View Full Version : Shoulder Deformations Please Help

05 May 2008, 12:35 AM
Hello all,
If everyone reading this thread could please take a few minuts to post your favorite / most reliable method of fixing shoulder deformations in Maya, I would greatly appreciate it.

I am currently working on a school production, that is being held up due to my lack of shoulder deformation skills. I have read many things about Comet's posedeformer, but it's an external plugin that would have to be installed into every machine that this scene is passed to. With students switching machines and taking scenes home all the time, an external plugin simply wont work. ( this is assumeing that the "posereader" is needed for the plugin to work once setup.) I wouldn't know if this is true due to not being able to install it with my non admin privliges here at school.

I have tried set driven keys driving small cluster fixes, but this is very rescricting for the multiple poses the character will be going through. Any tips or tricks you guys can share will be greatly valued.

Student TD.

p.s. I'd post examples of what im working with, but im under an NDA.

05 May 2008, 01:43 AM
I am not sure if I can really help, but I am curious to know if you are working on a realistic model or a cartoon model or hyper real creature? Have you tried multiple joints so that you can kind of simulate the muscle movements and deformations? Esp the pectoralis. Also the geometry itself will play a great role in making deformation look better. So you should make sure if geomtry is following antomy and it is deformable according to muscle structure.

05 May 2008, 03:27 AM
Guess i should have provided that info to start with eh? lol.. Not cartoony character, and not hyper real.. inbetween those two. as far as topology goes, the model is great. followed anatomy closely. Im not sure how phesable it is to add new bones in at this point in the production because animators have already been given the rig to animate on with a fast animation model. I just got onto this project and was not the one in charge of the initial rigging. I may try adding in more bones and have them driven by objects that are already on the rigged character, Thanks for the reply =).

Anyone else for ideas? i know this is one of the hardest places to get proper deformations due to the multiple axis' of the shoulder pivot. Just having a hell of a time figuring it out in Maya.

05 May 2008, 03:48 AM

I personally prefer the influence object or the corrective blendShape method for correcting the deformation on the mesh...blendShapes are always predictable so you can just create some corrective blendShape and do a quick and simple set driven keys to drive them....

05 May 2008, 04:58 AM
Corrective blendshapes may help you more since you can add them anytime esp since you already have some restrictions in what you can do now.

05 May 2008, 05:35 AM
You may want to look at this tutorial.

A big thing to remember about shoulders is to not put all the burden of shoulder movement on the deltoid muscle area. Once you raise your arm above about 90 degrees the clavicle joint that connects the upper arm to the spine should take over and spread the deformation throught a lot more of the upper body. Setting things up like this will avoid a lot of those kinking shoulder issues we all see way too much of, and saves a lot of headaches trying fix things through skin weighting.

05 May 2008, 06:09 AM
fahrenhiet digital has a great tutorial on shoulder defs.

05 May 2008, 07:57 AM
Kyleb you rock!. Thats exactly what I have been looking for. Simple, low calculation, good deformation, relatively simple setup, able to be fine tuned with simpel set driven keys, able to be setup at any point in the pipeline. and most of all.. dam good deformations for skinning alone. Thank you very much for the link =). Im gonna have to pick apart that script so i can learn to setup that up manuelly and not have to rely on a script makin all the magic happen.

I think it still needs some minor shape correction, only for the super extreme poses though. which brings me to my next question. How do you setup a corrective blendshape? I know how to create them, but the thing im struggling with is being able to see your deformed geomatry on the model your making the vert changes to. For example, say you want to fix the elbow with a corrective blendshape activated by the elbow's rotation. If you duplicate the objects mesh in the bindpose to setup a blendshape, how do you know what to correct if the model your making changes to isnt in that bent position? someone breifly mentioned the word "in between" to me while asking about this, so maybe that might spark some idea of what im talking about. I hope that examples clear enough.

Thanks again for all the quick replies.

Student TD

05 May 2008, 01:43 PM
For example, say you want to fix the elbow with a corrective blendshape activated by the elbow's rotation. If you duplicate the objects mesh in the bindpose to setup a blendshape, how do you know what to correct if the model your making changes to isnt in that bent position?
Student TD

Great script to model you corrective shapes in a pose.

Hope it helps.

05 May 2008, 04:35 PM
Thnks Aghill. I might try using this on my own projects, but for the production im working on, a third party plugin like this is pretty much banned due to pipeline issues. anybody know any simple mel or python scripts to do the trick?

(please correct me if im wrong in the fact that you'd need the plugin installed on every machine you passed the scene to during rendering / with other students using the same scene file on their home machines)

05 May 2008, 09:40 PM
Correction, that corrective blendshape tool worked out great. Its a one time use plugin where you dont have to have it installed on every computer running the scene, it just creates a link geomatry for you to create you blendshapes on. How freakin brilliant. Thanks again Aghill, this will work nicely =).

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