More Dynamic/Realistic Animation?

madmuffin

Hey everyone, I'm not an animator at all but circumstance has me doing a little bit of work in it and I was wondering a few things on how to make animations that go beyond what bones can do as far as I can tell. For example, expanding and contracting the torso for breathing, or having a balloon swell up in size. Another problem I encounter frequently with mechanical things is how do you make things that slide forwards and backwards, since bones will only rotate or bend? Are there any tutorials or resources out there for non-standard animation techniques, stuff beyond simply posing bipeds or bone systems?

Right now my current bane is a cat model that swells up like a balloon and then keeps animating. I haven't got a clue how to do it, I did a blowing up animation with morph targets between a large and small cat, but I have no idea how to integrate this together with a bone structure so that I can animate the cat before and after he becomes huge.

EDIT: http://www.mediafire.com/?r3tzmrnylfu Here is the test scene I did the poofing cat test in briefly. If anyone wants to toy around with it and experiment with how to turn this into a model a game could support that would be grand.

cryrid

Another problem I encounter frequently with mechanical things is how do you make things that slide forwards and backwards, since bones will only rotate or bend?

I suppose it might depend on the engine/exporter, but usually you're not limited to just weighting a model to bone chains. Here's the pistol from Half Life 2 for example:


Instead of using bones for deformers, it is weighted to a few curves. Translating the blue box moves the slide, rotating the yellow square box rotates the hammer.

madmuffin

Weighted to curves? What does that mean? And how do you animate those boxes if they don't export with the gun mesh?

cryrid

Instead of a bone's position and orientation having influence over certain verts, the curve's (boxes) position and orientation have influences over them.

The boxes do export along with the rest of the deformers. Basically the rig you see in your 3d application is not how the engine is going to see it after it gets exported. It's not going to see bones or their solvers, just their position/rotation. Same goes for other deformers that have influence over the mesh such as the curves. For instance, here's the Rig for the pistol (bones and curves), and what it ends up as once compiled.



No bones, just a bunch of data.

EmAr

In some engines like CryEngine 2 you don't even have to create the helpers in some cases:

http://doc.crymod.com/AssetCreation/ImportExportAnim.html

And for things like facial animation, morphs are used I believe.