Foam not working Properly

[josh_gruitt]

Hey guys,

I am trying to do a simulation with Foam and at some point the foam start to appears from nowhere or in a strange way like going on a side way like a line.
You can see on the images attached that in one of the Sim there is line of foam that start to appears and its going to the side. In another image the foam starts to appearing on the edge.
Any reason ? Please, if someone can help me it will be great. Thank you.

[georgi.zhekov]

Hey,

The foam particles are born based on the foam birth threshold. It controls how fast the liquid particles need to be moving in order to produce foam and if it is too low - foam particles would spawn all over the place.

You can increase the foam birth threshold and this should solve the issue, though the foam around the boat would be probably a lot less. What you can do instead is to use the option called Birth volume inside of the Foam settings. You can create a dummy non-renderable and non-solid geometry that covers the area in which you wish to create foam (a box for example) and use it as a birth volume - this way the foam particles will be born only inside of the dummy geometry volume. You can find more about the option here - https://docs.chaos.com/display/PHX4M...Foam-FoamBirth

[josh_gruitt]

Ok. Many Thanks, I will try.

[josh_gruitt]

It works better, however as you mention I don't have any foam on the front.
Apart form the idea of creating a dummy geometry volume....
Is there an easier solution ? Maybe increase or slow down the speed of the ship ?

[georgi.zhekov]

The foam birth threshold controls how fast the liquid needs to be moving in order to produce foam - so if your liquid is moving faster you will need higher threshold.
If you make the ship move faster you can get away with higher foam birth threshold.

Hope this helps!

[josh_gruitt]

Thanks Georgi I will try. One more thing I have this water on the front that should be smoother and less thicker. I read on the Help Doc that increasing the Meshsmooth on the Rendering tab it will help. .
However, it makes more smoother but the mesh water still looks thick on the front.
Please, let me know if you have another tip to improve the front water. Many Thanks

[Svetlin.Nikolov]

When you enable "Use Particles" in the mesh smoothing options, you can reduce the particle size and make the mesh thinner.

[josh_gruitt]

Yes I can see a very good improvement. I will render some frames. Many Thanks

[Svetlin.Nikolov]

Yay, glad it helped!

[josh_gruitt]

Thanks Svetlin

I think the simulation is working well. However, I have those cyan colour on the foam. I have changed the foamtexture colour but its not working.
Any tip where it come from ? and how do I fix it ?

[Svetlin.Nikolov]

Ah, this would probably be the foam under the liquid surface. Perhaps the Fog color of the V-Ray Mtl is too strong? Also, if you don't have it, please definitely place a VRayPlane or some other large geometry below the liquid to serve as a bottom - without it, the particles underwater that are affected by the V-Ray Mtl's color might not render properly.

Cheers!

[josh_gruitt]

Great! Ok I will do it. Many Thanks for all the help.

[josh_gruitt]

Hi, I've done more simulations, but still not quite happy with the result. It's almost there
The problem is when I have 2m Birth Threshold on the foam/split , its kind of missing water/foam/splash on the front, so does look like the foam/splash appears from the boat (image attached red circle). but when I have it lower 0.75 Birth Threshold then I have a really nice splash/foam on the front of the boat (image attached), However after few frames (around 200/300 frames ) it's starting to mess the foam/splash up creating foam everywhere (image attached) am I doing something wrong or is it a bug ? it's been a lot of consumed time waiting for around 300 frames simulation then to find out that it's not working.
Also I've tried with creating a simple box, changed the Phoenix properties of the box, so it wont interact with the water (image attached) and put it a really low Birth Threshold but I can't see any creation of Foam particles (image attached).
I can send the file if it will be easier to help me out. Many Thanks

[Svetlin.Nikolov]

Hmmm, the settings look fine. You are doing a regular Simulation, not a Resimulation, right?

[josh_gruitt]

Yes, I was doing a regular simulation.
Anyway, I've managed to sorted it out. It was on the because the Pure ocean on the Rendering setting it was on , that is why I had the foam on the front but missing the water, the water wasn't going up (maybe should be called Flat Ocean instead)
Now I have less foam but at least I can see the water so it's working. Therefore I don't need to do anymore the box birth.
I am doing more Sim, and I let you know. Many thanks for the replied.