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Switch off shadow for transparent objects in VTK / Paraview renderings

I am looking for a way to prevent transparent objects from casting shadows when rendering with VTK (or Paraview) and OSPRay. As you can see in the screenshot on the right, this effect is very annoying.

Of course, it only occurs when a ground surface is present, as in the right image. In the left image this ground surface is not there, so these disturbing shadows do not appear. What looks good in principle. The only problem is that the shadows of the non-transparent object can't be projected either, which doesn't look very realistic. Therefore this method fails.

What I want to achieve is a mix of both example images:

  • non-transparent objects should cast shadows
  • transparent objects should not cast a shadow, especially not at the boundary surface between two objects (here in the example the bottom surface of the blocks at the ground surface).

As far as I can see, there is no way to deselect shadow casting of individual objects in VTK. Only the render scene as a whole can be controlled. I also tried with Paraview, hoping that this feature is available in the UI. But it does not work here either.

Who knows more? enter image description here

Solution

  • I don't know of a way to do this yet, as OSPRay does not yet expose this control. Free to file feature requests with the ParaView (gitlab.kitware.com/ParaView) and OSPRay (github.com/ospray/ospray) to help us keep it in our development plans.