[vtkusers] vtkPolyData and replicated vertices in the PointSet list

[Ferdinando Rodriguez y Baena]

Dear users,

I have just realised that vtkPolyData stores triangle information in the point list by replicating vertices in the list according to the facets index order. I assume this enables fast rendering, which is good for display purposes. However, I also intended to use the PolyData object as a container for surface information that I need for registration. I was expecting to be able to retrieve both vertex and polygon information for my closest point search algorithm from the PolyData object ( i.e. GetPoints() and GetPolys() ), however it appears that the PointSet list has replicated vertices and that the facet indices no longer correspond to the correct vertices in the PointSet list. By inspecting the source code, I realised that during loading of a WaveFront object file (vtkOBJReader.cxx), the original vertex index information is lost.

Any idea on how I can retain that information without modifying the source code? Or am I simply doing something wrong? Any help would be much appreciated.

Thank you.

Ferdinando
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