Glass jar render in Cycles


Recently we have started working on cycles render engine, we are upgrading the old models which we had done older versions of blender.
The models are of Physics and chemistry lab equipments.
The problems is at the base of the render output.
As it is seen in the render output the base of the object comes dark I tried changing world background, IOR, light setting but nothing seem to work.
I have attached the blend file and render image.
Please any suggestion or help would be very great.

Thank you.


glass4.blend (523 KB)

It’s because you have “no caustics” checked. Uncheck that and you’ll get a lighter base.


Yes, that was “No caustics” (that must be removed from GUI, too many confusions), and do not use point , sun, spot lights with glass materials. Use only background or mesh with emission, they are can not be sampled from bounce after hit with glass or perfect mirror. I think ideal is HDR background texture for that setup.

Ambient occlusion with ray traced glass looks odd too, and prodcue artefacts (overbright background).

Slightly of topic
Quick question to storm_st: Why should “No caustics” be removed from the GUI?? It’s a perfectly viable and useful option to have. Just as “Shadows” under Transparency.
There’s a lot of options that ran be confusing (not only in Blender, in commercial software like Octane etc too), but 99% of them have good uses. The artists just needs to learn how to use/what they do (definitely not saying that everyone needs to be experts, but if you are serious about 3D/graphics you need that kind of knowledge too).