Simple caustics and glass test

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?

What’s your caustic depth on the photonlight like?

Also I get the impression that you’re mirroring way too much…

I believe that’s what Cdepth is fudje.

My guess would also be that you’ve got these settings too high. That could be a cause of the artifacts. I would set each to around 3. The other thing that may cause them is that your spheres are not subsurfed enough. The “facets” of the sphere’s geometry might effect the caustic appearance(?)

Also, do you have GI turned on?

The caustic bounce depth for the photon light is set at 14, equal to the CDepth setting in the Yafray render panel.
I didn’t think about the mirror settings, thanks for that.

Yes, I set CDepth at 14. But Fudje was talking about the caustic depth for the photon light, which I neglected to mention in my first post.

Yep, GI is set to “Full”. Quality is set to “High”.
You’re right about the settings being too high. I had first started testing with Depth and CDepth at 10 each. They looked quite alright, there were artifacts but not as strange-looking as the ones in the image I posted above.

Thanks for all the suggestions.