View Full Version : poseDeformer with shoulders

08 August 2005, 10:44 AM
does anybody have any special tips for using poseDeformer with shoudlers? i've been using this plugin extensivly for deformation and its much better than maya's blending, but on a high-res human character i'm still having problems with shoulders.

basically because its possible to get the arm pointing in the same direction with different values in the shoudlers XYZ, this means i could end up needing more than one fix for the exact same direction, if that makes sense. i know i can add a second poseDef node to do something a twist, but this could be problematic on a shoulder cause that twist might trigger at other angles when i don't want it to.

so far i'm up to 20 fixes on a single shoulder, and i can almost do a complete range of motion for when the arm is low, but i can tell i'll need up to 30 per shoulder, but then they can still be problomatic when they start to mix....

any tips on shoulders would be much apprec - (pref for high res characters).

08 August 2005, 02:21 PM
any tips on shoulders would be much apprec - (pref for high res characters).

In the past I've had great results already by just using influence objects on a properly setup clavicle - shoulder joint setup. You only have to deal with two rotations really in the shoulder joint as the twist rotation is handled by the bicep split joints anyways.
I'd be happy to hear any other tecniques/opinions though.

08 August 2005, 04:14 PM
I agree in part that twist should be split out--at least concepturally. However there are
poses where twist does effect the defromation upstream of the bicep. Still--imo--step
1 is to create a solid isolate bicep twist bind rig.

I don't know which pose deformer is being referred to here. I have had serious problems
with an inhouse pose deformer because it was simply interpolating between set poses.
When you got out of a pose range--it would artifact. It would also interpolate funkily
as it was simply averaging unweighted pose space data.

The micheal comet pose deformer has a cone weighting system and a no twist option. This
seems much more workable to me--but I haven't tried it. this is a good link

08 August 2005, 11:15 PM
hi guys thanks a lot for the replies:

Octagon: i've tried influence objects and they're really slow on my rig, as soon as skin components are enabled any high res rig will slow to less than 1 fps. not that i animate with that rig obviously but its nice to have about 5-10fps at least to check deformation. i would've thought there'd still be issues with influence oibjects as you still have to morph them into their new influence shape as the shoulder rotates, so there's the joint-driven blendshapes issue with the objects instead of the skin :)

i'm not quite sure what you mean by bicep split but would be interested to hear more about it.... so would that be like inserting another joint beneath the shoulder and using that for twists with SC-IK instead of the twist on the RP-IK..? hmmm animating with FK would be fun... :/ i dunno if i'll be able to re-bone my character at this stage :)

lucille: yep i'm using michael comet's poseDeformer - it works great for the most part and is an awesome tool, i'm still not sure about what the allow-twist option does, i couldn't find anything in the docs, but i'll keep at it.

08 August 2005, 03:41 AM
re comet pose space deformer with no twist--I believe in this mode it is just
computing the relative vector associated with the rotation--thus identical poses
generated with differing rotations would be considered as the same relative vector
and thus solved identically--Good luck


08 August 2005, 06:15 AM
re comet pose space deformer with no twist

ahhh thanks for that i'll try it out :) i havn't seen a 'no-twist' option, just an 'allow twist' attribute on the poseDeformer nodes... i assume that's the one...

08 August 2005, 11:14 AM
Yes that's the one, and I think it's set properly by default too. I'm far from a TD (real far) but I managed to get up and running with Comet's poseDeformer and made a real nice shoulder for my recent workshop, if I remember correctly just using all the default settings. I didn't test it extensively I just did 4 - 6 blendshapes and put an IK handle on the arm and pulled it around a bit, and it seemed to work great.

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