How to cast shadows from environmental lighting onto transparent shadow receiver?

Support
1

Hello!!!

I’m trying to render a scene that includes my model, a “ground plane” (planar mesh) and a Skybox. I want the lighting from the Skybox to cast shadows of the model onto the ground plane and I want the ground plane to be transparent so that the shaows appear to fall on the Skybox.

Currenly, I do this in Blender/Omniverse after exporting the VTK model as a gltf/.obj but it seems like VTK should be able to do all of this now?

I am using VTK 9.4 but I can move to 9.5 if that makes a difference.

I did see a post from @Sean_Curtis and @mwestphal from 2023 who was trying the same thing and ran into some issues - Have these issues have been fixed yet?

Can VTK currently do what I’m trying to achieve?

2

Yes, using ray tracing. I’d suggest to build VTK with OSPRay and experiment from there.

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3

Thanks Mathieu,

The approach the Sean was investigating was based on vtkShadowMap/ShadowMapBaker passes which didn’t require full on ray tracing. This was the approach I was hoping was now functional for casting shadows onto a transparent catcher illuminated by an enviroment .

Can you confirm that this apprach is not actually available and that I’ll need to go the ray tracing route instead?

4

It is still there: VTK: vtkShadowMapPass Class Reference

However, my understanding is that this class is not used much and may not work up to your expectations.