can someone give me a briefing on the Iray render list parameters?

Toobis

Any chance someone could give me a basic terms briefing on what each of the following parameters means from the Iray render option list?
try and keep explanations simple please:

 

Min Update Samples

Min Samples

Max Samples

Rendering Quality Enable

Rendering Quality

Rendering Converged Ratio

Post SSIM Avaliable

margrave

Min Update Samples: How often the render window is refreshed after running some iterations.

Min Samples: Minimum number of samples before a render can quit.

Max Samples: An Iray render can theoretically continue forever, getting incrementally better. This caps the number of iterations, at which point the render quits. Like Max Time, set it to -1 to make it go indefinitely, so you can quit it manually when you decide it looks good enough.

Rendering Quality Enable: Although a render can continue forever, eventually it plateaus and there's no noticable difference in quality between iterations. This option will do some algorithms to check the quality and end the render if it's good enough. I always disable this and eyeball the quality myself.

Rendering Quality: Higher number, higher quality before a render is considered done.

Rendering Converged Ratio: How close to the theoretical photoreal image you want the algorithms to check for. 100% is impossible, since that woule require a near-infinite number of light rays. Set it to 99%, at most.

Post SSIM Available: A kind of AI denoiser that's been trained to detect when a render is done. Utterly worthless, don't use it.

Toobis

margrave said:

Min Update Samples: How often the render window is refreshed after running some iterations.

Min Samples: Minimum number of samples before a render can quit.

Max Samples: An Iray render can theoretically continue forever, getting incrementally better. This caps the number of iterations, at which point the render quits. Like Max Time, set it to -1 to make it go indefinitely, so you can quit it manually when you decide it looks good enough.

Rendering Quality Enable: Although a render can continue forever, eventually it plateaus and there's no noticable difference in quality between iterations. This option will do some algorithms to check the quality and end the render if it's good enough. I always disable this and eyeball the quality myself.

Rendering Quality: Higher number, higher quality before a render is considered done.

Rendering Converged Ratio: How close to the theoretical photoreal image you want the algorithms to check for. 100% is impossible, since that woule require a near-infinite number of light rays. Set it to 99%, at most.

Post SSIM Available: A kind of AI denoiser that's been trained to detect when a render is done. Utterly worthless, don't use it.

 Ok thx. What would you use to increase general all round quality of a render from these please.

margrave

Toobis said:

 Ok thx. What would you use to increase general all round quality of a render from these please.

Max Samples: -1

Max Time: -1

Rendering Quality Enable:  Off

Spacious

It's useful to know that the render will stop when it reaches the first of any limits that you set.  Also that some scenes take hours and still haven't reached a a high quality or convergence ratio, while actually looking great, and others will reach a high quality or convergence ratio quickly, but still not look that good.

In my opinion, not that it's vauable or anything, the default render settings produce absolutely fantastic renders provided that there is sufficient lighting and that the scene fits on GPU vRAM.  If the render gets kicked to CPU it generally needs way more time than the default time setting to get even close to any of the other thresholds.

Edit to add : I almost always render at twice the size I really want, run it through a denoiser afterwards, blend the denoised with the original, and shrink the result, for whatever that's worth.