In the “Liquid – Hybrido” shelf you can find two tools for synchronizing your foam simulations with the core fluid's displacement (“Ocean Statistical Spectrum”), and the Hybrido mesh. When we talk about “foam” here, we are referring to the following HySPH emitters are concerned: “Foam”, “Splash & Foam”, “Bubbles”, “Wet & Foam”, “Waterline”. In the combined emitters, only the foam particles are affected by these tools. They replace the graphs which have been used in the previous version, although these graphs are still available under RealFlow's “Demo scenes”.
The idea behind these tools is that the basic secondary simulations do not take the core fluid's displacement into account and you will see an offset between the HySPH particles and the fluid's surface respectively in the Hybrid mesh. To close this gap, the tools evaluate the displacement structure and reposition the particles to match the surface waves. This is a non-destructive process where the original files will be kept and not overwritten.
On the first look it seems as if both tools are doing more or less the same, but there is an important difference. The “Displace Foam Particles” tool is very fast, because all it does is to evaluate the core fluid's displacement and to reposition the particles. When you create a mesh this process might not be accurate enough, because it does not consider all the parameters you can apply to the mesh's displacement structure, e.g. velocity or height attenuation.
When you use the “Snap Foam Particles” the tool will evaluate the mesh's geometry and places place the particles on top of the mesh. This is a very nice and convenient feature in cases where you want to render all elements (mesh and secondaries) together. But, it is much slower, because this it is a computationally expensive process..
For both, “Displace Foam Particles” and “Snap Foam Particles”, the workflow is very similar.
Displace Foam Particles
“Displace Foam Particles” requires a cached (= existing) simulation of a secondary foam-type emitter. The domain, on the other hand, doesn't require any cached particle data – only the its “Ocean Statistical Spectrum” feature has to be active, because this information is used to displace the particles.
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