(probably a general VTK error) non-convex quads are drawn incorrectly
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
ParaView draws non-convex, non self-intersecting quads incorrectly. It seems that the problem is the following: to draw a quad, it splits it into two triangles, but since the quad is non-convex there is only one correct way of doing it. It seems that ParaView (or VTK) sometimes makes the wrong decision.
From what I can tell, ParaView takes the quad (a, b, c, d) and makes triangles (a, b, c) and (a, c, d), without checking for convexity. Because the description of class vtkQuad does not mention convexity, this is a bug.