Bulging and cracking polystyrene

[scp]

Hi All

I was wondering if anyone could help. I'm trying to simulate an object bursting through polystyrene. First though I'm looking for the object to bulge and begin to crack the polystyrene and then finally for the polystyrene to collapse to the floor in pieces. I was beginning to get some results using cloth but how would I get the cloth to then fall apart as the object moves further through it?

Any help or other suggestions would be greatly appreciated.

Thanks

Simon

Edited April 18, 2008 by scp

[Marc]

Have you thought about using rigid bodies instead of cloth? And then applying the bulge as a cheat after the fact (magnet SOP or something)? Polystyrene/Styrofoam seems more rigid than clothlike.

[scp]

Thanks for the quick reply. I was experimenting with rbds as well but couldn't get the polystyrene to bulge as I wanted, but definitely it could be a good idea to use it in combination with sops. I'll give it a try.

[Jason]

Thanks for the quick reply. I was experimenting with rbds as well but couldn't get the polystyrene to bulge as I wanted, but definitely it could be a good idea to use it in combination with sops. I'll give it a try.

I would think you should take a rest pose of the geometry and pre-fracture it into primitive groups. Now bend the object any way you like, Magnets, Capture/Deform, WireDeform, Edit, ClothSolver on simple geometry which drives your fractured geo with a point lattice, whatever gives you the most control - until the break moment, and then do a staged handoff into RBD DOPs (RBD Fractured Object DOP). There is a Helpcard example to illustrate a way to handoff prim groups to DOPs.

[andrewlowell]

Wow, I could envision using three solvers for that one. First a cloth solver to bend, then a goemetry solver to fracture, then a RBD solver. Of course that might be severe overkill depending on what you want to do. Hand-animation of large pieces and deforming geometry with metaballs might work just as well

To use multiple solvers the switch solver comes to mind. There was a really good example of it's use on the gnomon RBD dvd, which involved switching from cloth to RBD.

[scp]

Thanks guys, off to the lab now for some testing.

[kleer001]

Just my 2 cents.

Technique aside, have you shot reference? Over the years of VFXing I've found that reference will help any effect look scads better if you have real life footage of what it's supposed to look like.