Negative Light Effects

[Joelaff]

Sure would be great to be able to use negative lights to darken voxels. I didn't seem to be able to get that to work. Useful for fixing issues, and special effects, etc.

Thanks.

[Svetlin.Nikolov]

Ohhhh, that sounds naughty

Honestly, never tried it, and I'm pretty sure there's more than one place where the code is not prepared for that. Gotta run a pass to evaluate what's actually needed and how it works with other V-Ray primitives...

[Joelaff]

Yeah, negative lights are a fun trick. We used to use them back before GI existed. You'd run negative tube lights at wall intersections, and point lights in corners, etc.. Poor man's VRayDirt or GI.

In my case I have a vehicle on top of some clouds that I need to brighten with an ambient light, but I really want a dark area underneath. Right now I am subtracting the ambient light out in post, but would be nicer in the render, and avoid some roto.