What I am trying to accomplish here is absurdly simple. In a skeleton rig I have an extra bone for the deltoid, elbow, and wrist. Instead of using weight painting to achieve joints that behave, I am parenting the points in the joints to these extra bones, so that, for example, when I rotate the forearm, the elbow bone will rotate as well, but only half as much. This should be simple using constraints.
I have tried two different constraint setups. The first is to place an empty at the position of the joint, in the exact same position and orientation as the helper bone (the elbow). This empty is a child of the forearm so it rotates when the forearm rotates.
I then apply a Copy Rotation constraint to the elbow bone, with the empty as it’s target. By setting the influence of this constraint to 50%, you would THINK the elbow bone would rotate hald as much as the empty when the forearm is rotated.
Instead it simply does nothing EXCEPT when you turn the constraint influence from 0% to 100% the elbow bone moves a little.
I get essentially identical results when I place the empty at the tip of the elbow bone and use a track to constraint instead of copy rotation, as shown in the screenshot here.
I’ve tried everything to figure this out. I have gone so far as to make sure that all parent child relationships between ALL bones in the rig are removed, so the parent-child hierarchy is not somehow interfering with the proper operation of the constraints. I have turned IK and Skinnable off and on among other things.
What is most bizarre is that there have been brief moments when the constraint worked, then it would stop working again.
I’ve considered some kind of wacky gimbal lock problem, but can’t find anything to support this conclusion. The bottom line is, the constraints appear to simply not work. Can anyone offer ANY insight?
The file is at http://www.blendedplanet.com/rig.blend
Very very frustrating to have something so small cause so much trouble.
Dave
[/img]