UE5.5 Mutable Skin BUG

zhangruizi · March 3, 2025, 2:55pm

I have found that with mutable-generated skeletal mesh, it will have strange deformations, such as vertex weights that have been incorrectly calculated

zhangruizi · March 3, 2025, 2:59pm

@GerardMTE Please check, thank you!

gustavorios2 · March 9, 2025, 4:51pm

I have the same issue.
it’s broken.
I just reported a bug, still waiting for a response

GerardMTE · March 10, 2025, 10:30am

Mutable currently does not automatically detect if a SKM has more than 8 bone influences per vertex. Probably what is happening here is that your SKM has 12 influences and those larger than 8 get remapped to other bones.

You can manually change this setting in Engine\Plugins\Mutable\Config\DefaultMutable.ini. Uncomment ;CustomizableObjectNumBoneInfluences=Eight and set it to Twelve.

gustavorios2 · March 10, 2025, 12:09pm

Oh my God… I searched for that setting within Unreal Engine but never thought to check the config files . I’ll take a look. Thanks!

zhangruizi · March 12, 2025, 10:55am

Did you solve it?

zhangruizi · March 12, 2025, 10:56am

Still the same, nothing seems to have changed

You can use the meta human head for testing, it must play an animation

zhangruizi · March 12, 2025, 10:57am

Did you solve it?

gustavorios2 · March 15, 2025, 5:00am

Sorry for the delay in responding. My issue was indeed the bone limit per vertex. The solution suggested by @GerardMTE completely fixed the problem.

ehgus5865 · March 18, 2025, 1:00pm

This doesn’t fix the issue either. When regenerated as mutable, the skeletal mesh skin values change. However, when using the same mesh in the mutable sample project, there are no issues.