Hand elbow twist solutions

[jp_gillibert]

Hello,

I am wondering how a typical Maya user would setup the linkage between elbow and handpalm, ( I am a 3dsmax user), I cant seem to find a good solution and would be happy if someone could enlight me abit in this matter, the way I see it is that the palm rotation has to be all the way down to elbow, otherwise you get a nasty twist in the deformed mesh, so is there any wunderbar solution to this with say Maya, or any other package, would welcome any tip, weburl so that I can see if/how it's done in other packages, cheers

kare ola jacobsson

[pixxel]

One solution is to have an extra joint between the elbow and the wrist, and use that joint only for rotation around the axis described by the elbow-wrist line.

Pixxel

[blk]

yup pretty much an extra joint between the elbow and wrist
also what i do is if im using IK on the arm i draw the IK from the shoulder to the ulna joint (the one between the elbow and wrist) but then i take the end effector of that ik and point snap it to the wrist joint
so you can position and plant the arm from the hand/wrist

Bring it on

[pixxel]

I actually do the same thing, but I forgot to explain about the IK placement.

Thanks adding the explanation, John

In reply to:
yup pretty much an extra joint between the elbow and wrist
also what i do is if im using IK on the arm i draw the IK from the shoulder to the ulna joint (the one between the elbow and wrist) but then i take the end effector of that ik and point snap it to the wrist joint
so you can position and plant the arm from the hand/wrist Bring it on

Pixxel

[blk]

no need for thanks

Bring it on

[jp_gillibert]

Ok I think I get it, but how about the deformation of the mesh, does the above solution give a good deformation? I mean you have to consider that the influence of the rotational bone has to have a "falloff" so that it deforms more closer to palm and less closer to elbow, no? how is that done?

Regards
kare ola jacobsson

[blk]

well you have a couple options here
with a rigid bind you could apply a flexor lattice to the ulna bone
kind alike how chris landerith has it set up in the mastering the human character video from A|W
or if you smooth bind it you could go in and paint the weights of how much influence different joints have

Bring it on

[ibutter]

if you need a tutorial on this set up - go to
gnomon's free tutorials.

i find that you don't always get the best deformation with just a lattice here. you should attach in a couple of sculpt deformers(with set driven key) to simulate the muscle cluster movement around the elbow. (move your wrist you'll see it...) and if you want more.. blend shape the tendon on the wrist (bottom of the arm..palm side) and set driven to the rotation of that joint. (rotate you wrist and look under your palm.. you'll see the tendon pull). but that might be over kill depending on how close to the camera..and level of detail.. and all other factors.
hope that helps.

--| ibutter |--

[jp_gillibert]

Ok, thanks for the information, maybe I get myself a copy of that tape somewhere, cheers!

kare ola jacobsson

[torran]

What I just tried was to put in 3 joints between the elbow and the wrist, and it looked perfect because I can spread the deformation over the lower arm. To obtain the twist I just made a driven key, concerning the IK I just did what is described above..

Torran........................

[spudk]

I got a copy I'll sell for $20.
spudk@texas.net

In reply to:
Ok, thanks for the information, maybe I get myself a copy of that tape somewhere, cheers!

kare ola jacobsson