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Iray Color and Exposure Discrepancy Between Sessions on the Same Scene (RTX 50xx, Daz Beta Premiere)

Little MelonLittle Melon Posts: 11
edited May 26 in Technical Help (nuts n bolts)

Hi everyone,

I’m running into a deeply frustrating issue with Iray rendering inconsistent exposure and skin tones between different rendering sessions of the exact same scene file.

I am currently rendering a series of images for a project, I am using the exact same scene save file, with absolutely zero changes made to the lighting, environment, cameras, or character materials. However, when I loaded the file to render the next batch of images on a different day, the entire new batch came out uniformly darker and more saturated. You can see this in the comparison image attached below, the right side is noticeably darker, especially in the skin subsurface scattering and shadows.

I have already verified that the camera Headlamp is explicitly set to Never, so there is no accidental camera flashlight interference here. Since I am using a newer GPU, I am forced to run Daz Studio Beta Premiere, as the stable release does not yet support my hardware architecture.

My Setup:

  • OS: Windows 11

  • GPU: NVIDIA RTX 5060 TI 16GB (Blackwell Architecture)

  • Software: Daz Studio Beta Premiere 

  • Drivers: NVIDIA Drivers (Studio)

The Problem: The first set of renders looks perfectly fine and bright, the second batch, rendered a day later after a fresh system boot, is uniformly underexposed. The shadows under the clothes and around the neck are much deeper, and the skin loses its subsurface luminosity. It behaves as if the Tone Mapping parameters like ISO or F-Stop completely ignored the saved file settings upon loading the new session, or perhaps Iray is compiling the shaders differently on this GPU architecture between system boots.

How to solve or prevent this? If anyone else using the 50-series GPUs on the Beta version has encountered this silent shift in exposure, how did you fix it? Is there a way to lock Iray's deterministic rendering so that a saved file actually renders identically every single time?

Any advice on Tone Mapping workarounds, VRAM texture compression bugs specific to Blackwell, or forcing consistency in the Beta Premiere build would be highly appreciated.

Thanks in advance! <3

 

Post edited by Little Melon on

Comments

  • Little MelonLittle Melon Posts: 11
    edited May 26

    Just to add some quick context, only the whole character's skin is changing its color. The clothing, hair, and background look exactly the same.

    Post edited by Little Melon on
  • Little MelonLittle Melon Posts: 11

    Restarting the computer helped, but the photos where the legs were rendered on a “clean” system (nothing had been running beforehand) still have a different shade.

     

    I have absolutely no idea what causes this.

  • Little MelonLittle Melon Posts: 11
    edited May 26

    After restarting, I was only able to render one photo; after that, all the subsequent ones are dark again

    Post edited by Little Melon on
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