Disable reflexion in a cycle material

Hi every one!

I’m trying to make a realistic black hole with cycle…

The problem is that as soon as I do something transparent with refraction (either with glass or principle) I get a slight reflexion on my surface. Even if I have no specular or metalicity… If I use roughness not only will it keep a blury reflexion (wich my black hole will not be black), but my refraction get blured too. Anybody has an idea?

Thanks in advance!

If you want refraction only, use a refraction BSDF.


I have been struggling for true transparency as well. Trying different options, I luckily found one that works. Probably it is not the best, but it does the job and you can adjust the transparency from 0 to 1. The file I use is just an empty file (alpha).

As mentioned already, use pure refraction instead. Glass and principled simulate a glass like material, which is a fresnel mix of refraction and reflection - hence there will always be reflections (for IOR>1). Don’t use refraction roughness though, and tweak, possibly map the IOR to say how much light is bent where. I don’t need any black holes in my regular work, so I’ve never made one in Blender, but I’m pretty sure tutorials exists.

Sorry for late answer, my job is very time consuming lately!

I tried and it works perfectly! Thanks!