+ fix mesh trimming

src/Base/Tools2D.cpp

@@ -431,3 +431,19 @@ void Polygon2D::Intersect (const Polygon2D &rclPolygon, std::list<Polygon2D> &rc
     rclResultPolygonList.push_back(clResultPolygon);
 }
 
+bool Polygon2D::Intersect (const Vector2D &rclV, double eps) const
+{
+    if (_aclVct.size() < 2)
+        return false;
+
+    size_t numPts = GetCtVectors();
+    for (size_t i = 0; i < numPts; i++) {
+        Vector2D clPt0 = (*this)[i];
+        Vector2D clPt1 = (*this)[(i+1)%numPts];
+        Line2D clLine(clPt0, clPt1);
+        if (clLine.Intersect(rclV, eps))
+            return true;
+    }
+
+    return false;
+}

src/Base/Tools2D.h

@@ -154,7 +154,8 @@ public:
   // misc
   BoundBox2D CalcBoundBox (void) const;
   bool Contains (const Vector2D &rclV) const;
-  void  Intersect (const Polygon2D &rclPolygon, std::list<Polygon2D> &rclResultPolygonList) const;
+  void Intersect (const Polygon2D &rclPolygon, std::list<Polygon2D> &rclResultPolygonList) const;
+  bool Intersect (const Vector2D &rclV, double eps) const;
 
 private:
   std::vector<Vector2D> _aclVct;

src/Mod/Mesh/App/Core/Trim.cpp

@@ -346,18 +346,21 @@ bool MeshTrimming::CreateFacets(unsigned long ulFacetPos, int iSide, const std::
     // no intersection point found => triangle is only touched at a corner point
     if (raclPoints.size() == 0) {
         MeshFacet& facet = myMesh._aclFacetArray[ulFacetPos];
-        int iCtPts=0;
+        int iCtPtsIn=0;
+        int iCtPtsOn=0;
         Base::Vector3f clFacPnt;
         Base::Vector2D clProjPnt;
         for (int i=0; i<3; i++) {
             clFacPnt = (*myProj)(myMesh._aclPointArray[facet._aulPoints[i]]);
             clProjPnt = Base::Vector2D(clFacPnt.x, clFacPnt.y);
-            if (myPoly.Contains(clProjPnt) == myInner)
-                ++iCtPts;
+            if (myPoly.Intersect(clProjPnt, MESH_MIN_PT_DIST))
+                ++iCtPtsOn;
+            else if (myPoly.Contains(clProjPnt) == myInner)
+                ++iCtPtsIn;
         }
 
         // in this case we can use the original triangle
-        if (iCtPts < 3)
+        if (iCtPtsIn != (3 - iCtPtsOn))
             aclNewFacets.push_back(myMesh.GetFacet(ulFacetPos));
     }
     // one intersection point found => triangle is also touched at a corner point