_ShapeBinder"
           << "PartDesign_SubShapeBinder"
           << "PartDesign_Clone"
@@ -490,8 +480,7 @@ Gui::ToolBarItem* Workbench::setupToolBars() const
           << "Sketcher_ValidateSketch"
           << "Part_CheckGeometry"
           << "PartDesign_SubShapeBinder"
-          << "PartDesign_Clone"
-          << "PartDesign_CompDatums";
+          << "PartDesign_Clone";
 
     part = new Gui::ToolBarItem(root);
     part->setCommand("Part Design Modeling");

src/Mod/Test/Document.py

@@ -338,17 +338,17 @@ class DocumentBasicCases(unittest.TestCase):
 
         res = obj.getSubObject("X_Axis", retType=2)
         self.assertEqual(
-            res[1].multVec(FreeCAD.Vector(1, 0, 0)).getAngle(FreeCAD.Vector(1, 0, 0)), 0.0
+            res[1].multVec(FreeCAD.Vector(0, 0, 1)).getAngle(FreeCAD.Vector(1, 0, 0)), 0.0
         )
 
         res = obj.getSubObject("Y_Axis", retType=2)
         self.assertEqual(
-            res[1].multVec(FreeCAD.Vector(1, 0, 0)).getAngle(FreeCAD.Vector(0, 1, 0)), 0.0
+            res[1].multVec(FreeCAD.Vector(0, 0, 1)).getAngle(FreeCAD.Vector(0, 1, 0)), 0.0
         )
 
         res = obj.getSubObject("Z_Axis", retType=2)
         self.assertEqual(
-            res[1].multVec(FreeCAD.Vector(1, 0, 0)).getAngle(FreeCAD.Vector(0, 0, 1)), 0.0
+            res[1].multVec(FreeCAD.Vector(0, 0, 1)).getAngle(FreeCAD.Vector(0, 0, 1)), 0.0
         )
 
         res = obj.getSubObject("XY_Plane", retType=2)