View Full Version : I cant weight my Koalas shoulder&belly!

02 February 2003, 03:15 AM
Hi guys this is my second post...

but i would really like some help on my rig for this character.

I just finished storyboarding an idea of mine about this koala...and...well after finishing the model i am a little stumped.

I cant get the shoulder to deform right. I was hoping you guys could guide me on what methods i should use that would allow my character to move/climb/swing around. Should i research muscle systems? should i be using influence objects?

I am currently trying my best to fuddle through Maya SmoothSkinning weight painting...but i dont feel like my results are very spectacular.

So what do you think?

Any direction towards detailed tutorials would be helpful and much appreciated. Or certain Muscle systems PDF files..hint hint.


02 February 2003, 03:17 AM
here is another view

02 February 2003, 05:40 AM
hey I don<t think you would realy need a muscle system for your guy; Usualy muscle systems are used for realistic characters to simulate more the feeling of the skin streching than bending! So thats what the people at work say!

as for your koala, he<s very nice but would probably be hard to bind since he doesn<t have any seperation between his head and his shoulders!!!(in fact he has no shoulders) It would be VERY hard for him even in real life to be able to lift his arms above his head! anyway, its surely possible!

But, for the initial pose you should make his stance a little less stiff like the picture I included. the arms and shoulder should be a little more contracted!! Also you should check that your mesh is well built to encourage the bends you desire!!

anyway hope I helped you out and get back to me! Give me some news on your work 'cause it looks cool!


Oh! By the way Does anyone know of a good tutorial on muscle deformations?? I also would like to know!

02 February 2003, 05:41 AM

I forgot to mention that in the picture I included the top images are the old sytem and the bottom one the new one!!! Hence use the new pose, better...

02 February 2003, 11:37 PM
have you tried using hold bones or anything like that?

02 February 2003, 04:57 AM
Hold bones? I am not familiar with hold bones. At least not through my experience with maya.

Please explain.

02 February 2003, 02:01 PM
Well I use them in lightwave but I dont see why you could not use them in maya. They would be bones that are only there to keep the shape of your geometry. They could rotate on an exprssion to give the effect of mucles moving. Don't know if this explenation helps at all or not. Lets say if the arms are strait out and you have a small buldge where you want the sholder to be. Place a bone right there and parent it to your sholder or clavical bone or what ever you may have named it. This bone does not have to rotate it is just there to hold the geometry in place so you still have some dencity to your sholder. It has been a while since I rigged anything in maya so I am not sure exactly how to exicute this in there. But it is somehting you may want to try.


02 February 2003, 06:35 PM
sorry i posted this in another thread butt here it is again....

have you considered useing corrective blendshapes?... these are the most valuable tool i have seen in rigging any character for these reasoons....

1 they are not too complicated
2 they evaluate fairly quickly (depending on mesh density)
3 they allow you to get the EXACT shape that you want...

so the way that i go about makeing corrective shapes is this:
you have to start with a duplicate of your geomitry that is NOT deformed... so select the mesh and show all the inputs and turn all the deformer nodeStates to "has no effect" this sets your char gemoitry to an undeformed state...

Then duplicate the mesh..... unlock then channels for the dup and this is the starting point for your corrective shape rename it to correctiveShoulderMesh or something like that... , you can set the original mesh nodeState back to "normal"

now add the dup as a blendshape to the original.... *and turn the blendshape ON*

then deform your character using your shoulder joint for example.... but just rotate one joint at a time and only in one axis at a time (ie rotate shoulderY so arm is pointing forward)...

now you can move the points of the shoulder around on the duplicate (correctiveShoulderMesh) and watch the original character update as you move the points...
once you get the original to the shape you are looking for you just need to set up a setDrivenKey....
the duplicate blendshape mesh endsup looking very odd in most cases but this is ok.....

repeat as neccecary for all the joints axis (ie you could have up to 6 corrective blendshapes for each joint rotation... +X -X +Y -Y +Z -Z) but you don't always need that many...

Lastly in order to get them to all work together they must all be in the SAME blendShape node... so after you sculpt them all delete the blendshape nodes that have accumulated on your mesh. Then select all the corective meshes first and the original last and create a blend shape... they HAVE to be in the same blend shape node so they do not fight each other.....

last but not least you set up the setDrivenKey the joint Rotate axis is the driver and the blendShape node is the driven.... the tedius part is keying all the blendshapes on and off... So as the shoulder rotateY goes from 0 - 90 degrees the blendShape goes from 0 -1

well there is my $0.02
sorry if i confused anyone feel free to ask me if you don't understand....

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