From 973dda6f8843f608fb3d6688510af025f2ec874b Mon Sep 17 00:00:00 2001
From: blobfish <blobfish@gmx.com>
Date: Fri, 21 Aug 2015 13:17:09 -0400
Subject: [PATCH] Part: ModelRefine: adding basis surface to cylinder.

---
 src/Mod/Part/App/modelRefine.cpp | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/Mod/Part/App/modelRefine.cpp b/src/Mod/Part/App/modelRefine.cpp
index 7bcb0866b..05216d8ba 100644
--- a/src/Mod/Part/App/modelRefine.cpp
+++ b/src/Mod/Part/App/modelRefine.cpp
@@ -435,11 +435,28 @@ FaceTypedCylinder::FaceTypedCylinder() : FaceTypedBase(GeomAbs_Cylinder)
 {
 }
 
+static Handle(Geom_CylindricalSurface) getGeomCylinder(const TopoDS_Face &faceIn)
+{
+  Handle_Geom_CylindricalSurface cylinderSurfaceOut;
+  Handle_Geom_Surface surface = BRep_Tool::Surface(faceIn);
+  if (!surface.IsNull())
+  {
+    cylinderSurfaceOut = Handle(Geom_CylindricalSurface)::DownCast(surface);
+    if (cylinderSurfaceOut.IsNull())
+    {
+      Handle_Geom_RectangularTrimmedSurface trimmedSurface = Handle(Geom_RectangularTrimmedSurface)::DownCast(surface);
+      if (!trimmedSurface.IsNull())
+        cylinderSurfaceOut = Handle(Geom_CylindricalSurface)::DownCast(trimmedSurface->BasisSurface());
+    }
+  }
+
+  return cylinderSurfaceOut;
+}
+
 bool FaceTypedCylinder::isEqual(const TopoDS_Face &faceOne, const TopoDS_Face &faceTwo) const
 {
-    //check if these handles are valid?
-    Handle(Geom_CylindricalSurface) surfaceOne = Handle(Geom_CylindricalSurface)::DownCast(BRep_Tool::Surface(faceOne));
-    Handle(Geom_CylindricalSurface) surfaceTwo = Handle(Geom_CylindricalSurface)::DownCast(BRep_Tool::Surface(faceTwo));
+    Handle(Geom_CylindricalSurface) surfaceOne = getGeomCylinder(faceOne);
+    Handle(Geom_CylindricalSurface) surfaceTwo = getGeomCylinder(faceTwo);
     if (surfaceOne.IsNull() || surfaceTwo.IsNull())
         return false;//probably need an error
     gp_Cylinder cylinderOne = surfaceOne->Cylinder();
@@ -623,7 +640,9 @@ TopoDS_Face FaceTypedCylinder::buildFace(const FaceVectorType &faces) const
 
     // Find outer boundary wires that cut the cylinder into segments. This will be the case f we
     // have removed the seam edges of a complete (360 degrees) cylindrical face
-    Handle(Geom_CylindricalSurface) surface = Handle(Geom_CylindricalSurface)::DownCast(BRep_Tool::Surface(faces.at(0)));
+    Handle(Geom_CylindricalSurface) surface = getGeomCylinder(faces.at(0));
+    if (surface.IsNull())
+      return dummy;
     std::vector<TopoDS_Wire> innerWires, encirclingWires;
     std::vector<TopoDS_Wire>::iterator wireIt;    
     for (wireIt = allWires.begin(); wireIt != allWires.end(); ++wireIt) {