Some machines render lights dim.

[Dubbie99]

I have a scene with a Vray directional light (0.8 directional value) and some objects.
On about 1/2 the renderfarm machines, the Vray light renders at about 25% the brightness that it should. It is always the same machines that render the light dim. The machine hardware, OS, max version, Vray version, units setup are all identical.

It is not a gamma issue because the dome light in the scene renders the same on all machines.

Switching to scanline and back to vray in order to refresh the vray settings has no effect.

[Dubbie99]

Further to this issue. Here is a simplified scene with 1 object and 1 light.
This scene renders quite different on two identical machines.

[Dubbie99]

And the scene:
http://www.filamentvfx.co.nz/dump/Troubleshooting2.zip

[Dubbie99]

Ok, I think I have finally figured out WHY this is happening. I'm not sure yet how to fix it however.

The directional parameter is changing on some boxes! If I save a file from my workstation with a directional param set to 0.5, when I open it on the renderbox, it has magically changed to 0.25
Saving on the renderbox and re-opening on the workstation, the value has halved again!

Setting keyframes makes no difference.

I have doublechecked the units and they are indistinguishable.

R

[Dubbie99]

I'm kind of working around this for now with a pre-render script that forces the light back to the correct value. Any info on this issue would be very welcome.

R

[Dubbie99]

[edit] Has anyone else encountered this problem?

it's driving me nuts.

[MoonDoggie]

Absolutely no idea, try deleting the problematic lights and recreating them. (Though I'm sure you've tried this already)

I would consider completely fresh installing VRay on the problematic machines. (Last resort, but worth a shot).

[Dubbie99]

Tried both of those suggestions!