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FlipFluid Sim - Scene Scale Problem


Scratch

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Hey odforce,

 

Long time no see, but it's good to be back doing some houdini stuff again! :)

 

I need to simulate tiny (shower) water drops falling on the ground and while trying to set things up, I ran into a little scene scale issue.

 

Shower head nozzles are approx 2-5mm in diameter, emitting small jets of water or a series of small water drops which in my case, need to fall down on the ground from aprox 2m, creating small splashes.

 

Scene setup I tried so far:

Settings -> Hip File Options -> 1 Houdini Unit = 1mm (correct scene scale -> correct sim-results/behaviour)

Shower nozzles -> simple sphere as source object (for testing), diameter of 5 = 5mm. Moving it up 2000 units = 2m. So far so good, but that nozzle-spheres are now so tiny that the fluid source node settings for the source volume need to be crazy low, particle seperation levels for DOPs also...and even worse...i can't see stuff in the viewport because this thiny source is so small compared to the rest of my scene.

 

Next test I did was using 1m as Unit Size, and scaling down my source to 0.005m = 5mm. Same result, not working.

 

I am no expert for flip sims, maybe I did something wrong, but I don't think that my attempt is the propper way to go for such a sim (or is it?)...how would you guys say one should set up the scene for this type of sim?

 

Thanks for your help in advance folks! Looking forward to your answers!

 

Cheers from Munich!

Edited by Scratch
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Hi Phillip, try emitting from points. Sorry can not post a file. Just use shelf tool to emit particle fluid and make necessary changes in the nodes to emit from particles.  These  are the steps that I tried (hopefully i haven't forgot any of the steps, good enough to give you an idea )

Set the scene scale to 1 meter.

1. Take a circle(polygon) set the radius to to 0.05

2. Divide it to add sufficient points on it, then add "add" sop and choose delete geo but keep points option.

3. Create "particles" group out of these points using group sop (this group is used in dop source volume node / particles operation)

4. Add velocity to these points.

5. Create dopnet , fluid container and fluid object (particle separation to 0.005)

6. Source volume dop, set to source flip, set the path , pointing to source particles in sop.

(For surfacing , connect vdb from particles voxel size 0.0015, point radius scale 0.1 min radius 0.002 , then add convert vdb to polygon Isovalue 0.001 , change these values to get the desired look) Do not forget to transfer attributes from simulated geo to this surface.  

Hopefully this helps you.

Edited by sadhu
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