attributes versus weightmaps

[mattmos]

Hi all,

I'm experimenting with some basic ice stuff, using point position on the x axis to create a spread of values instead of painting a weightmap (so that I can use that attribute to drive a shape instead of modifying shape by weightmap).

I was wondering how expensive it is comparatively. Get point pos, vector to scalar, rescale, fcurve, set attribute, execute, then another branch to use that attribute to modify a shape.

Would it really slow down playback speeds of a rig? Would it get evaluated per frame, or just once? (assuming envelope comes after in the stack)

The benefits I guess are less cluster shapes stored in a model overall, ability to change the spread interactively, and reuse on any model without any laborious painting. However, speed of playback is still king in animation terms and if setting up too may attributes will slow a rig down to a crawl then its not worth setting it all up...

cheers

[Helli]

Not sure on this one.
ICE is quite intelligent when it comes to what has to be executed and what not.
But because you have a point position input I would say it is executed every frame and because of this I would say it is slower then using a weightmap for manipulating your shapes.

On the other hand it is easy to add a boolean switch to turn off the tree and expose this switch to the animator maybe as "optimize rig speed". You could turn off some other features with the same switch so at the end it might not make a big difference.

We used ice driven shapes all the time so I wouldn't worry too much about the speed.

[mattmos]

Helli, thanks for the reply, I've gone through and set up a character face rig and its all gone well.

The setup is a bit convoluted in some ways, considering the large amount of inputs (shape controllers etc), but its more stable than the shape manager and a lot lighter, also seems to have speeded up my rig speed from 30fps to 40fps. Didn't need to worry about rig playback speed then!

I should be able to set up a rig now by creating 30 odd shapes on a new face then importing the controllers, and then the ice compound and it creates all the links and splits up shapes into different areas automatically, sweet. Thanks ICE