OTOY Forums

Hey everyone,

Just to let you know: I have little to no experience with indoor lighting.

I just started this scene which has basic daylight environment and two fairly big emitters on the ceiling (you can see them in the attached pic). Somehow I can´t get the grainyness out of the image. I´ve attached pics of the scene as well as my chosen render settings. Anyone has suggestions on how to fix this?

best wishes

Hi, your max samples need to be higher than 500. Maybe 2000 perhaps?

Thanks for the suggestion, tried it with 4000 and it looks a lot better, still some grain in the dark areas though, but maybe that would disappear with even higher numbers...suggestions?

The samples you need to render to depends entirely upon how clean you want the image to appear, along with the variables of every surface type and light source in your scene, in addition to which kernel you are using for what. Each is faster at something specific.

There is no magic number. General rule of thumb, the bigger and more complex the scene, the more samples to render a clean image. It is literally, adjust up until you feel there's no point in continuing, since a render is never technically finished, you just stop it when you decide to. There's also no harm in starting at a low guess, then adjusting the number of samples up from there in increments, as it doesn't alter anything unless you alter something in the scene or kernel settings, and will pick up from where it is.

dark areas always resolve last, meaning they need more time to become sharp...if ever. The more light an area has the faster it will be clear. Indoor environments and heavily shaded areas will always need more time to render.

One thing I do is use the hotpixel removal feature to help with this. a setting of 1 = off and a setting of 0 = on 100%. And you can do a decimal value. What I don't like with the hotpixel feature is that it can blur parts image that were actually sharp, and the hotpixel setting is for the entire image. so I have a way to get around that.

I save the image without the hotpixel setting enabled.
then save a new version of the image with the setting enabled.
Then in PS i layer the two images, and mask out the hotpixel version of the image to only impact areas I want.

I rarely want to let something render for more than 4000 samples, and occasionally you get an image that just needs more time. But using the hotpixel setting can help if you can allow for the area not to be super sharp. And sometimes the hotpixel setting being enabled doesn't even negatively impact the sharper areas of the image, so it's always worth testing IMO.

You could also try changing the dark wall material to a lighter colour which would brighten the scene and possibly improve the resolution.

Spectralis wrote:You could also try changing the dark wall material to a lighter colour which would brighten the scene and possibly improve the resolution.

if the client allows for it lol. But yeah that would definitively lighten the scene and probably bounce more light around that region. the color of walls makes a big difference in many scenarios.