View Full Version : Bone Face rig problem

05 May 2011, 04:54 AM
Hello all, I have a character that I've rigged but I ran into an issue when it came to the face rig. Normally I'd do a morph target face rig wired into a UI, but this time I thought I'd try a bone rig. I've set up a bone face rig before which followed the setup that PEN demonstrated in his CG Academy DVDs and as i recall it all worked fine. I more or less duplicated that process, but now when I rotate the neck, some of the point helpers linking the face bones into place seem to drag behind.

I'll try not to be confusing here...

each bone in the face has a stretchy setup using lookat constraints and point helpers, one at each connection. So for instance, the stretchy control at the corner of the mouth is parented into a point helper that is parented to another point helper that shares the same orientation. This point helper, at the top of the hierarchy, is directly linked into the head bone, but is sharing a position constraint between the head bone and a the jaw bone. This is so that when I rotate the jaw open, the corner of the mouth will always stay between the top and bottom lips, but by grabbing the child of this point helper I can still move the corner of the mouth independently, and because the parent is linked right into the head bone it should follow the head when he looks around. Now, this set up makes sense to me and I don't understand why it's not working. when I rotate the head around, the corner of his mouth seems to drag behind.

If anyone understands what I'm talking about and has some idea please help. I'm using Max 2011



05 May 2011, 09:10 AM
It sounds like the position constraint is causing your problem. When you rotate the head bone its position is not changing, only its orientation which your child point helper should still inherit. The point helper will still move slightly if the jaw bone's pivot is offset from the head pivot - because its position is changing as the head rotates.

I think you'll need 2 further point helpers to solve this. Align both to your current problematic helper then parent one to the head and one to the jaw. Now position constrain the original point between the two new helpers.

Hope it helps


05 May 2011, 02:46 PM
It sounds like a very elegant solution. I'll try it tonight, thank you.

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05 May 2011, 02:46 PM
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