From 3d0df45cd46f54bec8ec8fba64314838e5c955a8 Mon Sep 17 00:00:00 2001
From: PaddleStroke <pierrelouis.boyer@gmail.com>
Date: Tue, 10 Feb 2026 16:10:03 +0100
Subject: [PATCH] Assembly: BOM: take mirrored state of links in account.
 (#26113)

---
 src/Mod/Assembly/App/BomObject.cpp | 51 +++++++++++++++++++++++++++---
 src/Mod/Assembly/App/BomObject.h   |  6 +++-
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/src/Mod/Assembly/App/BomObject.cpp b/src/Mod/Assembly/App/BomObject.cpp
index 54fcb4b14f..b92eaedbc7 100644
--- a/src/Mod/Assembly/App/BomObject.cpp
+++ b/src/Mod/Assembly/App/BomObject.cpp
@@ -32,6 +32,7 @@
 #include <App/PropertyPythonObject.h>
 #include <App/Range.h>
 #include <Base/Console.h>
+#include <Base/Parameter.h>
 #include <Base/Placement.h>
 #include <Base/Rotation.h>
 #include <Base/Tools.h>
@@ -144,9 +145,15 @@ void BomObject::generateBOM()
     saveCustomColumnData();
     clearAll();
     obj_list.clear();
+    obj_mirrored_list.clear();
     size_t row = 0;
     size_t col = 0;
 
+    auto hGrp = App::GetApplication().GetParameterGroupByPath(
+        "User parameter:BaseApp/Preferences/Mod/Assembly"
+    );
+    mirroredSuffix = hGrp->GetASCII("BomMirroredSuffix", " (mirrored)");
+
     // Populate headers
     for (auto& columnName : columnsNames.getValues()) {
         setCell(App::CellAddress(row, col), columnName.c_str());
@@ -184,6 +191,9 @@ void BomObject::addObjectChildrenToBom(
         if (!child) {
             continue;
         }
+
+        bool isMirrored = isObjMirrored(child);
+
         if (auto* asmLink = freecad_cast<AssemblyLink*>(child)) {
             child = asmLink->getLinkedAssembly();
             if (!child) {
@@ -206,10 +216,14 @@ void BomObject::addObjectChildrenToBom(
             // Check if the object is not already in (case of links). And if so just increment.
             // Note: an object can be used in several parts. In which case we do no want to blindly
             // increment.
+            // We also check if the Mirror state matches. Mirrored parts should not group with
+            // non-mirrored parts.
             bool found = false;
             for (size_t i = siblingsInitialRow; i <= row; ++i) {
                 size_t idInList = i - 1;  // -1 for the header
-                if (idInList < obj_list.size() && child == obj_list[idInList]) {
+                if (idInList < obj_list.size() && child == obj_list[idInList]
+                    && idInList < obj_mirrored_list.size()
+                    && isMirrored == obj_mirrored_list[idInList]) {
 
                     int qty = std::stoi(getText(i, quantityColIndex)) + 1;
                     setCell(App::CellAddress(i, quantityColIndex), std::to_string(qty).c_str());
@@ -225,7 +239,7 @@ void BomObject::addObjectChildrenToBom(
         std::string sub_index = index + std::to_string(sub_i);
         ++sub_i;
 
-        addObjectToBom(child, row, sub_index);
+        addObjectToBom(child, row, sub_index, isMirrored);
         ++row;
 
         if ((child->isDerivedFrom<AssemblyObject>() && detailSubAssemblies.getValue())
@@ -236,7 +250,26 @@ void BomObject::addObjectChildrenToBom(
     }
 }
 
-void BomObject::addObjectToBom(App::DocumentObject* obj, size_t row, std::string index)
+bool BomObject::isObjMirrored(App::DocumentObject* obj)
+{
+    // Determine mirror state based on Scale properties.
+    // We multiply scales to handle nested mirroring (e.g., Mirrored LinkElement inside Mirrored
+    // LinkGroup = Normal).
+    double accumulatedScale = 1.0;
+    if (auto element = static_cast<App::LinkElement*>(obj)) {
+        accumulatedScale *= element->Scale.getValue();
+
+        if (auto group = element->getLinkGroup()) {
+            accumulatedScale *= group->Scale.getValue();
+        }
+    }
+    else if (auto link = static_cast<App::Link*>(obj)) {
+        accumulatedScale *= link->Scale.getValue();
+    }
+    return accumulatedScale < 0.0;
+}
+
+void BomObject::addObjectToBom(App::DocumentObject* obj, size_t row, std::string index, bool isMirrored)
 {
     obj_list.push_back(obj);
     size_t col = 0;
@@ -245,7 +278,17 @@ void BomObject::addObjectToBom(App::DocumentObject* obj, size_t row, std::string
             setCell(App::CellAddress(row, col), (std::string("'") + index).c_str());
         }
         else if (columnName == "Name") {
-            setCell(App::CellAddress(row, col), obj->Label.getValue());
+            std::string name = obj->Label.getValue();
+            // Distinctly label mirrored parts so they are identifiable in the BOM
+            if (isMirrored) {
+                if (auto* linkedObj = obj->getLinkedObject()) {
+                    // We add a suffix only if the label is the same.
+                    if (name == linkedObj->Label.getValue()) {
+                        name += mirroredSuffix;
+                    }
+                }
+            }
+            setCell(App::CellAddress(row, col), name.c_str());
         }
         else if (columnName == "File Name") {
             setCell(App::CellAddress(row, col), obj->getDocument()->getFileName());
diff --git a/src/Mod/Assembly/App/BomObject.h b/src/Mod/Assembly/App/BomObject.h
index 2ea18d81b7..3d18954898 100644
--- a/src/Mod/Assembly/App/BomObject.h
+++ b/src/Mod/Assembly/App/BomObject.h
@@ -76,9 +76,10 @@ public:
     App::DocumentObjectExecReturn* execute() override;
 
     void generateBOM();
-    void addObjectToBom(App::DocumentObject* obj, size_t row, std::string index);
+    void addObjectToBom(App::DocumentObject* obj, size_t row, std::string index, bool isMirrored = false);
     void addObjectChildrenToBom(std::vector<App::DocumentObject*> objs, size_t& row, std::string index);
     void saveCustomColumnData();
+    bool isObjMirrored(App::DocumentObject* obj);
 
     AssemblyObject* getAssembly() const;
 
@@ -93,9 +94,12 @@ public:
 
     std::vector<BomDataElement> dataElements;
     std::vector<App::DocumentObject*> obj_list;
+    std::vector<bool> obj_mirrored_list;
 
 private:
     std::string getBomPropertyValue(App::DocumentObject* obj, const std::string& baseName);
+
+    std::string mirroredSuffix;
 };