Hello people,

I am just starting out with Houdini. So, probably, very basic stuff here. I have used my Perception Neuron suit to do a variety of moves… exported them as a .FBX and imported the file into Houdini. I have used this mesh to be a fluid emitter into a FLIP container.
Quick Star-jump test [youtu.be]

The particles are, now, only emitting from the arms and head of the character.

Rendered Arms and head only emission [youtu.be]

I'm starting to understand the viscosity of the fluid, but I'm struggling with how it breaks apart. The thinner parts of he fluid break apart, which I expect, but then join up again on the next frame. Or, a huge hole will appear with one frame's difference. I'm presuming it is primarily to do with surface tension, but there are so many options and values to tweak, I don't know where to start.

Any help in narrowing it down or pointing me to a tutorial that looks at this would be a great help.

I am using Houdini 15.5.717

Thank you,

Neil

Play around with the Influence and Droplet Scale on the Surfacing tab of the Particle Fluid Surface node. I find the default influence of 3.0 to be too large, compared to the droplet scale. The droplet scale must always be lower than the influence scale. I try to keep them fairly close when surfacing.

Try 0.92 for Influence Scale and 0.72 for Droplet Scale. Sometimes I will increase the default Voxel Scale from 0.75 to 0.92 as well. By increasing the voxel scale you can make surfacing happen quicker. Lower voxel scale cause surfacing to take longer.

Basically find a nice frame that represents the problem in it's worst state then start tweaking the above mentioned scale values. At this point you should be working close to your final Particle Separation value. So dial in the fluid for resolution then tweak away at scales.

I have read that reseeding can contribute to “popping” so if you don't need it try a sim with it turned off. Also to keep the particle count constant you may want to experiment with turning off Kill Outside Volume Limits in the FlipSolver.

PS: you might as well upgrade to Houdini 16.

Enivob
PS: you might as well upgrade to Houdini 16.

I'll have a play with those values. Thanks for the info.

As for version 16… I'm learning it as part of my MASTERS course, at the moment, and don't want to start mixing revisions. I presume they're not backward-compatible and the interface looks like it's changed a bit, visually, at least. The Fluid Suck looks pretty cool, though, in H16.

Thanks again.

I've noticed in another thread that the FLIPsolver has a tab that relates to Enable Surface Tension, with a default range of 0-10. It does something, but I'm not sure of it's effect, how much influence it has and if 10 is ‘lots of tension’ & zero is ‘no tension’.