CGTalk - Problem when incerting a joint into a parcially bound character.

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D-e-W

03-12-2008, 04:12 PM

Hey everyone!

SO I am weight painting my character.
And since it is my first time ever making a human or humanoid I am bumping into problem after problem.
But now I have problem for ya!
That is of cource if you have the time :)
No pressure

This time it is the knee. I have been cheking around and found out that the best way to make a good knee deformation is tou use two joints for the knee. right?
But unfrotunatley I have already bound and skinned parts of my character and am finnished with them so I cant unbind the character completley (or rather I would really like to avoid this).
So when I incert a joint in the knee and then move the skeleton, my other geometry (the one that is finnished and bound) gets screwed up (its the shoe of the character by the way).

So what i am trying to do is incert a joint into a parcially bound character.
Is this possible at all?
Or is there a way around it?
A fix for this problem would really help out.

Thanx!

martin

Boucha

03-13-2008, 06:13 AM

Hey, I suggest that you donot have to place a joint but rather you can just tweak your skin weights by painting it in such a way that the knee or elbow deforms correctltly, for eg. the knee bone is paint weighted in such a way that it is weighted to the knee completely, where as the thigh bone doesn't effect the knee area but is weighted to the surrounding of the knee...or else you could temporarily disable the skin weight of the mess and rebind after adding a bone....copy/paste....etc

twedzel

03-15-2008, 12:03 AM

One of the ways I add in joints is to unbind with the keep history option on, then reselect the bind joints, add in the joints you want ot add and just rebind (it'll keep the old weighting since the old skin node is never deleted). It's a little old school but it works reliably.

Oh I assume your only binding to specific joints under your bind options and you are using smooth bind. If you bind to the entire heirarchy then just make sure your new joints are in the heirarchy when you rebind.

If you bind to specific joints theres a simple little mel script can help with this process, Select the mesh a type

select -r `skinCluster -q -inf`;

It basically just selects the influences on the selected meshes skin cluster.

refract

03-17-2008, 07:27 AM

I usually just save a copy and redo it all. Its safer I have found than using any script. (rebind to the same original bones, and refrence in the old skinned version and use copy weights) Make sure to zero out joints beforehand.

nilslerin

03-18-2008, 09:38 PM

I don't see the problem. Just select a joint from the hier and go to bindpose. Then select the new joint, shift-select skinned geometry and go to skin-> edit smooth skin-> add influence. Make sure the settings for adding influence is set to lock weights at zero. This way the joint will be added and no weights are changed, then just add the weights desired for the new joint.

refract

03-19-2008, 04:53 AM

You can try it that way, but there is about a 50/50 chance of undesirable results. Adding a joint changes the prebind matrix, and the bindpose doesn't always accept it properly.

I'm using 8.5 btw.. perhaps its different in 08?

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