From e4a52991b66203188448fecb197a72b5b9827e0a Mon Sep 17 00:00:00 2001
From: Abdullah Tahiri <abdullah.tahiri.yo@gmail.com>
Date: Thu, 2 Nov 2017 19:52:26 +0100
Subject: [PATCH] Sketcher: Restore inter-body expression engine links in
 Carbon Copy

---
 src/Mod/Sketcher/App/SketchObject.cpp     |  5 +++--
 src/Mod/Sketcher/App/SketchObject.h       | 11 +++++++++++
 src/Mod/Sketcher/Gui/CommandCreateGeo.cpp |  3 ++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/Mod/Sketcher/App/SketchObject.cpp b/src/Mod/Sketcher/App/SketchObject.cpp
index f7757ca99b..e8abc3d5dd 100644
--- a/src/Mod/Sketcher/App/SketchObject.cpp
+++ b/src/Mod/Sketcher/App/SketchObject.cpp
@@ -99,6 +99,7 @@ SketchObject::SketchObject()
     ADD_PROPERTY_TYPE(Constraints,     (0)  ,"Sketch",(App::PropertyType)(App::Prop_None),"Sketch constraints");
     ADD_PROPERTY_TYPE(ExternalGeometry,(0,0),"Sketch",(App::PropertyType)(App::Prop_None),"Sketch external geometry");
 
+    allowOtherBody = true;
     allowUnaligned = true;
 
     for (std::vector<Part::Geometry *>::iterator it=ExternalGeo.begin(); it != ExternalGeo.end(); ++it)
@@ -2090,14 +2091,14 @@ bool SketchObject::isCarbonCopyAllowed(App::Document *pDoc, App::DocumentObject
     App::Part* part_obj = App::Part::getPartOfObject(pObj);
     if (part_this == part_obj){ //either in the same part, or in the root of document
         if (body_this != NULL) {
-            if (body_this != body_obj) {
+            if ((body_this != body_obj) && !this->allowOtherBody) {
                 if (rsn)
                     *rsn = rlOtherBody;
                 return false;
             }
         }
     } else {
-        // cross-part link. Disallow, should be done via shapebinders only
+        // cross-part relation. Disallow, should be done via shapebinders only
         if (rsn)
             *rsn = rlOtherPart;
         return false;
diff --git a/src/Mod/Sketcher/App/SketchObject.h b/src/Mod/Sketcher/App/SketchObject.h
index 99fd79ef44..4ceceff49c 100644
--- a/src/Mod/Sketcher/App/SketchObject.h
+++ b/src/Mod/Sketcher/App/SketchObject.h
@@ -305,6 +305,14 @@ public:
     /// gets the solved sketch as a reference
     inline Sketch &getSolvedSketch(void) {return solvedSketch;}
 
+    /// Flag to allow external geometry from other bodies than the one this sketch belongs to
+    bool isAllowedOtherBody() const {
+        return allowOtherBody;
+    }
+    void setAllowOtherBody(bool on) {
+        allowOtherBody = on;
+    }
+
     /// Flag to allow carbon copy from misaligned geometry
     bool isAllowedUnaligned() const {
         return allowUnaligned;
@@ -349,6 +357,9 @@ protected:
     std::vector<Part::Geometry *> supportedGeometry(const std::vector<Part::Geometry *> &geoList) const;
 
 private:
+    /// Flag to allow external geometry from other bodies than the one this sketch belongs to
+    bool allowOtherBody;
+
     /// Flag to allow carbon copy from misaligned geometry
     bool allowUnaligned;
 
diff --git a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
index 25af80fa76..e1df861c5d 100644
--- a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
+++ b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
@@ -6535,6 +6535,7 @@ namespace SketcherGui {
             Q_UNUSED(sSubName);
             
             Sketcher::SketchObject *sketch = static_cast<Sketcher::SketchObject*>(object);
+            sketch->setAllowOtherBody(QApplication::keyboardModifiers() == Qt::ControlModifier || QApplication::keyboardModifiers() == (Qt::ControlModifier | Qt::AltModifier));
             sketch->setAllowUnaligned(QApplication::keyboardModifiers() == (Qt::ControlModifier | Qt::AltModifier));
 
             this->notAllowedReason = "";
@@ -6550,7 +6551,7 @@ namespace SketcherGui {
                         this->notAllowedReason = QT_TR_NOOP("This object is in another document.");
                         break;
                     case Sketcher::SketchObject::rlOtherBody:
-                        this->notAllowedReason = QT_TR_NOOP("This object belongs to another body.");
+                        this->notAllowedReason = QT_TR_NOOP("This object belongs to another body. Hold Ctrl to allow crossreferences.");
                         break;
                     case Sketcher::SketchObject::rlOtherPart:
                         this->notAllowedReason = QT_TR_NOOP("This object belongs to another part.");