Grainy area light with other objects

[snaffy]

Hello everyone, I'm having a problem with lights...If you look at the first picture I have an area light on a flag....I am happy with this. Now without changing any settings....I just turn ON the visibility of the buildings in the background and the quality of the light is terrible (pic 02) keep in mind I have changed nothing except turn on the visibility of buildings....Can anyone let me know why this is happening? I am using c4d18 and octane 3.07-R2 and using GI Diffuse. Thanks!

[bepeg4d]

Hi snaffy,
the images are not visible, so difficult to understand what’s going on.
Please, use the Upload attachment button while editing your post.
ciao Beppe

[snaffy]

OK that scene is probably too complicated. I have attached a very simple scene. With an area light sphere and tube. The tube has a texture emission texture. Now when the tube is turned off, the area light looks as it should. When the tube is turned on it looks terrible. Does anyone know why this is happening or how I can fix it, even upping the samples to crazy numbers doesn't help. This is driving me nuts!!!

[niestudio]

OK that scene is probably too complicated. I have attached a very simple scene. With an area light sphere and tube. The tube has a texture emission texture. Now when the tube is turned off, the area light looks as it should. When the tube is turned off it looks terrible. Does anyone know why this is happening or how I can fix it, even upping the samples to crazy numbers doesn't help. This is driving me nuts!!!

The attachment example.jpg is no longer available

The attachment screenshot.JPG is no longer available

You have very low render samples.
Have you tried rendering with higher samples, and turning on Adaptive sampling?
Also, did you realize how big that tube light is? It's radius over 1000 Miles. I've never worked with anything that large, perhaps there are special settings needed.

[aoktar]

+1
It's too big. Try to make it down-scale.

[snaffy]

Thanks for the feedback!!....yes tried adaptive sampling. I do realize the settings are low but that's not the problem....it's the tube or any very large illuminated objects with extra area lights in the scene.

I made the tube that size because it's similar to what I'm dealing with....A very large city with texture illuminated buildings...and I need to focus on small items within the city that require area lights to illuminate them (like the flag from the original post). It seems that having these very large illuminated objects in conjunction with the area light seems to be the problem. Because once I scale down the tube (or buildings) significantly the area light works as you would expect.

Do you think there's any solution to dealing with this? (without just not using large illuminated objects, because I can't delete the buildings or scale them down) Thanks so much

[niestudio]

you could try unticking cast illumination or Visible on diffuse / Visible on specular (depending on your version) for your emission texture.

It just seems like you're setting yourself up for other problems with stuff that size.

good luck