Why Do Renders Look so Grainy?

terryspear

[Why Do Renders Look so Grainy?] Sometimes they're not too bad, but other times they're just awful. And I don't know what I'm doing wrong!

Edited for Please put your question in the post body and the title - Daz 3D Forums

Richard Haseltine

Some (ToS friendly) examples might help, but a couple of possibilities:

you may simply be running out of GPU memory and dropping to CPU on some but not others; depending on the scene the default time for a CPU render (2 hours) may not be enough to eliminate noise while GPU is fast enough to complete

it may be lighting - if the scene is heavily dependent on light from limited sources bouncing into shady corners then it can take a long time for those areas to full converge, and again your render may stop at the two hour mark rather than at completion with an easier to converge light set up.

it's also possible that materials may be against you (a lot of very shiny surfaces can make each pass take longer, agains leading the time out rather than completion; some materials are just more complex to calculate or simply take mor steps to converge).

onix

Either you forgot to turn on the denoiser (which is not turned on by default if you start a new scene) or your rendering is going in the CPU mode entirely or possibly your GPU ran out of memory and even if it continues to render denoiser does not work anymore.

Usually at this time noise should never be an issue you will mostly have other problems like lack of picture detail like highlight /reflections or hair being too smudgy