Author Topic: Emissive Material - Black Artifacts Showing In Output  (Read 740 times)

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Offline Lookwright

Emissive Material - Black Artifacts Showing In Output
« 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

Offline richardfunnell

Re: Emissive Material - Black Artifacts Showing In Output
« Reply #1 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.

Online TGS808

Re: Emissive Material - Black Artifacts Showing In Output
« Reply #2 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.

Offline Lookwright

Re: Emissive Material - Black Artifacts Showing In Output
« Reply #3 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.