View Full Version : MR fog visible in refractions?

01 January 2006, 01:01 AM
Hi all, I have a sphere with a blinn on it, Completely reflective. In Maya Software i added an environment fog and rendered the sphere. Fine, looks good. I added refractions to the sphere, and the fog doesnt show through. Under the fog attributes i set it to be visible in reflections and refractions. Fine, looks good again. I switched over to mental ray and now the fog doesnt show up in the refractions or reflections. Any ideas? Help would be greatly appreciated. Thanks.

01 January 2006, 06:56 PM
has no one encountered this before? i cant be the only one . . . :-(

01 January 2006, 07:24 PM
im pretty sure standard environment fog is a post process in maya - mental ray may not handle it correctly.

instead you could try using a large fluids container - set it to non-dynamic and set a uniform gradient density going away from the camera.

01 January 2006, 08:13 PM
cool chronic, thanks for the info. I actually did try that, but im using an ambient occlusion shader on my surfaces, and with the fluids, the AO shader sees the container as an object, so whenever another object is inside it, it doesnt recieve any AO. . . . any ideas? Im stumped . . . bah!

01 January 2006, 09:13 PM
you could do it in 2 passes -

1 scene with the fog/fluids and all your object with a surface shader with matte opacity 0.0 (to be transparent in alpha)

2 your regular scene without the fog and any shaders you want

you can then layer the fog over your regular shaded objects (and adjust it too)

btw: in real life fog in the environment tends to reduce contrast, saturation and detail with distance - check out some photos of cityscapes with fog.

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01 January 2006, 09:13 PM
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