Mental Ray not rendering all geometry in distance

[MD]

I have a strange issue in a scene I am working on. I am setting up a background mountain range for an animation, but the larger mountains in the distance are not rendering. They show up in the alpha channel, but not in the diffuse. See the attached images.

 

The mountains are planes with displacement modifiers applied to generate the topography. The peaks in the foreground started as 200'x200' planes then were scaled up. The far range in the background is ~80,000'x12,000'. I wouldn't think physical has an effect, but I'm not sure what else is causing this issue.

 

Viewport:

[ATTACH=CONFIG]45998[/ATTACH]

Alpha:

[ATTACH=CONFIG]45996[/ATTACH]

Diffuse:

[ATTACH=CONFIG]45997[/ATTACH]

[MD]

Another question - is there a limit to the physical size of a max scene? How is this adjusted?

[marius e]

Maybe you have the 'haze' activated in the Daylight system, preventing the far away geometry to be visible?

[maciejwypych]

It looks like it's either clipped (check if you have camera clipping turned on) or the normals are off (go to the advanced options in the material editor and turn off Back Face Culling to make your material visible on both sides of your geometry)

[MD]

Thanks for the tips. I will give these a try tonight.

[MD]

maciej had the answer. I didn't appear to have camera clipping enabled, but changing the far clip distance solved the problem. Thanks for the help!