Backface Culling with PBR

Hello,

Is there a way to disable backface culling with physically based rendering? It seems that whenever PBR is enabled within VTK, backfaces are culled regardless of the setting of SetBackfaceCulling.

Thanks!

I haven’t noticed this until now, but indeed backfaces are never appear when PBR is used. This is a major limitation, but hopefully it is easy to fix.

@akaszynski it would be useful to submit a bug report to the VTK issue tracker. Maybe you could also have a look at the PBR rendering code, maybe the fix is trivial.

Until it is fixed, a possible workaround is to duplicate the polydata, use vtkReverseSense (to flip the face direction of all polygons), and append the result to the original polydata.

I dont not see how this could be related. Did you try enabling backfaces with BackfaceCullingOn ?

Even though backface culling is off, backfaces do not appear if PBR is used. If we switch to flat/Phong/Gouraud shading and leave everything else the same then backfaces appear as they should.

Ok, an issue is needed indeed.

Added an issue to https://gitlab.kitware.com/vtk/vtk/-/issues/18684