How to render white water in the right way and create Render passes for White water

[Daniel16_16]

Hello

I am working on a Ocean scene with a flip tank integration. Now I have rendered out the ocean with the flip tank simulation. And now I want to render the white water.

But a few frames after the white water simulation started rendering, the rendering process just keeps crashing, and I dont know how to fix it. Or I do something wrong? 

Should I cache out the white water first and then hit render or how? And how I can create render passes of the white water, so I just can overlay the different render layers in a compositing software on each other and I dont need to mask it out somehow... 

Help would be much appreciated!!

also, I have used the pop advect by volumes node and the bounding box is cutting away some of the white water, how can I fix this too????

Thanks!

Edited July 2, 2021 by Daniel16_16