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sekops
11-23-2007, 01:34 AM
Whats the best way for rigging thick geometry limbs without using PSD?

I have an idea for a quick alternative, qucik and easy route. With a standard 3 limb IKrp solver i create an extra joint in between the parent joint and the bottom-most child joint. What this extra joint does is, it stays in between the the joints.
Its a very bruttish way but it works for a midres type rig.

ANy other ideas?

arrow000
11-24-2007, 12:52 PM
I don't understand why you would need to do something fancy for thick limps. You might need some special setup for the deformations to work properly when you rotate, for example, the shoulder... Can you explain in more detail?

sekops
11-25-2007, 03:22 AM
I don't understand why you would need to do something fancy for thick limps

Skinning geometry on joints with thick girths generally gives unfavourable results. The joints would make the vertices furthest away from the joint intersecting with each other instead of bulging or shift its volume.

With the shoulder, that would be difficult, agreed. PSD or corrective blendshapes would be a solution, but that requires extra time to be worked on a middleground/midres rig in prod pipeline.

So a quick fix would be to have a floating joint in between, lets say in a leg setup, the thigh and ankle joint. So when the knee bends, the joint is always midway between those two joints but gets further away from the knee, thus bulging the geometry around the mid-section. Its rough, but requires little editing in the skinning.

So thats my method, was wondering if anyone used other alternatives?

refract
11-25-2007, 06:50 AM
Usually I just add an extra bone near the joint, and add a set driven key to it or an expression to ease unfavorable skinning. Shoulders, hips.. for twistbone stuff.
For knees and elbows, add an extra bone to keep the bulge.?/?
This is what I do, but I'm not sure if it answers your question. Thick girths on characters main problem I would see is intersections.

anthonymcgrath
11-28-2007, 02:52 PM
Usually I just add an extra bone near the joint, and add a set driven key to it or an expression to ease unfavorable skinning. Shoulders, hips.. for twistbone stuff.
For knees and elbows, add an extra bone to keep the bulge.?/?
This is what I do, but I'm not sure if it answers your question. Thick girths on characters main problem I would see is intersections.

agreed... clipping skin etc.. can be fixed with extra bones, influences and/or blendshapes (modify membership of verts!) lots of tools to sort that stuff out :)

double knee setups rock too! :D

sekops
11-30-2007, 12:11 AM
Yea, i just came up with a 'float' type joint that basically floats in between the two end joints, but using the vector product node, so its an easy setup

Set driven key is a good idea too. Cool

anthonymcgrath
11-30-2007, 08:18 AM
gotta admit you've lost me a bit there lol - any chance you could post up a screenshot or two - the node linkup and the end result? :)

sekops
12-02-2007, 02:28 AM
I think this method is a bit rudimentary. But it works. An additional thing is u need to put an orient constraint from the knee joint.

This is wat u do...
(i) Connect the world matrix to the matrix of the Vector Product.
(ii) Cange the operation of Vector Product to Point Matrix Vector
(iii) Average the vectors.
(iv) Connect it to the null.
(v) Constraint the floating joint to the null (point) and knee joint (orient).

http://i178.photobucket.com/albums/w271/jereme_photo/floating_joint01.jpg

http://i178.photobucket.com/albums/w271/jereme_photo/floating_joint02.jpg

Wat do u guys reckon?

refract
12-02-2007, 09:03 AM
Hmm.. ok.. I just did the same setup. Very nice. It appears Maya is using the same vector matrix product or point vector matrix product to produce the same results as the set driven key setup. Your setup is nice. But I'm looking at the hypershade and I'm getting different results.

Using set driven key's is an easy solution to this, (make sure your joint orients are correct) but if you mel your setup, it can work the same way?.. Someone correct me it i'm wrong here. thx

sekops
12-02-2007, 10:23 AM
Yes Set-Driven key and using expressions do the same result. But this allows the possibility of using MEL to automate this rigging process. Ive got a tonne of rigs to rig, and short of the manpower at work, this was meant to be a quick alternative.

Only downside is, its more limited than set-driven key but im sure using a sum node and a few conditions would give more options.

wat problems are u havin with this setup?

refract
12-03-2007, 01:40 AM
No problem with it, keep up the good work.

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