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KayosIII
12-22-2002, 11:51 PM
Hi I am rigging a hand (more as a learning exercise than anything else) Most of it is going quite well but I cant quite get the thumb to deform the mesh properly....

The problem is with the fleshy Mount of the thumb Here are two pictures showing the problem....

http://www.midcoast.com.au/~rgcoy/thumb1.png http://www.midcoast.com.au/~rgcoy/thumb2.png

The hand is setup with a basic IK skeliton -- the mesh is bound by selectiong a joint and selecting the vertices to be bound to that joint.

MDuffy
12-26-2002, 11:18 PM
It looks like you really just need to go in and paint the skin weights better. The vertices that are close to the hand are weighted too much towards the thumb. That's the simple fix.

For a more complex fix you'd need to set up a "muscle" between the thumb and the base of the hand. Messiah has the muscle expression you can apply to bones. In other software packages you fake it by for example creating a bone on the thumb and aim constraining it so that it always looks at a point on the hand. Then you use an expression/node to calculate the distance between the bone base and the target point, divide it by the distance between those points in the "rest" position, and then feed the result into the scale of your "muscle" bone along the axis that points at the hand. To get squash and stretch, you feed the inverse of that value into the other two scale axis.

Like I said, the first solution is simpler. (^_^)

Hope this helps,
Michael Duffy
mduffy@ionet.net

KayosIII
01-09-2003, 04:02 AM
Originally posted by MDuffy
It looks like you really just need to go in and paint the skin weights better. The vertices that are close to the hand are weighted too much towards the thumb. That's the simple fix. Looks like its time to learn how to paint weights in my chosen software package.... :)

For a more complex fix you'd need to set up a "muscle" between the thumb and the base of the hand. Messiah has the muscle expression you can apply to bones. In other software packages you fake it by for example creating a bone on the thumb and aim constraining it so that it always looks at a point on the hand. Then you use an expression/node to calculate the distance between the bone base and the target point, divide it by the distance between those points in the "rest" position, and then feed the result into the scale of your "muscle" bone along the axis that points at the hand. To get squash and stretch, you feed the inverse of that value into the other two scale axis.

Like I said, the first solution is simpler. (^_^)

Sounds Interesting I think some sort of pictorial Diagram would make things easier to understand... Anyways thanks for your help

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