KeyShot Forum

Technical discussions => Materials => Topic started by: imauserwiththisname on April 09, 2020, 01:49:57 PM

Title: Emissive Material - Black Artifacts Showing In Output
Post by: imauserwiththisname on April 09, 2020, 01:49:57 PM
Greetings All,

I'm sure I am overlooking something simple with my setup, and looking for some advice.

Using the emissive material hidden to camera trick to render out some ground shadow only views to layer in PS, and when rendering these images out, they render with the black artifacts seen in the attachment.

These artifacts don't show in the live view, so wondering what setting I may be missing.

Please advise if possible!

Thank you!

KeyShot 9.2 Pro - 2560 x 1600 - 16 Samples - 8 Ray Bounces - Global Illumination (and cache) - Off
Title: Re: Emissive Material - Black Artifacts Showing In Output
Post by: richardfunnell on April 09, 2020, 02:35:28 PM
Looks like you need to bump up your ray bounces, potentially pretty significantly. The light bounces have to go through multiple layers of overlapping parts, otherwise they show these kind of black artifacts. Luckily it should be pretty obvious once you crank them up.

Keep us posted if that fixes it or not.
Title: Re: Emissive Material - Black Artifacts Showing In Output
Post by: TGS808 on April 09, 2020, 07:01:59 PM
Richard is (as usual) 100% correct. I encountered this some time ago while doing the exact same thing you are doing now (shadow only renders). In the Lighting tab, Ray Bounces defaults to 6. Change it to 200. It will eliminate all those black artifacts and won't add any extra time to your render.  These black artifacts started showing up in KS8 (while doing this "hidden emissive for shadows only technique"). It never happened previous versions.
Title: Re: Emissive Material - Black Artifacts Showing In Output
Post by: imauserwiththisname on April 10, 2020, 01:26:22 PM
Thank you both—bumping up the ray bounces did the trick!

I appreciate you both sharing your expertise.