Expression-driven wrinkles

(originally posted on Valentine’s 2006… nothing better than spending all day in front of the computer coming up with animation techniques)

Hello again, everybody.

I’ve been working a little more on my female character. The rigging is technically finished but I still have to add some little details to make the character behave in a more organic way.

A guy at the forums showed me a sample video from the book “Stop Staring”, I think, where you would see wrinkles appear on the character’s face when he/she performs an expression. The technique could be done with either bumps or displacements, but I decided to use bumps for faster rendering.

What I did was to combine all the different bump maps to a layeredTexture node in Maya, and then I connected that as a bump map to my character’s face material. The network can be seen on the next image.

(no image)

I then used Expressions to connect the bump maps Alpha output to the corresponding facial expression, so when the expression hits a value of 1, the Alpha value will also be 1. Combining the facial expressions will result on combined wrinkles onto the face. Click to watch the sample video.

Any downsides using bumps instead of displacements? As you know, displacements generate actual surface tessellation and deformation, while bumps don’t. This means that, though wrinkles will show when using bump maps, they won’t be seen on profile shots since bumps don’t deform the geometry.


~ by nemirc on April 14, 2009.

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