Multiple skin clusters

#1

Hey all,

I’m currently working on small piece of work that requires me to add additional levels of rigging detail in to a character. We would also like to maintain the low level rig so we are looking at multiple skin clusters on a rig. I’ve had a look at Sune Kempf site in which he explains how you could use preBindMatrix connections to help achieve this, but the blog posts area few years old and I’m wondering if anyone knows of something similar that has since been implemented into Maya.
Cheers
Will.

#2

are you talking about a setup where first skin cluster controls main deformation, then secondary one acts as a corrective?

This involves some work and can’t really be explained in one post, but the essence is in understanding how skinCluster calculates the deformation. For each joint, preBindMatrix and “current matrix” is maintained. Only the difference between those two is applied to mesh as a deform amount, so in general if you connect joint’s world matrix to both current and pre-bind, you’ll get no deformation at all.

Because maya won’t allow assigning another skin cluster to same mesh, you’ll have to use duplicate mesh to create second skin cluster. To bridge first skin to second one, connect outMesh of first skin to inMesh of source shape in deformation chain of second skin - use graph editor to find the root of deformation chain, shape should be named with “orig” suffix.

Now with that setup, you can, for example:

  • create a correctiveBaseJoint with a child correctiveOffsetJoint
  • constrain corectiveBase to first skin (any type of transform->geometry you prefer, e.g. rivet); it now moves with first skin
  • add correctiveOffsetJoint to second skin as influence;
  • connect correctiveBase as Offset’s pre-bind matrix. can’t remember here if you need inverse matrix or normal - experiment a little bit here needed:]
  • at this point, unless Offset moves relative to Base, second skin should not add any additional transformation.
#3

yep that s true . we use to set binding matrix to the inverseWorldMatrix when we want to reset the skinCluster, if you actually connect one to the other you will get no transformation while moving bones.
Anyway you can also pass the second skin cluster as a blendshape .But Anyway i dont think double skinCluster will let you do what you want, i mean be aware your gonna get double transform if the driver skeleton is the same .

I used that trick doule skincluster some times earlier in the days but the secondary skincluster was driven by joints that were not moving with the rig but connected on controllers that were moving with the main rig so if you were not moving directly the controll you were not moving bones of secondary skinCluster.
Or as correctly uiron said if you wanna use it as corrective that will require quite a bit of work

#4

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