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Flamingburrit008

Problems spilling liquid

Hello,

 

I’m a fairly new to Houdini and even newer to flip fluids and am running into a major problems

 

I’m trying to simulate a glass spilling wine on the ground.  Unfortunatly, no matter what I do I can’t seem to make this look right. When the fluid hits the ground, the particles  just keeps moving and expanding out into the distance. I’ve tried adjusting the stick on collision parameters, but that makes the liquid stick inside the glass itself a little too much. I’ve been searching for awhile now, but I can’t seem to find a solution to this problem. How should I go about dealing with this?

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Hi Mike

 

Check the physics tab pane of your collision object in the Dop network. You can adjust the Friction parameter to prevent particles sliding

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Thank you for the reply! I tried raising the friction for my collision object, and that seemed to help a little bit. However, in order to get my liquid to stay put I had to raise the value pretty high, much higher than it would be in real life (a smooth wood floor). Additionally, I imagine that I'm going to run into problems If I ever want to have other objects interact with this floor. I suppose I could use separate collision geometry with high friction for all of my liquids to interact with, but it seems a bit more like a hack. Most of the tutorials I have watched seem to recommend keeping physics as realistic as possible (at least for beginners like me). I've also tried raising the friction on the liquid itself, but that ends up looking really really weird. I kind of feel like I'm going about this the wrong way. I did do a little bit of research on fluids in general, and am wondering if I should try adding some viscosity instead?

wine_test02.hipnc

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Hi I played a bit with your file.

Maybe not the cleanest solution but kinda works :)

I blurred vel field (quick viscosity effect) and added drag to particles that are near surface. I also changed some bits around file.

 

Juraj

wine_test03.hipnc

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Hi Mike,

In FLIP simulation, from my experience, it's kinda tricky to find the "right" scale.
By "right", I mean the settings that Houdini likes.
If you try to create a simple FLIP simulation from the shelftools,
for example "FLIP Fluid from" a sphere with the default size(diameter: 1m, in H14),
you may find it quite easy to find the "right" parameters for that simulation.

I think your scale in this scene may be too small, there would be at least two potential problems:

1.  It's difficult to find the proper settings. It would be more intuitive and smooth to work in a "normal" scale.

2.  The calculation may lose some precision due to the very small numbers.

I suggest you can enlarge your scene scale, as long as it's not too far from the reality (like form a cup to a pond :P).
You can always tune the simulation with the help of ohter dynamic operators(like popdrag, popwrangle) or parameters on flipsolver, for instance "Timescale", to make it look right.
I tried scaling your scene 4 times bigger, and I found it much easier to control.
Hope that helps.
 

Edited by sohey

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Use control field on "stick on collision" parameter. Value in this field will be multiplier for "stick scale". And increase "max distance" a little bit. I get nice result with max value about 20 in control field.

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