Please can anyone recommend me how to optimize interior scene in C4D with many light sources (many corona lights and objects with light material, but no sun or sky) to make it as little grainy as possible? There are tons of little white dots all over my scene. Thank you very much for any advice.
you need to find what is noisy and fix it, i think you have lights near bright material what produce noise so you need to fix via rayswitch material. All you find in this video.
Of cause for all question it is better to show screens and provide all info.
It looks like something is blocking the light, but it’s hard to tell without seeing the actual scene.
I think the best idea would be to contact us at https://help.c4d.corona-renderer.com/support/tickets/new
i would think that this is the nature of corona. it refines the picture with each sample pass. do you shine light through a glass window? i once had a problem where i turned on cuastics and i had black dots all over the floor where light shined through. use the frame buffer and do a region render. if it cleans up after a good while and you still see those, there is probably something funky in your scene that does it (material/lights). try isolate/delete objects in your scene and re paste them step by step. render only the bare minimum and gradually put in the stuff you need and give it a render everytime. focus on one area witha region render to speed up the process dramatically.
i do that whenever i have no idea whats wrong. this way you know relatively fast whats wrong.