strange env fog problem

[super gnu]

Hi.. im trying to do a very simple scene. spotlight shining on a red ball in the corner of a room (dont ask). ive added a vray enviromnment fog to a gizmo round the scene, and linked it to that light.

when i render certain buckets ( along the edges of the light volume) decide not to render the env. fog at all.

See attached image to see the problem. now there is a section in the notes on spot3d that says you may get harsh edges to a volume if the noise threshold in the fog is too high.. ive tried changing this repeatedly, all the way down to 0.0000001 and it doesnt make a pixel's worth of difference.

im using max 2011, vray 2.00.20, and also, im NOT using distributed rendering.

thanks, Robin.

[vlado]

You will need more subdivs for the fog, or if you use the adaptive DMC image sampler, you can increase the min. subdivs. The problem happens because in those areas none of the initial samples hits any part of the light cone, so V-Ray does not think it's necessary to use more samples.

Best regards,
Vlado

[super gnu]

thanks that nailed it.