Having trouble with grainy renders

Fae3D

For the last couple weeks, every single render I make has been much grainier than usual.  I'm not talking about fireflies (white dots), what it looks like is just noise.  It is especially noticeable on skin and on water.

I have not made any changes that I know of.  I am using the exact same light sets I always have (mainly HDRIs, with SY Invisilights for added light).  The renders are bright, with plenty of light.  Adding more lights does not seem to make it any better, no matter how many I add.  Happens with portraits and large scenes.  I'm really confused about this, because it just came out of nowhere.  Literally, one day my renders were fine, the next they all rendered noisy.

I'm using Iray in the latest version of Daz Studio.  Mac OS Big Sur 11.7.3 with an NVIDIA GeForce GT 750M 2 GB.  Same thing I've been using for years and years.

Has anyone else seen this happen?  Was there some kind of update that I didn't notice?  

GhostofMacbeth

I am guessing that the Big Sur option (or some related option) dropped the CUDA options for the GeForce 750 and you are rendering CPU only, where you might have been able to run GPU in the past.

Fae3D

GhostofMacbeth said:

I am guessing that the Big Sur option (or some related option) dropped the CUDA options for the GeForce 750 and you are rendering CPU only, where you might have been able to run GPU in the past.

Hmm, interesting theory.  But wouldn't that just affect the speed of the render, not the quality?  I haven't seen any speed difference.

GhostofMacbeth

The iray renderer is based on how long something renders (in general). So if it is set to 5000 seconds at X speed with card X but it is changed to 5000 seconds at Y speed with card X  it could change how far it gets. You normally see most or the time refining at the end so that is where the clarity comes in place. I am on a Mac too so I have to figure out how to make it work the best I can. 

generalgameplaying

" I'm not talking about fireflies" - Apologies, flew over the "not".

 

Fae3D

GhostofMacbeth said:

The iray renderer is based on how long something renders (in general). So if it is set to 5000 seconds at X speed with card X but it is changed to 5000 seconds at Y speed with card X  it could change how far it gets. You normally see most or the time refining at the end so that is where the clarity comes in place. I am on a Mac too so I have to figure out how to make it work the best I can. 

Ah, now I understand what you mean.  Thank you very much for letting me know!  So I probably need to increase the render time, maybe?  I don't remember how to do that, is it very hard to do?

Fae3D

generalgameplaying said:

" I'm not talking about fireflies" - Apologies, flew over the "not".

 

No worries, easy to do!

ecks201

Fae3D said:

GhostofMacbeth said:

The iray renderer is based on how long something renders (in general). So if it is set to 5000 seconds at X speed with card X but it is changed to 5000 seconds at Y speed with card X  it could change how far it gets. You normally see most or the time refining at the end so that is where the clarity comes in place. I am on a Mac too so I have to figure out how to make it work the best I can. 

Ah, now I understand what you mean.  Thank you very much for letting me know!  So I probably need to increase the render time, maybe?  I don't remember how to do that, is it very hard to do?

On the render window there's a well hidden flyout menu. Look for a tiny arrow on the left hand side. You'll have the option to lengthen the render, without having to render the whole lot from scratch.

Peter Wade

I don't know about the Mac but on the Windows version of Studio if you look at the log after a render it tells you what device it used for rendering, This would tell you if you are rendering on the CPU. In Windows you can use the menu option Help->Troubleshooting->View Log File