Part: Fix orientation of internal shells of a solid (#26717)

* Part: Fix orientation of internal shells of a solid

If a solid consists of multiple shells then it can happen that the
internal shells have incorrect orientation that leads to a broken solid.

This fixes issue https://github.com/FreeCAD/FreeCAD/issues/24994

* Part: Add method Feature::fixSolids

This method explicitly checks for solids with the error
'BRepCheck_EnclosedRegion' that means that internal shells of a solid
are wrong.

Using ShapeFix_Solid fixes the solid.

---------

Co-authored-by: wwmayer <wmayer@freecad.org>

src/Mod/PartDesign/App/Feature.cpp

@@ -23,11 +23,15 @@
 
 #include <BRep_Tool.hxx>
 #include <BRepBuilderAPI_MakeFace.hxx>
+#include <BRepCheck_Solid.hxx>
+#include <BRepCheck_Status.hxx>
 #include <gp_Pln.hxx>
 #include <gp_Pnt.hxx>
+#include <ShapeFix_Solid.hxx>
 #include <Standard_Failure.hxx>
 #include <TopExp_Explorer.hxx>
 #include <TopoDS.hxx>
+#include <TopoDS_Builder.hxx>
 
 
 #include "App/Datums.h"
@@ -241,6 +245,44 @@ int Feature::countSolids(const TopoDS_Shape& shape, TopAbs_ShapeEnum type)
     return result;
 }
 
+TopoShape Feature::fixSolids(const TopoShape& solids)
+{
+    if (solids.isNull()) {
+        return solids;
+    }
+
+    std::vector<TopoDS_Solid> fixSolids;
+
+    TopExp_Explorer xp;
+    xp.Init(solids.getShape(), TopAbs_SOLID);
+    for (; xp.More(); xp.Next()) {
+        TopoDS_Solid solid = TopoDS::Solid(xp.Current());
+        BRepCheck_Solid bs(solid);
+        if (bs.IsStatusOnShape(solid)) {
+            const auto& listOfStatus = bs.StatusOnShape(solid);
+            if (listOfStatus.Contains(BRepCheck_EnclosedRegion)) {
+                fixSolids.emplace_back(solid);
+            }
+        }
+    }
+
+    if (fixSolids.empty()) {
+        return solids;
+    }
+
+    TopoDS_Compound comp;
+    TopoDS_Builder bb;
+    bb.MakeCompound(comp);
+    for (const TopoDS_Solid& it : fixSolids) {
+        ShapeFix_Solid fix(it);
+        fix.Perform();
+        bb.Add(comp, fix.Solid());
+    }
+
+    TopoShape fixShape(comp);
+    return fixShape;
+}
+
 bool Feature::isSingleSolidRuleSatisfied(const TopoDS_Shape& shape, TopAbs_ShapeEnum type)
 {
     if (singleSolidRuleMode() == Feature::SingleSolidRuleMode::Disabled) {

src/Mod/PartDesign/App/Feature.h

@@ -127,6 +127,11 @@ protected:
     TopoShape getSolid(const TopoShape&) const;
     static int countSolids(const TopoDS_Shape&, TopAbs_ShapeEnum type = TopAbs_SOLID);
 
+    /**
+     * Fix solids
+     */
+    TopoShape fixSolids(const TopoShape&);
+
     /**
      * Checks if the single-solid body rule is fulfilled.
      */