[gadzooks]

Any one have an idea as to why this is happening. The Large trees in the foreground look fine until they pass the roof and then they render funny see image. Also gave material setup
Im still using 1.7

[tom]

Set attenuation to 1 nm or make sure you have pure black pixels in the mask.

[Fernando Tella]

Or mask the layer, not at transmittance.

[gadzooks]

That's it. I owe each of you a beer!