View Full Version : Combining Corrective Blendshapes with Facial blendshapes ??

05 May 2007, 01:21 PM
Hi guys .. I am really struggling to make two sets of blendshapes to work together. ..

For Instance, I have one set of blendshapes for facial expressions called Facial.
I have another set of blendshapes for corrective blendshapes called Corrective . But when I initiate my corrective blendshape it cancels out my Facial blendshapes and I have tried all the options eg : Parallel, front of chain etc...

Ummm Help !! Please


05 May 2007, 06:27 PM
Hi Lionwolf,
I'm assuming your using maya. The way I do it is to actually paint out the areas the corrective blendshapes do not need to be. I right click on the mesh and then select paint>blendshapes and the respective blendshape you want to edit.
Also changing the inputs order might help.


05 May 2007, 02:03 PM
Umm yeah stupid of mee ..I am using Maya . But how do you make your blendshapes work together? How do you stop one blendshape cancelling out the other. It either cancels out or exagerates the blend ??

05 May 2007, 06:17 PM
Its all about additve, and not replacive. A corrective shape is applied ontop of two or more shapes that are combined. This corrective shape will look completely odd but transform back to correct the mesh.

A corrective shape is a differential shape using the formula:

corrective shape = intialMesh + ((sigma Targets[n,..]) - achieve target)

so you take away the vert position of the combined targets from the acheived target and add this back on the base mesh vert pos. This becomes your new corrective shape. The acheived target is the shape YOU WANT to have the mesh look like when you combine the targets.

Comet's PSD or pose space deformer does exactly this.

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05 May 2007, 06:17 PM
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