Forum: Carrara


Subject: IK Joints twisting very weirdly...

kelley opened this issue on Feb 07, 2003 ยท 3 posts


kelley posted Fri, 07 February 2003 at 10:35 PM

I just thrashed out a bunch of IK problems {pieces flying apart] and thought that I was ready to make a jointed character walk. [I did a test successfully]. So I built 'The Porter'. [see Carrara gallery] This SHOULD work. The Thighs (upper leg) and Shins(lower) work fine with IK applied and Custom>Limited Constraints.[on the X-axis] I can select the Thigh or Shin with the Selection Arrow, or the Rotate Arrow, and they'll move. The Ankle, or Sandal won't respond to either arrow. When I apply IK and Constraints to the bottom two [doesn't make any difference in which order] I can use the Selection Arrow to move the whole chain, but the bottom two are like inert weights. If I force the bottom two to move by moving the beads on the Limited/Custom circular slider, the Ankle, or Sandal rotate on the Y-axis. My previous problems [pieces flying apart] was due to having 'Physics' enabled. I very pointedly turned it off this time. Any ideas?

bluetone posted Sat, 08 February 2003 at 2:18 AM

I've had this same problem before, and allways spent a long time setting, then re-setting, my constraints. It allways seemed counter-intuative until I read a comment that twillis made recently about how she sets up her constraints, and the solution is in the modeling. Set up your character with the hands, feet, and everything else is straight down when you apply the constraint. Then the orientations for the constraints all work with x, y and z in the same orientation as the world x, y and z. This seems to solve the disconection with the world coordinates, and helps the constraints make more sense. Hope this helps, and twillis, chime in here if I've mis-understood your reasoning.


kelley posted Sat, 08 February 2003 at 2:09 PM

bluetone: Thanks. I'll give it a try. Actually, I already did, but I can't undo the previous IK constraints, so I'll have to rebuild the legs, Shouldn't take too long. I'll be back tonight or tomorrow morn.