- Tue Oct 02, 2018 10:51 am
It looks you are facing the worst situation for raytracers: caustics behind glass produced by small lights (big ligths would solve this problem). I would try hiding the glasses to Global Illumination (GI). That would cause them not to cast shadows, so some of the effect will be lost (the subtle shadows of the glasses), but the glasses themselves will look great and the render will be much faster. There are also tricks that generate some shadows, like duplicating the glass geometry, assigning an AGS material, hiding it to camera and refl/refr and moving it a very small distance so the faces are not coplanar; this will create shadows, but a bit fake.
However, in your case, I think you will have another problem: inside the glass boxes you have jewels, which you would also have to hide to GI too, otherwise, they would produce caustics (refractive and reflective) and you would have similar problems again.
Compositing different renders could be an option (probably the best looking and faster one): render the jewels without the glass boxes, the boxes without the jewels and mixing them.
Using extra-sampling for the boxes or the jewels could be an option too.
I hope this helps.