Problem with rendering lights

Help and Troubleshooting
1

Hello everyone, I often make interior scene and I’m pretty bad with the lights. I have some “stain” or noise and I don’t know how to make them disappear.
I try to change rebonce and I have caustics off.
Can someone help me with that?

scene
scene.jpg3535×1986 2.65 MB

2

What is your lighting sources and what is your Lighting Mode set to? how many samples? CPU or GPU rendering?

3

Hi Matt. My lighting mode is interior mode (shadows:2 / rebonce:16 / GI on and rebonce GI:10).
Cpu rendering, (8 cores), 180 samples.
And I have a light source outside my building (radius 5 and brightness 1000) with white background, and inside, I have 12 spotlights. I tried to shut down the spots lights but I have still the same problem. When I look at the forum, it could be a “blotchy surface problem”?

4

I would disable caustics which most of the time is the main cause of the blotches. And if you used glass (solid), replace it with the more simpler glass.

I’m currently also busy with an interior and it works actually really well to go to the image tab and higher the exposure to something like +3 EV. That may be a bit too light but as long as you don’t get washed out whites it’s ok. Also be sure to to use ‘photographic’ in the same image tab. And put the image transform at ACES. Might look a bit boring but you can adjust the contrast a bit to make give it some pop or do it in post after rendering a EXR.

Short list of what I think helped my interior getting enough light…

  • put an area light in the window opening forcing more light into the interior
  • replace solid glass by normal, simpler glass
  • turn of caustics to prevent noise
  • use enough Global Illumination bounces (under lighting tab)
  • put image mode on ‘photographic’
  • put image transform on ACES, gives a pretty balanced image with playroom for post
  • if still dark/noisy, increase exposure to +3EV for example

Things I also try to prevent are materials with 0 roughness so if something is really glossy I always add a number even if it’s just 0.001 for example. Diffuse colors of 255/255/255 and 0/0/0 also don’t work in a renderer so I stay most of the time between 230/230/230 to 15/15/15 that gives some room for materials to interact with light.

Hope this helps.

5

Thank you for all this tips Oscar. Finally, the problem with the spots! And you’re right, it looks better when the white is over 230 :wink: