0030281: Regression to 7.2.0: Modeling Algorithms - Wrong result of CUT operation

Boolean Operations - Force the face with internal edges to be treated by the BuilderFace algorithm. It is needed for the cases when internal edges of the face go from side to side and should really split the face.
Test case for the issue.

diff --git a/src/BOPAlgo/BOPAlgo_Builder_2.cxx b/src/BOPAlgo/BOPAlgo_Builder_2.cxx
index 1dfc9cd..210dab9 100644 (file)
--- a/src/BOPAlgo/BOPAlgo_Builder_2.cxx
+++ b/src/BOPAlgo/BOPAlgo_Builder_2.cxx
@@ -292,31 +292,52 @@ void BOPAlgo_Builder::BuildSplitFaces()
 
     if (!aNbPBIn && !aNbPBSc)
     {
+      // If there are any alone vertices to be put in the face,
+      // the new face has to be created even if the wires of the
+      // face have not been modified.
+
+      // It is also necessary to check if the face contains any internal edges,
+      // as such edges may split the face on parts and it is better
+      // to send the face be treated by the BuilderFace algorithm.
+      // In case of alone vertices the check for internals will be performed
+      // in the BuildDraftFace method.
+      Standard_Boolean hasInternals = Standard_False;
       if (!aNbAV)
       {
         // Check if any wires of the face have been modified.
-        // If not, there is no need to create the new face.
+        // If no modified and internal wires present in the face
+        // there is no need to create the new face.
+        Standard_Boolean hasModified = Standard_False;
+
         TopoDS_Iterator aItW(aF);
         for (; aItW.More(); aItW.Next())
         {
-          if (myImages.IsBound(aItW.Value()))
+          TopoDS_Iterator itE(aItW.Value());
+          hasInternals = (itE.More() && (itE.Value().Orientation() == TopAbs_INTERNAL));
+          if (hasInternals)
             break;
+
+          hasModified |= myImages.IsBound(aItW.Value());
         }
-        if (!aItW.More())
+
+        if (!hasInternals && !hasModified)
           continue;
       }
 
-      // No internal parts for the face, so just build the draft face
-      // and keep it to pass directly into result.
-      // If the original face has any internal edges or multi-connected vertices,
-      // the draft face will be null, as such sub-shapes may split the face on parts
-      // (as in the case "bugs modalg_5 bug25245_1").
-      // The BuilderFace algorithm will be called in this case.
-      TopoDS_Face aFD = BuildDraftFace(aF, myImages, myContext, myReport);
-      if (!aFD.IsNull())
+      if (!hasInternals)
       {
-        aFacesIm(aFacesIm.Add(i, TopTools_ListOfShape())).Append(aFD);
-        continue;
+        // No internal parts for the face, so just build the draft face
+        // and keep it to pass directly into result.
+        // If the original face has any internal edges or multi-connected vertices,
+        // the draft face will be null, as such sub-shapes may split the face on parts
+        // (as in the case "bugs modalg_5 bug25245_1").
+        // The BuilderFace algorithm will be called in this case.
+        TopoDS_Face aFD = BuildDraftFace(aF, myImages, myContext, myReport);
+        if (!aFD.IsNull())
+        {
+          aFacesIm(aFacesIm.Add(i, TopTools_ListOfShape())).Append(aFD);
+          continue;
+        }
       }
     }
 

diff --git a/tests/bugs/modalg_7/bug30281 b/tests/bugs/modalg_7/bug30281
new file mode 100644 (file)
index 0000000..ed060f8
--- /dev/null
+++ b/tests/bugs/modalg_7/bug30281
@@ -0,0 +1,42 @@
+puts "========"
+puts "0030281: Regression to 7.2.0: Modeling Algorithms - Wrong result of CUT operation"
+puts "========"
+puts ""
+
+restore [locate_data_file bug30281_shape.brep] s1
+restore [locate_data_file bug30281_tool.brep] s2
+
+bclearobjects
+bcleartools
+baddobjects s1
+baddtools s2
+bfillds
+
+bbop r0 0
+bbop r1 1
+bbop r2 2
+bbop r3 3
+bbop r4 4
+
+foreach r {r0 r1 r2 r3 r4} {
+  checkshape $r
+  if {![regexp "OK" [bopcheck $r]]} {
+    puts "Error: the result of BOP is self-interfering shape"
+  }
+}
+
+checknbshapes r0 -wire 112 -face 88 -shell 4 -solid 4
+checkprops r0 -s 590506 -v 7.584e+006
+
+checknbshapes r1 -wire 58 -face 46 -shell 1 -solid 1
+checkprops r1 -s  976583 -v 2.24e+007
+
+checknbshapes r2 -wire 94 -face 82 -shell 1 -solid 1
+checkprops r2 -s 1.00882e+006 -v 1.4816e+007
+
+checknbshapes r3 -shell 0 -solid 0
+checkprops r3 -s empty -v empty
+
+checkprops r4 -l 9614.01
+
+checkview -display r2 -2d -path ${imagedir}/${test_image}.png