Vertices of quadratic cells (edes, quads ..) should not be merged before rendering
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
The vertices of the quadratic cells are always merged (in vtkUnstructuredGridGeometryFilter) before rendering, i.e., duplicates are removed. This is not the right behaviour. The merging should be turned off.
To test, use the following VTK legacy file description. A correct output should show the two edges in two constant colors and discontinuous at the joint vertex.
vtk DataFile Version 2.0
Test 1 : disjoints VTK_QUADRATIC_EDGE : one vertex in common ASCII DATASET UNSTRUCTURED_GRID POINTS 6 float 0 0 0 0.5 0 0 1 0 0 1 1 0 .5 0.5 0 0 0 0 CELLS 2 8 3 0 2 1 3 5 3 4 CELL_TYPES 2 21 21 POINT_DATA 6 SCALARS scalars float 1 LOOKUP_TABLE default 1.0 1.0 1.0 0.0 0.0 0.0