View Full Version : KIARAN...The Making of Leon: HELP

02 February 2005, 01:27 AM
in the video, you show a model of the forearm bones (shaft of radius and shaft of
ulna) being twisted while rotating joints. I was thinking you parented the
bones to the geometry. I tried to do that, but the joints just rotate the
bones. (There's no twisting effect like you show on your video.) But your videos
never mention how this is done. Can you give me step by step how you
did that? Would it be possible to talk to you in the mric?

02 February 2005, 01:14 AM
He probably uses ulna and radius parallel to each other and a twist joint in between them that acts as the twisting mechanism. Its just a matter of parenting the joints correctly. If this is not the case it is one solution.

02 February 2005, 11:29 PM
actually I think they're just skinned to the forearm twist joints. Nothing fancy.

02 February 2005, 03:25 AM
actually I think they're just skinned to the forearm twist joints. Nothing fancy.

Yep :) It's really a fairly staightforward setup. No complex trickery.

There are three joints in total. Elbow, Forearm, Wrist.

1.) Create elbow and wrist joints first.
2.) Because all three joints must lie in a perfect line, we need some way of placing the forearm joint perfectly in line with the elbow and wrist. Otherwise, a forearm rotation will make the wrist wobble.
3.) Create a linear (1 degree) curve with two CV's. Snap the first to the elbow, second to the wrist. This will create a perfectly straight line between the elbow and the wrist.
4.) Hold down the 'c' key to curve snap a third (forearm) joint between the elbow and the wrist.
5.) Before you parent this joint into the heirarchy, you must align it exactly with the elbow. Orient constrain it to the elbow, then delete the constraint in the hypergraph. Now their local rotation axis' are aligned.
6.) Parent the new forearm joint between the elbow and the wrist. All twisting should be done from the forearm joint.
7.) You can setup a wrist controller that will twist from the forearm using an expression, SDK or an orient constraint with some axis left out.
8.)Just smooth bind the mesh to the joints as usual. Paint the weights to smoothly blend between all three joints.

Hope that helps :)

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