How to fight rotating sim pieces?

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Hello,

I have many pieces produced by the voronoi fracture. When simmed some tiny pieces are rotating forever and as if they were rounded. I want to fix them so they settle down as the other pieces and also not to roll like a ball. Any ideas friends?
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Easiest way is to introduce some angular drag in a POP Wrangle by scaling the angular velocity attribute v@w. If you only want slower pieces to be dragged, you can always introduce a threshold so that the drag is only applied to slower-spinning pieces.

float spin = length(v@w);
if(spin < ch("threshold")) {
    v@w *= 0.9;
}
MOPs (Motion Operators for Houdini): http://www.motionoperators.com [www.motionoperators.com]
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If you are using the Bullet SOP, there is a world scale parm somewhere. This scales up your sim and all forces, sims it, and then scales it back down. This often fixes the “tiny pieces never stopping” syndrome.

If you are not using the Bullet SOP, you will have to roll your own… meaning scale the sim 10x or 100x, plus all forces appropriately and then scale back down after sim.
Sean Lewkiw
CG Supervisor
Machine FX - Cinesite MTL
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Thank you “toadstorm” and “mrCatfish” for the replies.
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