Hey everyone,
I'm playing around with FEM for the first time and I'm having trouble mixing different dynamic elements together (file below). I believe I used the Organic Mass shelf tool for the face and made the arm an animated rigid body, but I'm struggling to get the rigid body glasses to smear and imprint into the face on impact. I've tried making the glasses an active rigid body, but they don't seem to collide properly with the face (they always get hit through the face geo). I have a lot of experience with nCloth, so I'm guessing this issue might be due to penetration when the simulation starts?
Also, as a bonus question: What are some best practices for creating a slow mo giggle effect like this reference [youtu.be]? I'm guessing that I have to edit a combination of sub steps, scale time, and FPS. I'm not quite sure though… thanks!
Slow Mo FEM Simulation with Rigid Bodies
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- borbs727
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- michiel
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For a slow motion jiggle effect like this I have the following suggestions:
Use the Integrator Type on the finite element solver to “ABE2”, which gives you much more jiggle at low Min Substeps.
Because the hand is animating quite fast and you want to do slow motion, I would increase your FPS from 24 to 240 in the global animation options.
Because the hand will stay in contact with the hand for quite a few frames, I'd say increase the Collision Passes on the solver to something significantly larger, say 16.
I see that you have soft constraints sprinkled over some points of the head: Avoid having constraints in the region or close to the region where the hand hits, because the collisions competing with the constraints won't give nice looking results. Instead, put some constraints on the back of the head, or some points of the inside of the head.
Finally, I'd change the animation of the hand so that it moves back from the head and doesn't keep passing through it.
About the glasses: I'd save that for later and focus on getting the head looking right first. But if you do get to the glasses, you probably want to change them to be an ordinary RBD Object, not a packed RBD Object. Packed RBD objects don't collide with FEM. In recent versions of Houdini 16, DOPs will display a warning about this. You may even choose to make the glasses themselves a stiff finite-element Solid Object, to get the best interaction.
Use the Integrator Type on the finite element solver to “ABE2”, which gives you much more jiggle at low Min Substeps.
Because the hand is animating quite fast and you want to do slow motion, I would increase your FPS from 24 to 240 in the global animation options.
Because the hand will stay in contact with the hand for quite a few frames, I'd say increase the Collision Passes on the solver to something significantly larger, say 16.
I see that you have soft constraints sprinkled over some points of the head: Avoid having constraints in the region or close to the region where the hand hits, because the collisions competing with the constraints won't give nice looking results. Instead, put some constraints on the back of the head, or some points of the inside of the head.
Finally, I'd change the animation of the hand so that it moves back from the head and doesn't keep passing through it.
About the glasses: I'd save that for later and focus on getting the head looking right first. But if you do get to the glasses, you probably want to change them to be an ordinary RBD Object, not a packed RBD Object. Packed RBD objects don't collide with FEM. In recent versions of Houdini 16, DOPs will display a warning about this. You may even choose to make the glasses themselves a stiff finite-element Solid Object, to get the best interaction.
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- borbs727
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