Assist with Env Fog or Scatter Fog

[Zach Gray]

We are working on a short, and are struggling to get the correct fog look in a scene. The scene requires a bright spotlight, and we want the fog to be dense in the cone of the light, but to be sparse in the rest of the scene. If there were a multiplier for the light effect on the fog, that would be great.

We understand the envFog workflow and have used it successfully in other scenes. Build fog, hook it to env tex, place an invisible bounding cube in the set. Override shape lights, place lights in set.

What's the right way to do this? Two lights, one on the subject, with a duplicate very bright light linking to the fog set? Should we use scatter fog? (Unclear on this workflow)

Here is an illustration of what we would like it to look like.



Here is a link to the scene/textures. (It has no fog in it now. Stripped it out because it was looking so flat.)
http://southernlabs.net/downloads/vray/

FogHelp.zip 278MB

[Zach Gray]

We tested with the dual light/light link approach, and that seems to work, but want to confirm that it's the correct approach.

[Zach Gray]

I wanted to follow up with the result.



There is another issue. The rectLight (lower left) is showing up, but I've confirmed that it's invisible! Is there a way to hide it from the render? Or is it because of shape lights and fog?

[vlado]

Is the rectangle light supposed to affect that part of the fog? Is there a texture map attached to the light color?

Best regards,
Vlado

[Zach Gray]

No, we specified shape lights, and those little rectLights are not in the env fog set. The light color is solid.

[vlado]

Ok; do you think you can get me just that part of the scene?

Best regards,
Vlado

[Zach Gray]

Vlado,

While we were preparing to send the scene, we found the solution. The artifact is caused by an invisible rect light with the exact position as another rect light. Wherever the planes of those lights overlap (in mathematically identical common plane) you see the artifact. The error was caused by the lighter duplicating the light, changing settings, and light linking.

The workaround is to move the duplicated light by a very small amount so it's not coplanar.

Thanks.