View Full Version : Pole Vector Constraint vs Twist attribute on ikRPsolver

10 October 2010, 04:35 AM
Hi everyone! I'm in the process of creating a ik arm rig in Maya and was wondering if the twist attribute on a ikRPsolver was the same as using a pole vector constraint? Could I get away with just keyframing the twist attribute? Sorry if this is a dumb question but I couldn't find a definite answer anywhere. Thanks in advance!

10 October 2010, 06:29 AM
I am not much of a rigger myself, Just know the basics, but as a character animator I would hate to animate the twist attribute. The reason for this is that with the pole vector you can place it somewhere and have it sit there for many friends while the arm is animated around it. Like for example throwing something, where the elbow follows a path then it kind of stops to whip the hand around it. with twist you would have to counter key and it would be a pain in the ass. At least that is how I feel, I am sure some people don't mind.

10 October 2010, 06:41 AM
as a rigger, i suggest you ask the animators their preferences on your rig, on my personal opinion, i would rather setup a pole vector rather than a twist attribute.

10 October 2010, 09:29 AM
Aside from preferences, the pole vector stabilizes an IK-handle. What I mean by that is the IK-handle calculates how the joints need to be rotated to go from the root to the tip of the chain. However, this leaves to may options open, as twisting along the axis gives all valid solutions. With the polevector you define in which direction the rotation plane will point (this leaves one solution). Twist is an offset to this plane and will ALWAYS be setup on top of a pole vector.

10 October 2010, 03:30 PM
Thanks everyone for the suggestions and everyone is right about the pole vector. I understand what you mean BasHe as I did a few tests with just using the twist attribute and it is a bit of a pain to have the elbow move as smooth as a pole vector constraint or no-flip for that matter. Thanks again!

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10 October 2010, 03:30 PM
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