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Fenolis

Flip Fluids leaking through geometry

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Hi guys,

              I am trying to make a bowl filled with water. However, the fluids keep on leaking out from the collision geometry even though the collision geometry looks fine. Could anyone take a look at my hip and see what is wrong? :(

 

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Edited by Fenolis

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Haven't looked at the file, but in general with FLIP you have to consider that there's no such thing as "collision geometry".  All a FLIP sim sees is a collision volume - whether you convert a poly object to an SDF in SOPs, or connect it as a collision relationship in DOPs and let DOPs auto-convert it for you, you end up with a signed density field.  Basically, FLIP fluids will leak through anything thinner than around ~2-3 voxels thick, so unless you crank the resolution of your sim up massively, things like bowls, glasses, etc, will almost always cause leaking.  The simplest way is to create a proxy collision object, which maintains the same internal surface, where you intend the fluid to interract, but "fattens" the object outward on the side you're not interested in.  That way, you'll always ensure there's a resolvable volume behind the surface.

This is even more important if you're animating the collision object, as an animated thin object is going to skip straight through the fluid unless you use massive timestepping as well as massive resolution.

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That...blew my mind. Excellent explanation of the FLIP sim and a cool solution to boot. Thank you very much!

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