FOAM R&D

Getting closer to a more detailed Krakatoa-type look for the foam. Currently the sim has +20,000,000 particles and cache sizes are approaching 1.2 GB per frame, which makes it a challenge to manage on the renderfarm. The render time for the foam by itself is only 2-3 minutes, but when rendering the ocean surface as a holdout it goes up to 10-15 minutes due to the displacement of the ocean mesh, and loading the geometry. I have reduced this time by writing out the mesh and loading it on to the farm, but I need the space to hold the cache files so for now I am offloading the mesh generation to the farm.  

Front foam with no ocean matte (downloadable) 20,000,000 particles

Foam: rear view

With ocean matte

Current Foam Technique:

For this version I used a combination of methods. I used the particle generation system of the white water solver with some customization added for external forces (wind), a curl noise vop, and vaporization (vop) for the spray. I also used and attribute that normally gets deleted in the solver called "foamdensity", which allows you to create a fit expression, that when multiplied by the pscale can have the effect of reducing the pscale to almost zero in areas of low density. This results in more defined foam patterns and reducing the visibility of individual particles between foam clumps. 

Lots of particles
To get the fine particle appearance I used a pscale of 0.05 as a starting point, then added variation based on density. After that, I cranked up the particle amounts to over 20,000,000.  

Isotropic Volume Shader
Based on the feedback, I decided to use a completely different method to shade the particles. Instead of using the particle replicate along with the VDB + rasterizer that comes default with the whitewater tool, I used a custom shader, which utilizes an isotropic volume method, which seems to be better able to maintain the detail, and avoid the smokey look I was getting before.  

Separating into layers
To get more detailed sims that are more manageable and easier to art direct, I have begun to separate them into layers. This will also allow customization of the velocities, for example, on the front independent from the trailing foam in the wake.  

Color Variation
More color variation will be added using color by velocity and vorticity fitted to color ramps and added to the shader.

Foam wake (downloadable)

Turntable no car