I was just muddling around with glass and caustics using Yafray, and decided to stretch the capabilities of the renderer somewhat.
14 clear glass spheres. Stacked with 9 at base, 4 in middle, and one on top. Sitting on a very plain plane. Lit by sun light from right of camera, with a photon light from corresponding direction, shooting 900000 photons.
Raytraced mirror depths and transparency depths are maxed out at 10. Yafray setting’s Depth at 15, CDepth at 14. Some photon mix and blur tweaks to smooth out the caustics effect.
The strain shows. There is some kind of light banding between layers, and strange shadow artifacts within the spheres. Any ideas on how to correct those? Or have the renderer really reached the end of its leash?