Black Artifacts with refractive materials

Hi, I’m sure you all have heard this question before but I just can’t figure it out. How do I get rid of the black artifacts that appear on the glass and refraction shaders. I have tried to increase my transparent and transmission light bounces but it is not working :spin:. I know that there is a trick with the ray depth input of the light path node but this cuts the quality of the render :frowning: Can someone please tell me what to do?

One small trick to avoid the endless bounces of the total internal reflection, is to change your glass into transparent a few bounces earlier than the max transmission bounces…
You can use the ‘ray depth’ and a math node set to ‘is greater than’ to drive the glass/transparent mix.

Thats the trick that I mentioned in my first post. Problem is it messes up the caustics and I am trying to create a shader with dispersion and this trick deletes the dispersion. Is there another way?

Dispersion is the worst case scenario in cycles… There’s lots of energy loss when using current technics for dispersion, and room for more artifacts than with a simple glass.
In scenes like the one you describe, you may need to split the scene into different layers (3 layers for the glass RGB, and 3 layers for the Shadow/caustics RGB), and combine everything in post.

Cycles is not suited to deal with this, so don’t expect to be able to render such a scene in just one pass.