I'm trying to render a scene utilizing X-Frog plants, which render fine close to the camera, but turn black in the distance. I'm using the same mental ray (v188.8.131.52) settings and lighting set up as the farmhouse road tutorial. In the sample image attached, the palo verde trees look perfect close to the camera, but in the distance the trees should be just as bright green as the foreground. This is happening on all my x-frog plants, I just dropped down to one species to try and isolate the problem.
A second question on materials. Right now the tree material consists of three standard materials grouped under the forest multi/sub materials. When I switch the standard materials to Arch and Design, the net effect makes the plants render even darker. If I should be using arch and design for the sub materials, how can I brighten up the trees?
Any help would be appreciated. I'm using forest pro 5.20, Win 7 x64, 3ds Max 2017 Service pack 3 with 128 gb of ram and an Nvidea quadro with 4gb of ddr4 vram.