PDA

View Full Version : Cartoon Rigging...


ngrava
11-13-2004, 06:24 PM
I thought I'd start a little thread about rigging for cartoon characters. I'd love to hear your ideas, theories, fantasies about future techniques and technologies that would help us be more flexible while animating.

One of the things that excited me the most when I went to Siggraph this year was seeing the Disney booth. Inside there was a guy demoing the software they had made during Chicken Little. It was basically a bunch of custom scripts for Maya that handled things like squash and stretch, all kinds of local deformations that stay relative to blend shapes and a really cool flexible IK systems. It was really amazing what they where able to do with it.

I came away with the feeling that the current crop of standard 3D animation tools out there are actually quite limited when used with cartoon type characters. Think about this for a second, I know it sounds crazy but cartoon characters tend to go against ridged bone structures and predefined morphing. What we need are tools that are (as Elasta Girl says) "More Flexible". Not just for squashing and stretching but also for things like moving elbows, wrists and any other appendage to anywhere you need it to be while still being able to use IK and not breaking the rig.

I've had this dream about a skeletal IK system for years. It would be based on splines instead of bones. The IK system would actually be based on Particle physics sort of like a spring or rag doll system but the joints can be translated anywhere using a sort of soft selection type manipulation. The fall off simply defines how much the current point can pull the other joints around (up or down stream). I hope this makes sense.

Anyway, I'd love to hear any ideas you guys have on the subject.

-=GB=-

pooby
11-15-2004, 12:58 PM
if you use regular Bone IK skeleton setups you'll always be limited in what you can do regarding squash and stretch, as the character has to bend in certain places, regardless of the amount of stretch involved.
I've just used a new rig for the first time that enables curved limbs rather than a fixed Knee or elbow joint and has extreme squash and stretch. I have found so far that the most effective way of setting this up is using as few bones as possible on a low poly cage. this gives you a great amount of control over the shape of the body without nasty distortion.
Then I use the low poly cage to deform a high-detailed model, keeping all the squash and stretch that wouldn't have been possible had I applied it directly to the detailed model.

ngrava
11-15-2004, 03:02 PM
Yeah, that's a great point! I haven't really had a chance to try this out yet in Max7 but there's the new Skin wrap deformer that would work great for this. Maya also has the same thing. I've sort of always tried to work this way though. Most of my character use as little geometry as possible in order to make the deformations as smooth as possible. Especially when working with the face and morphs.

Something just occurred to me; The whole ZBrush animation workflow is basically this as well... (well, duh!) But what I just realized is exactly how much of the model should be built as a low poly cage and how much should be built as displacements... It's the exact same thing as building a low poly cage for loose cartoon style animation. I've never been successful with this because I've never really understood exact relationship before. [shuffling sound as he gets busy]

Check out this interview with Taron (http://pixologic.com/zbrush/interviews/baysal_interview.html) where he uses a lowpoly cage to animate but uses expressions to morph between displacement maps. I think this is one of those things that was confusing me the most. As you can see in the picture, the low poly cage is really loose and barely resembles the final model. Although Taron effortlessly wields this technique, the geometry is just way to low for a situation where you where not using the displacement morphs.

Hmmmm... I've got a lot to mess around with tonight. :D

-=GB=-

CGTalk Moderation
01-19-2006, 06:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.