Advanced Skeleton 5 (Simplified Face Setup) - Skin Weighting Issue

Hi all,

Wondering if anyone has run into this issue or has suggestions on a fix?

I used the simplified face setup conversion from an advanced skeleton 5 auto rig in Maya. The skeleton mesh came in fine, but the animation test shows some issues with skin weighting.

I tested the fbx file in maya, and it does not display this skin issue, so something is happening ue4 end.

there is a limit to how many bones can influence a single vertex. Thats 8. A face is likely to exceed such limit. So you need to make extra sure that isn’t the case prior to import of the base mesh.

On top of that you have floating point precision. The mesh does not take weight values below .001 into account.
You’d have to modify and build a custom engine to allow for that if that is the issue.

I’m not sure that such an easy fix as changing a variable value and building is avaliable for the bone influence max number.

Those are about the only 2 issues that deal with mesh weight.

Then you have the fact that you may be importing a non triangulated mesh. It shouldn’t really change or affect weight, but it could potentially get some things to not display correctly if there is some hidden geometry within the skin or some similar anomaly.
its always a safe bet to triangulate within the DCC and import a perfect file that looks how you want it instead of how the engine decides triangulation should occur.

Thanks for the feedback Most_Host LA! Out of everything you mentioned, I did realize the problem area having much more than 8 influences per vertice. I’ve had a difficult time trying to fix these issues in Maya as I can set the limit of influences which break the skin in horrifying ways as well as prune the small influences. There’s just too many bones being generated in the simplified face rig that it makes the skin weighting a big task. I’m looking at alternatives as the whole point of using advanced skeleton 5 is to reduce the time spent on character rigging. I think there may be a way to unlock more than 8 bone influences per vertice, so looking into that now.

I’m not currently aware of any good pre-baked solutions, but the usual pathway to less work is to appropriate someone else’s weight paint.

Usually you do this off free solutions and just transfer the weight paint to your model. As a starting base, since you always need to clean up.

In this case, I’m not familiar with the particular skeleton at all, but I would assume you can remove influences in that specific area except for the 4 to 5 bones surrounding it without much of any difference.

My lip bones (manually painted) are actually set with a max of 3 influences. Granted, manually painting the area decently took about 2 days.

Also, if it helps any, the lower lip seems to be involved pulling the vertex down when the jaw opens.
It may be enough to just remove all the lower lip/lower jaw/chin bones from that area above the commissure.

you could do this by painting new weights of 0 value on the current pose, for the specific bones

[USER=“3140864”]MostHost LA[/USER] Hello Sir, We are also facing the same issue. The mesh seems to be normal when we play the animation in maya, but when we are importing it to unreal and playing the animation the skin is getting streatched.
We have also tried your answer like triangulating it in may and getting it to unreal, but that also didn’t work.
It would be very great full if you can help us in solving the issue

You could always delete all the weightpaint for the jaw and place it only on 1 bone.
after all the teeth always move together.

Also, your skeleton settings could be not properly set. they should be set to animation for facial stuff to work properly.