Whitewater h17.5 Not to emit bubbles

[eyadorabi]

Hello,

Using Houdini 17.5 to create boat wake with white water.

Using the white water solver I where I would like to emit foam and spray over the flip surface. However, I do not want the bubbles as I am under the impression this would reduce simulation time and memory consumption.

That said, I couldn't figure out a way to stop the solver from emitting bubbles! Anyone was able to deal with this or any documentation or thread that could help?

 

[loogas]

Hi,

I'm fighting with this new way of creating whitewater as we speak  I cannot get rid of floating foam particles (floating above the surface), but I can answer your quesion I think: you have to go the opposite way. Not 0 but for example 100 - it's the dying rate (Aging Rate) - you force the bubbles to die fast. I think they have to be emitted but you just kill them fast. This was mentioned in a masterclass about the new whitewater system - which is always a must-watch imho  Good luck!

My problem:

 

[Andrea]

On 7/28/2019 at 11:29 AM, eyadorabi said:

Hello,

Using Houdini 17.5 to create boat wake with white water.

Using the white water solver I where I would like to emit foam and spray over the flip surface. However, I do not want the bubbles as I am under the impression this would reduce simulation time and memory consumption.

That said, I couldn't figure out a way to stop the solver from emitting bubbles! Anyone was able to deal with this or any documentation or thread that could help?

 

In the new whitewater solver there isn't anymore a distinct separation between foam, bubbles and spray as it was before. Or better, there is, but is more a fluid transition. If you activate the option "Add State Attributes" on the white water solver you will see that you'll have some extra attributes called foam, spray and bubbles.

 

The states are defined "simply" by the depth of the particle in the surface SDF, which is generated by the fluid simulation. This depth is not random at all, it's a range that goes between two values. It's specified by the parameters called Foam Location and Depth Range (always in the whitewater solver).

A particle is going to be fully bubble if is at the depth of Foam Location - Depth Range, so at the minimum of the depth range or below.

A particles is going to be fully spray if is at least at the depth of Foam Location + Depth Range.

 

Said this, if you want to avoid to have bubbles in your simulation, you can do it in several ways. I think the cleanest solution would be to act to the whitewater source, so before the data gets to the whitewater solver.

The first option in the whitewater source is "Limit by Depth". You should increase the minimum value from the default of -1 to something closer to the zero.

 

 

2 hours ago, loogas said:

Hi,

I'm fighting with this new way of creating whitewater as we speak  I cannot get rid of floating foam particles (floating above the surface), but I can answer your quesion I think: you have to go the opposite way. Not 0 but for example 100 - it's the dying rate (Aging Rate) - you force the bubbles to die fast. I think they have to be emitted but you just kill them fast. This was mentioned in a masterclass about the new whitewater system - which is always a must-watch imho  Good luck!
 

 

Definitely look at your emission volume from the whitewater source and also try to give a look at your surface volume, if it has something strange there. The particles seem like they are floating on a surface, they are spawned there or moving on a specific direction?

If they spawn at this position is probably your emit volume, otherwise could be the surfaceSDF or the velocity volume if they get shot in the air for example. Hard to be more specific without see it.

[loogas]

On 30.07.2019 at 5:41 PM, Andrea said:

Definitely look at your emission volume from the whitewater source and also try to give a look at your surface volume, if it has something strange there. The particles seem like they are floating on a surface, they are spawned there or moving on a specific direction?

If they spawn at this position is probably your emit volume, otherwise could be the surfaceSDF or the velocity volume if they get shot in the air for example. Hard to be more specific without see it.

I battled with that stuff for some time - the reason was the Collision SOP field in Whitewater Solver! I had a SOP attached but didn't input SDF Name - when I put "collision" there it sees the collision geo properly. Houdini is full of those small things... I think it should default to a dafault name.

Also - the particles are still floating a bit but that's because of pscale. They have to be tiny I suppose to be almost on the surface. Unfortunately sometimes they manage to go below the water surface from frame to frame which looks like a glitch.

Shading is a problem now - in the Ocean shader there's no absorption as far as I can see- but in the manual it says there is! I don't want to use to volume interior - to much render time hit.