vtkBandedPolyDataContourFilter can generate incorrect contours
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
If a polygon does not have a starting vertex where the contour values increase in both directions, incorrect clipping edges are generated. This can be demonstrated on a single triangle with point scalars of 0,0 & 1.
When searching to the right of the starting vertex for the first intersection point, ignore original vertices or intersections with the same scalar value.
vtkBandedPolyDataContourFilter.cxx, Revision: 1.42
At about line 626
Replace
if ( isContourValue[mR] ) intersectionPoint = 1;
By if ( isContourValue[mR] && s[mR] != s[idx] )
intersectionPoint = 1;