I'm missing something with Iray finishing prematurely.

To be clear I am doing 100% CPU renders. It seems regardless of what I try, what I set my Renders will eventually stop.

I have max time set to 259200, is that nano-seconds? 

What do I need to do to just have this thing going and going until I manually stop it?

Comments

  • scorpioscorpio Posts: 6,454

    To be clear I am doing 100% CPU renders. It seems regardless of what I try, what I set my Renders will eventually stop.

    I have max time set to 259200, is that nano-seconds? 

    What do I need to do to just have this thing going and going until I manually stop it?

    Try setting the max time to 0, and increasing the max samples - I usually unlock limits so you can go very high.

  • SpottedKittySpottedKitty Posts: 6,470

    Don't forget that there are three stop conditions for an Iray render; time (default 2 hours), samples (default 2000), and convergence (default 95%). The time and samples can be ignored by setting them to zero. Whichever active limit is hit first will stop the render. There's also a Quality setting (use with care, I've never set this higher than 2 or 4).

  • scorpioscorpio Posts: 6,454

    Don't forget that there are three stop conditions for an Iray render; time (default 2 hours), samples (default 2000), and convergence (default 95%). The time and samples can be ignored by setting them to zero. Whichever active limit is hit first will stop the render. There's also a Quality setting (use with care, I've never set this higher than 2 or 4).

    I turn it off.

    You can as SpottedKitty says set the convergance higher if you set it to 100% the render and Samples and time to 0 I believe the render will run forever or until yu stop it.

  • SpottedKittySpottedKitty Posts: 6,470

    Convergence shouldn't be set to 100%. You can get very very close to 100% — I use 99% for a moderately high value, and I don't go higher than 99.9%. You can add more nines if you want, to see if that improves the render appearance, but note that this will increase the render time. It might increase the time by a lot.

    Actually, I don't think the Convergence can be set to ignore like the others (unless a 0% value does it).

  • scorpioscorpio Posts: 6,454

    Convergence shouldn't be set to 100%. You can get very very close to 100% — I use 99% for a moderately high value, and I don't go higher than 99.9%. You can add more nines if you want, to see if that improves the render appearance, but note that this will increase the render time. It might increase the time by a lot.

    Actually, I don't think the Convergence can be set to ignore like the others (unless a 0% value does it).

    From what I could gather why it shouldn't be set to 100 is because it will, at that level, never reach a stop point; and as the OP wanted to render until he was ready to stop the render this would probably work, the OP's goals was to increase the rendering time.

  • StratDragonStratDragon Posts: 2,838
    edited May 10

    Iray is most certainly faster than Lux on CPU and the integration with DS is great but I'm still trying to find clear documentation on what those settings mean. I've found tutorials on the web but as another poster here mention they usually are written "this appears to be", or "this might be" 

    for instance; what is Spectral Rendering? It has it's own tab. What happens if it's unfaithful? Should I be speaking to a counselor about my Spectral Renderings unfaithfulness?

    Post edited by StratDragon on
  • TheKDTheKD Posts: 1,248
    edited May 11

    Try it out, it's hard to explain lol. The end results with spectral on, the colors come out different. It's almost like cranking up vibrance in photoshop if you are familliar with that. Not sure how much of an impact it would have on render times with CPU, but in GPU render times were impacted very little in the little experiments I did.

    Post edited by TheKD on
  • chris-2599934chris-2599934 Posts: 934

    This two hour(!) video explains what all the iray render settings mean in some detail. Well worth a look:

    https://www.youtube.com/watch?v=ibricWdVQg0

  • JonnyRayJonnyRay Posts: 1,668

    I was just about to link that same video, Chris. :)

    Summary, as SpottedKitty said, there are 3 (4) parameters which define how long a render will run.

    • Max Samples - How many iterations the render runs before it stops
    • Max Time - How many seconds the render will process before it stops. This is approximate as it will always finish the current rendering pass before stopping.
    • Convergence - A quality setting based on a sampling of the pixels in your image. Basically, a pixel is converged when it doesn't change from one iteration to the next.
      • Quality - Controls how large the sampling will be. The higher the quality, the more pixels checked for convergence. Sampling for convergence takes time each time the rendering canvas is written; so higher values can increase rendering times.

    On the first, two, you can also edit the parameter to turn limits off and set the values as high as you want. Which works fine if you're confident in your quality settings for convergence.

    On the topic of spectral rendering, the video explains this. It basically remaps the color space of the image using some mathematical algorithms. By default, Iray gives equal weight to all colors of the spectrum. With spectral rendering turned on, it will change the spread, emphasizing certain parts of the spectrum and minimizing others. It will almost always change the time it takes to render and will effect the overall look of the image. In my opinion, it's more useful if you're trying to map the colors of your rendered image with a background and the spectral balance of your render isn't matching the background.

    The best way to see the effect is to load the Daz Material Ball scene and do some test renders with various settings. Look at the spectrum decals on the floor of the image to see how spectral image changes the color weighting.

  • StratDragonStratDragon Posts: 2,838

    Great info! Thanks everyone!

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