I presume that if I have no transparent or translucent objects whatsoever, I can simply disable “refractive caustics” in the “light paths” settings of rendering, and it will make no difference to the render result. Am I right?
And will it shorten the render time, or make no difference there either?
If you don’t have any glass or translucent objects, I believe you’re right.
Hi, if you don´t need caustics you can always switch off Refractive caustics to get less noise for same sample count.
Cycles is very bad for caustics anyway so I switch it off per default.
Cheers, mib
OK. But when do I/don’t I need refractive caustics exactly? Am I right to assume that: no translucent objects, no refractive caustics needed?
And do I gain on render time this way?
Translucent and refractive materials work without caustics enabled. Caustics are needed when you want the refraction or reflection patterns to appear where light is focused. Think of loupe and the bright hotspot it produces. Don’t know the exact technical reason, but in render engines this effect is usually separated from global illumination bounces, reflections and refractions.
Hi, you need caustics only for glass objects, transparent and translucent materials does not produce caustics.
If a glass object hit a diffuse or glossy plane you need Refractive caustics enabled or the object render black.
simple_portal_lux.blend (782 KB)
Check this file and test with refractive caustic, default is disabled.
Cheers, mib
OK, starting to get it. Great example file mib2berlin!
So as far as my initial question was concerned, there is absolutely no need whatsoever for refractive caustics if there are no glass objects in the scene, that’s for sure.
Thanks guys!