rigging with blend shapes
 

I wonder if anyone can help me. I am new to Maya and experiencing some problems when attching a blend shape surface to my character rig.

I have a character all rigged up and Iam now creating the blend shapes for some facial animations but everytime I move the blend shape slider to animate the character surface moves back to the position it was in when duplicated.

I then decided to dettach all surfaces, create the blend shapes and then skin the character to the rig. This solved the moving back problem but just created other problems though - now when I rotate the joints the surface stretches and deforms out of shape.

Is there a general rule of thumb when using blend shapes with a character rig?

Please help????

I usally rig and get all the defromations/weights looking right before making the blends... The trouble you seem to be having sounds like you might have deleted history or freezed transformations on the blendshaped targets. Which would cause the shapes to move back to a certian target. Post a pic up if you still having troubles.. I'll have a look.

thanks kurt - i just did a wee test there and got it working by duplicating the head in world space and then deleting the target surfaces once the blend shapes were applied - seems to work fine, fingers crossed

i had read in the maya char rig book that the targets may cause problems if not deleted when animating

thanks for the response anyways

You probably need to change the deformation order.

Well my solution only worked with one animation and iam back at square one. Will try the deformation order (from the input list) to see if that works. Incidently I hadn't deleted the history nor froze tranformations on the blend shaped target surface - i will get a pic posted up asap to see if that helps anyone define the problem.

Hi rallan,

a screen grab would be nice... :)

regarding blendshapes, I would suggest to stay away from the parallel thingie if posible... since it sometimes seems to have unwanted sideeffects...

I would suggest you to either use the "default" or "front in chain" nodes... the "front in chain" should also be able to be thrown on the skinned mesh after it has been skinned, without needing to change the deformation order, since it should put itself in front of the other deformations as e.g. the skincluster...

however a good idea is to put a blendshapenode on the mesh before it get's skinned, then you are sure that it comes before the Skincluster (ofcause this depends on which node you chose)... but you can assign a empty blendshape node to it, without adding the shapes to it... this can then be done e.g. after the skinning... :)

also check the skinning, since it influences the vertices, e.g. the face look good in "neutral"/start position, but when you then activate the blendshape you change the positions, and then the vertices will e.g. not looked as they were supposed to if the weigthing isn't correct... :)

regards

Strarup

Looks like it was the deformation order that was causing all of the problems. I had initially tried to move it before the skin cluster in the input lists but that didn't solve it since I hadn't deleted my contruction history on the original model first of all. Once this was done the deformations worked fine on the rig.

Thanks for the response though.

:)