# Black holes / Water in glass

I try to render mineral water bottle filled with water in Cycles. For testing purposes I use super simple model with absolute flat lighting filled with white color.

What is bothering me are the black spots on the render. I mean, I know there should be some strange curves generated by IOR, but in the complete white environment black patches shouldnt appear.

What should I do, to avoid them? Im attaching images with the render result.

I know that lighting and model are dull, but I use them to exclude any unnecesarry factors. My render settings are:

This is my latest bottle atempt with photo lighting. It looks better, but on the top of the bottle strange curves appeared. I think that it is caused by plastic rings on the bottle, but it look unnatural. I think that Im missing something, because I still dont have control on this render behavior.

• Maybe related - blender.stackexchange.com/questions/7864/…. Also blender.stackexchange.com/questions/2558/… – Mr Zak Sep 26 '16 at 9:43
• – user1853 Sep 26 '16 at 14:04
• I'd say this result is normal. My guess: it's caused by the refraction from the bottom of the cap. – Delagone Sep 26 '16 at 14:59
• – iKlsR Sep 26 '16 at 19:08
• Ive seen all this articles. In fact, the bottle I created as a result of the last tutorial (adaptivesamples.com). Unfortunately, it doesnt solve my problem. – Andrew Sep 27 '16 at 6:36