Nanite Skeletal Meshes Invalidate VSM

Development Rendering
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1

Sorry if this is a repeat question, but I was not able to find any docs or posts on this issue.

When using nanite skeletal meshes, I’m seeing them always invalidating the dynamic VSM cache even if they are not changing at all (no transform updates).

Is this feature just not working yet for nanite skeletal meshes? Or am I missing anything on getting them set up correctly?

Thanks!

-Jared

2

Steps to Reproduce

  1. Create a new level (Basic works well)
  2. Drop the Skeletal Mesh /Engine/Tutorial/SubEditors/TutorialAssets/Character/TutorialTPP into the level.
  3. Set the “Shadow Cache Invalidation Behavior” to “Rigid”
  4. Set the viewmode to VirtualShadowMap->CachedPage
  5. Note that there is no blue around the character meaning no dynamic VSM cache invalidation.
  6. Open TutorialTPP
  7. Convert it to nanite.
  8. Observe the shadow now turns blue.
3

Hello,

Thank you for reaching out.

I’ve been assigned this issue, and we will be looking into this VSM invalidation for you.

4

Hello,

Thank you for reporting this. I can confirm this issue can be reproduced as described in the latest CL, and have opened a bug report:

The tracker will be visible after it is approved internally at Epic Games and is publicly accessible.

If you have any further questions, please let us know.

5

Thanks for looking into this Stephen!

-Jared

6

Hey Stephen any updates regarding this?
The same could be said for the new Procedural Vegetation which uses Skeletal Mesh and invalidates Virtual Shadow Map even though wind is disabled

7

I’m facing the same issue, and the tracker says the fix is target for 6.0. So I guess we’ll have to wait 3 years for a fix.