Union operation failed due to "Bad shape cells detected", but all cells are triangle-cells.

[zhan1589]

Hi,
Thank you for your work and your help.
I'm running into another issue while trying to combine two polydata with union operation. It failed with the error message "Bad shaped cells detected". The two polydata has been passed through vtkTriangleFilter and vtkCleanPolyData before boolean operation, and I have checked that all cells have exact three points. The normals are looking fine to me. I have attached the two polydata meshes in .vtk files.
Could you please share some wisdom on this issue?
Thanks!
meshes.zip

[zippy84]

It's the same problem that #43 has.

Btw. you don't need to triangulate it. The library works with polygonal meshes.