Fallback mesh support for Skeletalmesh components

Development Rendering
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Hi, we have been exploring Nanite on SkeletalMeshes in our project, but we noticed that unlike Nanite Staticmeshes, there is no current implementation to force a particular SkeletalMeshComponent to use a Nanite fallback mesh. It looks like bDisallowNanite for example is a flag that only exists on UStaticMeshComponent.

As we sometimes use the same skeletalmesh with translucent materials assigned (for example for building ghosts or scanning effects), it would generally simplify our setups a lot of we could lean in to forcing fallback meshes in these situations. We rather not go down the route of having a duplicate non-nanite version for each nanite skeletalmesh for example.

Are there any plans to bring the concept of nanite fallback meshes to Skeletalmeshes, or is there potentially already a CL available on more recent builds that we can tap into?

Thank you for looking into this!

Kind regards,

Mark Verkerk

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Steps to Reproduce

  • Add a SkeletalMeshComponent
  • Observe that there is no setting related to forcing a fallback mesh, or to disallow nanite, like there is on StaticMeshComponent’s
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Hi there, yes, you are right in that we have not quite fleshed out the logic for fallback meshes for Nanite SKMs. However, we recently started merging the code into UE5-Main, which was used to animate Nanite SKMs in our Witcher 4 demo for Unreal Fest Orlando. The code can be found in CL 44046683. A part of that code contains logic to begin generating fallback meshes (see SkeletalMeshBuilder.cpp); however, this code still needs some more work to be fully production-ready. If you are interested in using it today, you can do so, but I want you to know that this is still a bit unstable. We are aiming to have this fully working in a future release. Please let me know if you have any further questions.