I'm trying to rig an object (a sink, actually) to make it "speak"; using the overflow of the sink for the mouth :

enter image description here

I managed to rig a round mouth with bendy bones :

enter image description here

But I'm quite new to rigging, and I can't find the correct way to define the influence of the rig on the geometry.

The mouth should be capable of doing some mouth expressions; nothing really too advanced, but I would like to make it smile, whistle and yawn.

enter image description here

A bit like in Alice in Wonderland, but I don't need it to be as good as that.

enter image description here

Almost nothing else than the hole should move, but it would be nice to have a influence around it (eg. if it whistle, the rig would move a bit of the geometry around the "lips" forward.

I did tests with vertex groups, Weight Paint, but it never looks good.

I also had some attempts with booleans (mouth separated from the sink) but it didn't look good.

How would you handle this? Blend file.

  • $\begingroup$ maybe try the Spline IK constraint? 3rd solution I cite here: blender.stackexchange.com/questions/116124/… $\endgroup$
    – moonboots
    Nov 8, 2021 at 15:29
  • $\begingroup$ Have you tried assigning only the near vertices instead of basically all vertices as you did so far? Besides, what you should always do is to have a root bone. For all the bones that are not supposed to deform the mesh, disable their Deform option, and then if there is any vertices that you don't want to deform with a bone, you assign them to the root bone. That will avoid issues, especially if you ever export your model. It should look like this i.imgur.com/wReCidq.gif $\endgroup$
    – L0Lock
    Nov 8, 2021 at 16:59
  • $\begingroup$ Your mouth needs more geometry to deform around the lips. As already mentioned your control bones have the [X] Deform option enabled. That's causes shading & deformation issues. Here is a quick test with a few support bones around the mouth and moved the bones a bit inside the "face" (Y-axis). These bones have the same purpose as the root bone, basically, they limit the deformation influence. But there are still deformation issues: i.stack.imgur.com/XQcBs.gif $\endgroup$
    – Blunder
    Nov 8, 2021 at 19:09
  • $\begingroup$ I didn't knew the Deform option, thanks. I added some geometry. But how do you assign vertexes ? With automatic weights, then refining it manually ? $\endgroup$
    – gordie
    Nov 8, 2021 at 20:33
  • $\begingroup$ If you want to assign the vertices to the root bone as L0Lock did you need to use Weight Paint or select the verts in Edit mode and assign them to the vertex groups. I've just used Automatic Weights. The support bones did the trick. You can refine it manually. (But I'm bad with manual weight painting and try to avoid it.) $\endgroup$
    – Blunder
    Nov 10, 2021 at 2:19


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