View Full Version : ik knees and elbows help

09-13-2003, 10:17 AM
i can ik a leg and arm really good although sometimes it can be difficult to animate because the knees and elbows go out of control....how can i some how animate the elbow....pleas help.


09-13-2003, 08:26 PM
that's a very tough question, it depends on your character rig and what you're trying to do. Look for tutorials on character rigging, try www.splinegod.com

09-14-2003, 11:38 PM
Hey, I am testing with this same problem.
If you check out Lightwaves interview with Lukasz Pazera;
his AutoCharacter Setup 4 has an idea i was using for knee and elbow joints.
If you set a bone pointing forward on the knee, parented to the thigh bone, and set thighs bank controller to IK. Next you create a small null in front of the knee a little, set the knee bones Goal Object to the knees null, strength to 1 or so (considerably smaller then strength of ankle) and this will keep the knee relatively close to the point, obviously putting the control back in your hands. (the same process can be used on elbows)
Still, I am only testing this out, may change slightly, but still very dependable system.
Id just like to thank Lukasz for his dedicated study in this area, and for giving back to the community! :D
Good luck SEMIRO!!

09-14-2003, 11:50 PM
One thing that's important is you want to put a pre-bend in the joint to be IK'd. You essentially have to tell Lightwave which way you want your IK to bend, this allows for more predictable behaviour. You can of course, also put rangle limits on the bones in the motion panel to prevent it from bending backwards.

With the exception of maybe the shoulder, don't allow IK to control the bank, heading, and pitch for a bone. This is sure to give you problems.

09-15-2003, 02:45 AM
I always IK the H and P of shoulders/hips, and keyframe the bank to control elbow position. Some people like to add an elbow IK goal so they can rest them on tables etc..