Fog problem

[YoyoBoy]

I have some IES lights attached to a vehicle and I have assigned VRayEnvironmentFog to them. After lots of frustration, I discovered that the fog isn't working because the vehicle is -50 meters down. When I move it up to 0 they work just fine. Is this normal? I'm on VRay 2.4.

Thanks.

[tashko.zashev]

Hi,

Is it possible to attach a scene for this to check what is wrong?

[alexyork]

I found this as well - I've only used vrayfog once before but I remember having problems if the ground plane in your model is not at Z=0. This was the case for me because I was working on a huge terrain model that went from -100m to +100m with 0m being ground level, but I needed fog to "start" at -100m in the valley.

[YoyoBoy]

Yes, my scene is a large environment as well.

[tashko.zashev]

Actually this has been fixed in the 2.4 nightly builds and latest official 3.0 builds.
V-Ray Environment Fog allows negative values for high there.

[alexyork]

Great news! I might try to employ this in future images.

[YoyoBoy]

Can I get access to the nightlies? The more I experiment with this problem the less sense it makes. It seems to fail as soon I do nothing more than merge into the scene the house-sized dumptruck that the lights are supposed to be attached to. Not sure why it seemed related to the elevations of things yesterday. In my testing this evening that is irrelevant.

[YoyoBoy]

Ok, so I just did more testing and it seems like the lights get "poisoned" when I move them near to where they are supposed to go on the truck:

1) I have two lights working fine, casting VRayFog beams and illuminating a Greebled plane object beneath them.
2) I import the truck and they are both still working fine, even after moving one of them next to the wheel of the truck.
3) I move that light NEAR to the light fixture where it is supposed to go on the truck and the beam disappears, but I see a splash of light from it on the ground -which is weird because I have no ground object in that part of the scene. Actually, the illuminated "ground" looks rather foggy.
4) I move the light back to where it was, next to the other light and I see that it still isn't working properly, whereas the other one that I didn't move is working just fine.

I realize I'm just a poor boy using measly old version 2.4, but I really need to get this problem fixed. Can I send my test file to you?

Thanks.

[YoyoBoy]

Ugh. Nevermind. I'm an idiot. I figured out the "problem." Fog height.