RBD collisions for animated geometry?

[etudenc]

Hi everybody!

I am writing in hopes of getting some guidance on a project I'd like to take on - creating my own version of the rock monster from

.

For first steps, I imagine I'd create the main structure of the creature (like chest, arms, legs) out of separate boulders and rig that in Maya (careful that no geometry collides at the first frame). I'd animate him doing whatever, combine all the geo, then export as a bgeo cache. In Houdini, I'd put all the separate boulders into groups with the connectivity and partition SOPs and then do the sim so that the big pieces don't interpenetrate.

But unfortunately that's where I'm stuck. In the interest of keeping this post short, I've attached a Quicktime of what I'm after, though on a very simplified scale. In a nutshell I would like to take animated geometry (example A) and sim it in a DOPS network so that the objects collide rather than interpenetrate when they come in contact, then continue on their animated way (like what you see in example B ). I've seen Peter Quint's helpful tutorials on DOPs and keyframes but I don't think that's the same thing, since in his examples I don't believe there's any going back and forth between simmed -> animated -> simmed, especially on a piece by piece basis. I don't know, perhaps there's a way to set each piece Active when a collision is detected then Inactive when it's no longer colliding?

Have wondered whether somehow attaching the boulders through springs or constraints might work, but seems to me the simmed boulders wouldn't return to their animated orientation/position after a collision.

Any thoughts or suggestions would be very much appreciated!

collidingSpheres.mov

Edited August 18, 2012 by etudenc

[edward]

As far as I can recall, the "simmed -> animated -> simmed" was exactly what the goal of doing DOP keyframes were about.

[etudenc]

As far as I can recall, the "simmed -> animated -> simmed" was exactly what the goal of doing DOP keyframes were about.

In the third and fourth lessons of DOPSs/keyframes he goes from animated to simmed but not back. In the fractured geo/keyframed animation lesson it's from animated to simmed. I think the moving back and forth repeatedly between the keyframed data and RBD data on a piece-by-piece basis is key. I just read a little about the Blend solver so perhaps that's a route to explore.