Interactive Render shows different result than Final Render

[nicolas7755]

Hi everybody

I'm currently working on a bathroom scene.
It's lighted with an HDRI and a couple of rectangular CoronaLights, most of them are invisible, with zero visibility in reflections, refractions and don't occlude other lights.
While I'm still in the interactive rendering, this works like a charm. But as soon as I render the final image, weird black artifacts start to appear. Turning off the artificial lights makes the artifacts go away.

Any idea on how to get rid of this?
Thanks in advance for your help

Best,
Nicolas

[TomG]

First thoughts - is this 3ds Max or C4D? Also, is IR set to force Path Tracing, and the final using UHD Cache?

[nicolas7755]

Hi there

Thanks for your reply and sorry for the incomplete information.
I'm working on 3ds Max 2017 with Corona 1.7.

The final is indeed using path tracing as primary solver and uhd cache as secondary, but force path tracing in IR is turned off.

[Ondra]

Looks like NaNs - can you share the scene with us? Can you also right-click the black places and tell us if there is number listed as pixel color, or NAN?

[nicolas7755]

Hi Ondra

If I right-click, there are numbers as pixel colors listed. So it's probably no NaNs.
I'll try to upload the scene tonight!

[maru]

Are you using the "new light solver" here? (checkbox in performance tab)

[nicolas7755]

Hi maru

No, I don't use the new light solver.

I figured out now, where the problem came from:
For some reason, I had a refraction override active, which caused the artifacts.

[maru]

Hmm... that's strange the use of new light solver should be one possible difference between IR and regular render.
Another one might be the enviro solver?

Could you send us this scene anyway? (or a part of it, with the problem present)