Object Constraints: Same method and object, different result

Artistic Support Animation and Rigging
1

Hey guys.

I’m attempting to set up a rig for an armoured knight and am using a Copy Rotation constraint on joint armour to get its rotation to be a median between the surrounding bones. Like so:

http://i93.photobucket.com/albums/l43/Marshal_banana/constraintissue1.png
constraintissue1.png944×643 113 KB

The knee armour is parented to the Shin bone, and has a Copy Rotation constraint using the Thigh bone:

http://i93.photobucket.com/albums/l43/Marshal_banana/constraintissue2.png

It’s working perfectly. But then I go to do the same for the opposite side, which has the exact same setup, and it’s screwing up; the knee armour shrinks into the leg when the influence is anything but 1.

The only thing that should even have a remote possibility of causing this is that I duplicated the left side and mirrored the pieces to make the right (Broken) side. But why should that have any impact at all?

EDIT
Aye, it’s definitely caused by the mirroring, somehow. In fact, when I try mirroring the object by scaling it by -1, it doesn’t flip over, it just kinda ‘starts over’ on the part where it would usually cross over. Perhaps the axes weren’t mirrored either or something?

2

I think I would be looking at the scale of the mesh objects, making sure the scale is 1 for all values. Other than that, I don’t really have an idea what might be causing the problems. If you could post the .blend file, I’d take a look at it. As an alternative, you could use a bone, extruded forwards from the knee, make it a child of the thigh, with a copy rot constraint targeting the lower leg at 50% influence and parent the mesh to the new bone…

Randy