Convergence Quality Percentage?

nonesuch00

I am using DAZ Studio 4.22.1.41 Public Beta and my new PNY GeForce RTX 4070 GPU to render an old 2K square iRay scene. The scene is set to stop at 5000 iterations or 95% quality convergence. It stopped rendering at 687 iterations claiming the quality convergence has been reached. It took 5 minutes 30 seconds including load time.

2023-12-27 14:19:55.679 Iray [INFO] - IRAY:RENDER ::   1.0   IRAY   rend info : Received update to 00681 iterations after 04:32.503.
2023-12-27 14:19:56.258 Iray [INFO] - IRAY:RENDER ::   1.0   IRAY   rend progr: 95.39% of image converged
2023-12-27 14:19:56.303 Iray [INFO] - IRAY:RENDER ::   1.0   IRAY   rend info : Received update to 00687 iterations after 04:33.128.
2023-12-27 14:19:56.304 Iray [INFO] - IRAY:RENDER ::   1.0   IRAY   rend progr: Convergence threshold reached

 It looks OK at 95% convergence to me but I have a lot of floaties in my eyes for decades so maybe that floaties noise is interfering with clear evaluation of the render results.

What is the "official" render quality convergence percentage that paid professionals use in DAZ Studio / iRay? I know there must be some generally professionally accepted percentage quality just like with sound compression file formats. 

Also, is it my imagination or is iRay using some sort of much improved AI built into it's RTX cards & iRay to get better results faster in DS Public Beta 4.22.1.41? 

Richard Haseltine

There isn't an official value - a pixel is converged (in had-wavy terms) when its value over successive iterations stays within a certain range, the size of the range being set by Render Quality. How much convergence an image needs will depend on the image - soem areas (shadowy nooks thata re hard for light to reach, eyes with more complex interactions than most surfaces) may remain noisy after the rest of the scene has settled and when those areas are noticeable it may be that the scene will require a much higher overall convergence (ratio, quality, or both) or the use of the spot render tool to ensure that those areas are given due weight.

They are not new features, but Iray has denoising and a new completing threshold that both depend on being rendered on the GPU (rather than the CPU) and on an RTX-level hardware (it isn't RTX cores, though, as I recall) - you may be seeing the benfits of soemthing you had on but which was not actually being used on your old card.

nonesuch00

OK, thanks, then I'll stick to 95% for iRay renders in DS.

fearthefailure

You can turn that off and go for longer renders for even higher quality results.  I was taught to do that, and I'm VERY happy with the results.  Rendering Quality Enable = Off > Max Samples = whatever you need > Max Time (secs) = however much time you can afford to wait.  I usually set mine at 1800 seconds zoomed out / 5400 seconds zoomed in.

nonesuch00

fearthefailure said:

You can turn that off and go for longer renders for even higher quality results.  I was taught to do that, and I'm VERY happy with the results.  Rendering Quality Enable = Off > Max Samples = whatever you need > Max Time (secs) = however much time you can afford to wait.  I usually set mine at 1800 seconds zoomed out / 5400 seconds zoomed in.

I will try that on the next 4K realistic portrait I attempt, thanks.