Patch based character animation.

#21

Click here for Martins Tech notes.

Maybe this clears things up?

#22

I think we are all in out of our depth here

nope. :smiley: I may or may not be right, but my feet are still firmly touching the bottom of the pool.

#23

I sent of a message to Ken Baer at Hash, and here is his response:

The answer is “No,” and maybe. Like Renderman bicubic surfaces, what finally gets sent to the renderer can do a ray/surface intersection using a triangle intersection routine, but those aren’t really polygons. One way you can tell is that if you make a single 4-sided patch with “peaked” corners, so that it looks like a rectangle, then decal that. If you pull one of the corners during an animation, the whole decal distorts, not just one side of the decal would if the
flat patch was composed of two triangles. Also, when CG guys talk
about polygons, they’re talking about vertex numbers, and edge lists, which A:M definitely does not have. And the u-v values of Hash patches don’t match polygons either. We used to be straight bicubic intersection, but for speed reasons, we now do this compromise solution.

It appears that David and I were wrong…sort of. The patches are subdivided but not technically into polygons. So the patches aren’t directly rendered as patches, there is subdivision of some sort going on.

I will now bow out of the discussion, because I am clearly NOT touching the bottom of the pool. :slight_smile:

#24

Hrmn now I’m confused. I’d always assumed that hash patches were bezier patches with a fancy brand name.

What is the actual difference between a hash patch and a bezier patch?

#25

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