VRAY7 GPU // Directional light set at 1 and texture map in slot

[nicolas_fuminier]

Hi there,

As far as I understand the issue, on a simple Vray square light, light multiplier value has no control over the light intensity if :
- Directional light is set at 1
- Any map pluged in the slot map of the light.
Even at a multiplier value of zero, the light still emit full blast.
The issue does not happen if the directionality is 0,998 (sadly i want a video projector type of light so I really need directionnality at 1)
No matter CUDA or RTX.
The issue does not exist in Vray CPU

Windows 10
Dual 3090 SLI
Max 2025.3 27.3.0.30874
Vray 7.00.05.32856
Nvidia Driver 572.16

Thanks,
Nicolas

[hermit.crab]

It's just a V-Ray GPU thing (sorry, didn't see that we are in this section), which is already logged (internal tracker id: VGPU-5095), but forgotten. I'll revive it. Otherwise, you can workaround it by controlling the intensity through the texture Multipliers (VRayBitmap > Processing > Overall multiplier).

[hermit.crab]

As far as I understand the issue, on a simple Vray square light, light multiplier value has no control over the light intensity if :
- Directional light is set at 1
- Any map pluged in the slot map of the light.
Even at a multiplier value of zero, the light still emit full blast.

Doesn't happen on a fresh scene. The light multiplier affects the intensity as expected. It must be something specific. Could you attach/send the scene?

[nicolas_fuminier]

hermit.crab Thanks for the follow up.

This is weird indeed,
I've just redo the test on a fresh scene and it happen again. Maybe something on my side then.
https://www.swisstransfer.com/d/15b0...d-42a5efde0d3d

I've just switched to RTX, made a few ajustement on the light, load a VrayBitmap and that's basicaly it.
I'll try to redo it again with the less adjustements possible.




Nicolas

[nicolas_fuminier]

I've redo the test with the minimal amount of step to avoid any bad move.
Issue is still there.

- Open a new scene
- Create a plane with a white Vray texture acting as a screenplay
- Create a square Vraylight. Put any texture in the map slot. Set the directionnality to 1. Set the intensity to 0.
Everything else is vanilla (I just use Linear workflow, not the OCIO one but I don't think that's important).
Light still emit.

[hermit.crab]

It's just a V-Ray GPU thing (sorry, didn't see that we are in this section), which is already logged (internal tracker id: VGPU-5095), but forgotten. I'll revive it. Otherwise, you can workaround it by controlling the intensity through the texture Multipliers (VRayBitmap > Processing > Overall multiplier).

[nicolas_fuminier]

Thanks for the summary and the work around,
We used to fake the intensity with the output amount of the map, but it might be cleaner with the overall mult.
Glad to see it might fixed. Sometime it's easier to go by the light intensity (Light lister for example) rather than a value in the map.

Best,
Nicolas