Foam outside simulator - too bright

[tomastnt]

Hallo
I have a problem with foam that goes outside of the simulator. As you can see, it is too bright and also too much visible in alpha channel. I wonder if it is because underwater bubbles etc? I am using 3.12.00 version and vray 3.6. The scene for 3ds max 2017 is available to download it here:
https://www.sugarsync.com/pf/D7185189_08989657_64436338

and cache file of frame 300 is here:
https://www.sugarsync.com/pf/D7185189_08989657_64436452

[Svetlin.Nikolov]

Hey,

Looks like the foam inside the simulator is a little below the liquid surface, almost the same as this thread from just last week, and I would recommend the same solution: https://forums.chaosgroup.com/forum/...m-outside-grid

Regarding the alpha - if you are not already rendering in Point mode of the Particle Shader, switch to it, and there you have the option to control the Point Alpha. You can also control the Shadow Strength of the points, and this will help you get better looking volume of the foam.

Cheers!

[Gosho.Genchev]

Hey, just to add to what Svetlin's already mentioned - if the foam is still too bright after tweaking it with the Particle Shader -> Vertical Offset, try reducing the Diffuse Multiplier.

I'll also mention that you may end up with very uniform-looking blob of white if you accidentally turn OFF the Affects Shadows option in the Refraction tab of the V-Ray material and the Disable Liquid Shadows on the Particle Shader. Looking at your screenshots, your setup looks fine but I'm mentioning this just in case.

Also, if you insist on the Bubbles render mode (could be wrong here but I'm seeing some reflections there) - a couple more bounces and a nice HDRI instead of the V-Ray Sky should give you a very nice result although it will take quite a while to render =). The Vray Sky is uniform blue so no interesting highlights in the reflections as a result.

Cheers!

[tomtnt]

Hey, thanks for direction to solve my issue.
It is not commercial project, so I play with it in my free time. Anyway, I have made some changes and test today. I am still quite confused from the results. First of all, just the change from bubbles to points visually solved the problem. But I still think it is not right. Btw with my original scene setting I have lost nice details in the foam I think - it looks to uniform now.
But I am more confused of the original problem with too bright particles out of the simulator. I have switched particle shader only to underwater particles. This way I have found that these particles are above the water surface when go outside of the simulator. So I told myself I can lover them by shift value. When put extreme value -10 meters, the particles are under water, but shading these particles are still different. Why is it possible? All of them are under water now, so all of these particles should be shaded similar?

Second think I don't understand is the way how phoenix separate under water or above water particles - especially when foam is outside of simulator, there are stripes of foam - is it normal way how phoenix works?

Only under water foam + shifted -10 m


Only under water foam + shifted ocean floor to get visible shadows of foam


Only above foam


All types of foam


only underwater foam

[Svetlin.Nikolov]

Ah, watch out - if you don't have a bottom plane or geometry under the ocean, you will hit a V-Ray limitation with vraymtl with fog color + one-sided geometries such as the ocean mesh + volumetrics (such as the Phoenix particle shader). You need to close off the bottom of the ocean with a layer of geometry in order to make it right and get predictable results.

Please check if this helps. Cheers!