Disabling SMRT in a scene that contains grooms breaks VSMs

Development Rendering
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1

Tweaking SMRT behavior in such a way that will have it off for grooms, either through r.Shadow.Virtual.SMRT.SamplesPerRayHair or r.Shadow.Virtual.SMRT.RayCountDirectional/r.Shadow.Virtual.SMRT.RayCountLocal, breaks the VSM behavior.

2

Steps to Reproduce

  1. Create a new level using the Open World template;
  2. Add a local light and a cube that will cast shadows from this local light;
  3. Add a groom asset into the scene;
  4. Set r.Shadow.Virtual.SMRT.SamplesPerRayHair to 0. Note how the whole scene is fully in shadow now. Reset r.Shadow.Virtual.SMRT.SamplesPerRayHair to 1;
  5. Set r.Shadow.Virtual.SMRT.RayCountDirectional to 0. Note how the directional light is fully shadowed now, the local still works. Reset r.Shadow.Virtual.SMRT.RayCountDirectional to original value;
  6. Set r.Shadow.Virtual.SMRT.RayCountLocal to 0. Note how the local light is fully shadowed now, the directional still works.
3

Hello there,

Thank you for the report and the reproduction steps, I think I see where this is going awry.

I’ll file a bug report and get back to you with a tracking link when one becomes available.

Best regards,

Chris

4

Hello Chris!

Thank you, looking forward to the tracking link :blush:

5

Please find the tracking link available at Unreal Engine Issues and Bug Tracker (UE\-290828\).

Further updates will be reflected there.

Best regards,

Chris

6

Thank you so much! I will track the issue using the link, we can close this thread :slightly_smiling_face:

7

No worries, will do. I’m glad I could help with this issue.

Best regards,

Chris