optimizing for a lot of tiny refractions

[cgdom]

I'm dealing with a scene that has some subsurface material with a bunch of salt crystals on it (populated with xgen). The object itself is simple, but because the crystals have reflections and refractions, and there are a few thousand of them, the render times get very high. Turning of refractions/transparency improves render time a lot but obviously kills the look. Is there anything that can be done to optimize in such a scenario ? I only need the crystals to refract a little of the surface they are sitting on and not anything far away in the scene.

[SonyBoy]

It's possible to set up reflection exclusion groups (not sure if refraction has a similar capability), so that certain objects only reflect certain others. However, sounds like that's not feasible in this situation. Off the top of my head a hack might be to render the crystals in a separate pass and remove the SSS calculations or even use a stand in shader on that object. I'm assuming the SSS is not particularly important or visible in the refractions but is likely bumping up your render times significantly. If you can get a good enough result without it that would be worth a try.

Seriously, this new font sucks big time.