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Pancho

How to use grains for softbodies without the bouncing?

I spent hours today simulating some fruit falling into a glass with FEM. I took forever to calculate and I still ended with horrible penetrations of the glass.

I switched over to granular solids and it is soooo much faster, BUT the wiggling and jittering is an issue. A big one. it's like a rodeo which doesn't stop.

How do I take away the energy from the sim effectively without going for a diiferent look?

A goo like material should be as bouncy as a rocksolid one, and the other way round. Both should come to an abrupt stop with the first collision. Whatever is needed.

 

So, what's the secret?

Cheers

Tom

 

P.S.: Even values of 10.000.000 for both stiffness parameters don't prevent a heavy deformation on the first collision. Is it not possible to go a bit more into the rigid direction? The additional parameters are too time consuming. Not really possible to use them.

Edited by Pancho

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I went from 20 to 100 with the Constraint Iterations which is definitely enhancing the shape conservation, but I haven't figured out how to take the energy away from the grain. I let several layers of fruit fall into my glass. At one point they jump all out of it. Although they were all down at the bottom of the glass. But as soon as the last layers dropped onto the pile somehow all the inital energy gets added up and they jump together out of the glass. NOT - SO - GOOD.

 

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Since I need the sim for a still, the actual behaviour isn't so important than the end position. So I managed to "control" the jello with a drag node set to 0.85 for v and torque.

But this slows down the overall animation. Which attribute "inside" the grain node can I alter in a similar fashion, but without changing the amount of other forces. Is there a value which stores the kinectic energy and can be reduced with a drag node? Somehow a force remains inside the grains. Otherwise they couldn't jump out of the glass after they've been stable for a few frames. THere's something like a spring force which makes everything explode.

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