0025132: Visualization - treat any TopoDS_Solid as closed volume

Advanced mechanism implemented:
- BRep_Tool::IsClosed() method is used to detect non-manifold solids and open shells
- Non-manifold solids are split into closed and open shells

Adding message in test case

src/StdPrs/StdPrs_ShadedShape.cxx

@@ -257,7 +257,14 @@ namespace
       }
       case TopAbs_SOLID:
       {
-        theBuilder.Add (StdPrs_ToolShadedShape::IsClosed (theShape) ? theCompoundForClosed : theCompoundForOpened, theShape);
+        for (TopoDS_Iterator anIter (theShape); anIter.More(); anIter.Next())
+        {
+          const TopoDS_Shape& aSubShape   = anIter.Value();
+          const Standard_Boolean isClosed = aSubShape.ShapeType() == TopAbs_SHELL &&
+                                            BRep_Tool::IsClosed (aSubShape) &&
+                                            StdPrs_ToolShadedShape::IsTriangulated (aSubShape);
+          theBuilder.Add (isClosed ? theCompoundForClosed : theCompoundForOpened, aSubShape);
+        }
         return;
       }
       case TopAbs_SHELL:
@@ -483,12 +490,15 @@ void StdPrs_ShadedShape::Add (const Handle (Prs3d_Presentation)& thePrs,
   // add wireframe presentation for isolated edges and vertices
   wireframeFromShape (thePrs, theShape, theDrawer);
 
-  // IsClosed also verifies triangulation completeness - perform tessellation beforehand
+  // Triangulation completeness is important for "open-closed" analysis - perform tessellation beforehand
   Tessellate (theShape, theDrawer);
-  const Standard_Boolean isClosed = StdPrs_ToolShadedShape::IsClosed (theShape);
+
+  // The shape types listed below need advanced analysis as potentially containing
+  // both closed and open parts. Solids are also included, because they might
+  // contain non-manifold parts inside (internal open shells)
   if ((theShape.ShapeType() == TopAbs_COMPOUND
-    || theShape.ShapeType() == TopAbs_COMPSOLID)
-   && !isClosed
+    || theShape.ShapeType() == TopAbs_COMPSOLID
+    || theShape.ShapeType() == TopAbs_SOLID)
    &&  theToExploreSolids)
   {
     // collect two compounds: for opened and closed (solid) sub-shapes
@@ -515,7 +525,8 @@ void StdPrs_ShadedShape::Add (const Handle (Prs3d_Presentation)& thePrs,
   else
   {
     shadeFromShape (theShape, thePrs, theDrawer,
-                    theHasTexels, theUVOrigin, theUVRepeat, theUVScale, isClosed);
+                    theHasTexels, theUVOrigin, theUVRepeat, theUVScale,
+                    StdPrs_ToolShadedShape::IsClosed (theShape));
   }
 
   if (theDrawer->IsFaceBoundaryDraw())

src/StdPrs/StdPrs_ToolShadedShape.cxx

@@ -35,27 +35,23 @@
 #include <TopExp_Explorer.hxx>
 #include <TopoDS.hxx>
 
-namespace
+//=======================================================================
+//function : isTriangulated
+//purpose  :
+//=======================================================================
+Standard_Boolean StdPrs_ToolShadedShape::IsTriangulated (const TopoDS_Shape& theShape)
 {
-  //=======================================================================
-  //function : isTriangulated
-  //purpose  : Returns true if all faces within shape are triangulated.
-  //           Same as BRepTools::Triangulation() but without extra checks.
-  //=======================================================================
-  static Standard_Boolean isTriangulated (const TopoDS_Shape& theShape)
+  TopLoc_Location aLocDummy;
+  for (TopExp_Explorer aFaceIter (theShape, TopAbs_FACE); aFaceIter.More(); aFaceIter.Next())
   {
-    TopLoc_Location aLocDummy;
-    for (TopExp_Explorer aFaceIter (theShape, TopAbs_FACE); aFaceIter.More(); aFaceIter.Next())
+    const TopoDS_Face&                aFace = TopoDS::Face (aFaceIter.Current());
+    const Handle(Poly_Triangulation)& aTri  = BRep_Tool::Triangulation (aFace, aLocDummy);
+    if (aTri.IsNull())
     {
-      const TopoDS_Face&                aFace = TopoDS::Face (aFaceIter.Current());
-      const Handle(Poly_Triangulation)& aTri  = BRep_Tool::Triangulation (aFace, aLocDummy);
-      if (aTri.IsNull())
-      {
-        return Standard_False;
-      }
+      return Standard_False;
     }
-    return Standard_True;
   }
+  return Standard_True;
 }
 
 //=======================================================================
@@ -88,6 +84,12 @@ Standard_Boolean StdPrs_ToolShadedShape::IsClosed (const TopoDS_Shape& theShape)
     }
     case TopAbs_SOLID:
     {
+      // Check for non-manifold topology first of all:
+      // have to use BRep_Tool::IsClosed() because it checks the face connectivity
+      // inside the shape
+      if (!BRep_Tool::IsClosed (theShape))
+        return Standard_False;
+
       for (TopoDS_Iterator anIter (theShape); anIter.More(); anIter.Next())
       {
         const TopoDS_Shape& aShape = anIter.Value();
@@ -96,17 +98,12 @@ Standard_Boolean StdPrs_ToolShadedShape::IsClosed (const TopoDS_Shape& theShape)
           continue;
         }
 
-        if (aShape.ShapeType() == TopAbs_SHELL
-        && !aShape.Closed())
-        {
-          return Standard_False;
-        }
-        else if (aShape.ShapeType() == TopAbs_FACE)
+        if (aShape.ShapeType() == TopAbs_FACE)
         {
           // invalid solid
           return Standard_False;
         }
-        else if (!isTriangulated (aShape))
+        else if (!IsTriangulated (aShape))
         {
           // mesh contains holes
           return Standard_False;

src/StdPrs/StdPrs_ToolShadedShape.hxx

@@ -32,8 +32,12 @@ public:
 
   DEFINE_STANDARD_ALLOC
 
+  //! Similar to BRepTools::Triangulation() but without extra checks.
+  //! @return true if all faces within shape are triangulated.
+  Standard_EXPORT static Standard_Boolean IsTriangulated (const TopoDS_Shape& theShape);
+
   //! Checks back faces visibility for specified shape (to activate back-face culling). <br>
-  //! @return true if shape is closed Solid or compound of closed Solids. <br>
+  //! @return true if shape is closed manifold Solid or compound of such Solids. <br>
   Standard_EXPORT static Standard_Boolean IsClosed(const TopoDS_Shape& theShape);
   
   Standard_EXPORT static Handle_Poly_Triangulation Triangulation(const TopoDS_Face& aFace,

tests/bugs/vis/bug25132

@@ -0,0 +1,34 @@
+puts "============"
+puts "OCC25132"
+puts "============"
+puts ""
+####################################################################################
+# Visualization - Capping algorithm not working sometimes
+####################################################################################
+
+vinit View1
+vsetdispmode 1
+vclipplane create pln1
+vclipplane change pln1 equation 0 1 0 0
+vclipplane change pln1 capping on
+vclipplane set pln1 view Driver1/Viewer1/View1
+
+# Capping should be enabled for the solid with a bounding shell with Closed flag not set
+restore [locate_data_file OCC25132-flight_solid.brep] fs
+vdisplay fs
+vfit
+vdump $imagedir/${casename}_flight_solid.png
+vremove fs
+
+# Capping should be enabled for the solid with cavities
+restore [locate_data_file OCC25132-solid_with_cavities.brep] sc
+vdisplay sc
+vfit
+vdump $imagedir/${casename}_solid_with_cavities.png
+vremove sc
+
+# Capping should display a non-manifold solid with an internal open shell correctly
+restore [locate_data_file OCC25132-Partition_1.brep] p1
+vdisplay p1
+vfit
+vdump $imagedir/${casename}_Partition_1.png

tests/mesh/data/standard/P2

@@ -1 +1,8 @@
 set TheFileName shading_137.brep
+if { [string compare ${command} "shading"] == 0 && [string compare ${group} "standard"] == 0 } {
+   puts ""
+   puts "CR25132"
+   puts "san (developer) 2014-08-26 16:59"
+   puts "The shaded representation looks strange because it is treated as a closed solid by visualization (back faces of the triangles are not drawn)."
+   puts ""
+}