Foam above water

[jstrob]

Hi I have a beach scene where the foam seems to be a littel bit floating above the water. is there any settings to lower the foam layer? A bit difficult to see on a single frame but in motion we clearly see that foam is floating in the air like at 2 or 3 inches.

Maybe surface lock???

[Svetlin.Nikolov]

Yup, sounds like you need more surface lock - how much do you have now? Additionally, there is an option in the Particle Shader allowing to offset the entire particle system vertically

[jstrob]

all right thanks i will try that. I had 0,5 for surface lock I just launched a sim with 0,9 but maybe it's easier with the shader. ha yes "vertical offset" in the shader!!

[jstrob]

Finally the vetical offset in the shader is not a solution. When I used it to move the foam more on the surface where it is floating above, I loose too much foam on the shore of the beach and everywhere where the foam was ok. i would need a setting that just make everyting on the surface and not just lowering or elevating everything above or below the surface.

[Svetlin.Nikolov]

Hey Strob,

Can you send me the scene so I can check what's wrong?

Thanks!

[jstrob]

Hi Svetlin,

I have another scene where the problem of foam above the ocean displacement is even more impossible to fix. I don't understand why when we use displacement on water the foam is not sticking to the surface like a few years ago it did.

Like in this example that I did a few years ago, the foam was displaced by the ocean waves (generated by displacement):
http://www.phylacterecola.com/strob/...v007_small.mp4

Now when I try to do something similar it looks like the foam is not affected at all by the displacement. Why?

And sorry for not seding a scene previously, I couldn't share my production scene and didn't have time to created another one from scratch.

But basically it's just:
create a water sim with an animated character swimming.
add ocean displacement high enough
try to simulate with foam

the foam will not be affected by the displacement at all.

also the simulation itself is simulated on a flat surface and then distorted by the displacement in a way that it doesn't fit with the character interaction.

[flipbook]

Hey Strob.. seems to work as expected here. Basic flat sim with a torus knot 'swimming' through. Add the displacement, phx foam (link the phx foam to the sim) .. render and it follows the displace. I would imagine it would not respect the areas of your character as it is just a simple displacement applied on top of the sim. Maybe use the displace fall off based on the character?

[Svetlin.Nikolov]

But basically it's just:
create a water sim with an animated character swimming.
add ocean displacement high enough
try to simulate with foam

the foam will not be affected by the displacement at all.

Hmm, this does not sound like the original issue from the thread. There are two possible reasons at first thought why you don't have foam displacement at all:
- The Particle Shader's Liquid Simulator slot does not point to the simulator. The particle shader won't be able to acquire the displacement data from the sim, and so the mesh will be displaced but the particles will not be.
- The displacement fade-out settings are suppressing the displacement at places where you don't want this to happen - this will visibly affect both the mesh and particles - https://docs.chaosgroup.com/display/...g-Displacement

We actually did expand the displacement fade-out section even more in the nightlies, so now you have separate controls for:
- suppressing displacement away from the ocean level.
- suppressing displacement where the liquid moves with high velcity
- suppressing displacement near a geometry.

With a latest nightly you can use any combination of these, and also it's easier to turn all of these off.

Note that the scene scale and the grid resolutions are also vary important, so without seeing the settings and scene I won't be able to say more...

[jstrob]

Ok thanks all. I will try with a simple scene and share it here.

[Svetlin.Nikolov]

Thanks, Strob! Cheers!