Hey all,
I’m rigging a character with a wide stance, and his knees pointed slightly outward. In order to properly place the joints in the legs, the joints have to go diagonally and rotate outward. However, when I try to align the joints, I get junk values in the rotate. If I use the move tool to place the joints it messes up the orientation. If I align the joints using the joint orient, this brings up another problem, that is - I do plan on putting an RP/IK handle from the hip to the ankle, and I would need the joint orient values to be zeroed out in order to be aligned along a plane. I was taught that the rotate and joint orient should have zero values. How do I go about placing these joints in the proper place?
:?:
Hey Danny,
Basically, what you’re asking here is a bit of a mathematical impossibility. To stop IK popping, it IS best to have zero-values in the other two axis - but sometimes that’s not possible. Your choices are to only rotate the top joint into position and use the translate of the aligning axis (the one pointing down the chain) to position the knee and ankle OR to put a little twist in the other joints to match the best joint position. In either one, you will have to make a compromise - rig stability or joint positioning. The third, I guess is to mess up your joint orientation - but I’d take predictable joint orientation over joint placement and ik popping - though that might just be my personal preference. Someone might correct me on this, but as far as I’m aware these are your only choices.
There probably is a way of solving the pole vector position problem with some vector maths or through exact orientation/positioning - but since I generally just avoid having those values in the first place I’ve not really looked into solving it properly. Here is a thread that will give you some more insight into the issue and maybe you can jump to a conclusion on what will help you the best through it: IK with pole vector problems. Maya - Rigging - Tech-Artists.Org
Hope this helps!
fix the mesh, it is faster to just softselect the mesh and move it in to a good alignment or lattice it than it is trying to fight with the rig, Models to be rigged 99% of the time shouldn’t have a built in pose to them, that is animators job.
Fix the mesh to fit the joints to keep the skeleton clean.
Hey all,
Thanx for the help and advice. I’m just starting to wrap my mind around rotations,joint orients, etc. I figured that there would have to be some compromise with this type of model. However, after messing around with this , I did find something of a solution- that is I took the leg heirarchy, and grouped it, moved the pivot to the hip joint, and rotated the leg into position. I then ungrouped it and took the junk rotation values and put it onto joint orient, and zeroed out the rotation values. I don’t know if this really makes a difference. The most important thing is that the hip, knee, and ankle are on the same plane. Thanx again.
the only joint that the orient value remain a single value is the knee, with out that pole vectors and clean animation curves become a probelm. The hip isn’t a big deal, but check your knee value, more than one orient value and you should fix it.
