Thanks, guys.
Dhavalminstry - After I make the changes suggested here I'm going to run a whole series of renders from this scene. You'll like one from in front of the mosque - there's really pretty tile work on the front around the doors.
Calico - If you're talking about Ben's long grass, here's what ya do. Add a single object of the long_grass.tgo. Right-click on it in the node view and select 'Internal Network'. You should see a rather complicated network - 2 main shaders, each with 2 additional surface layers and their fractal breakup nodes, all feeding into a mixer, which is controlled by yet another surface layer and fractal. As I mentioned elsewhere, I believe the intent was to provide a means of changing color with elevation or distance or whatever. It doesn't work, though, becuase the internal network has no knowledge of external terrain. (I think.) The thing to do is strip this network way down, say to a single main shader with a couple of highlight child layers, then connect this smaller network to the 'Surface Shader' input of the internal network. Then you can change the color of the population by changing the color of the new single main layer, with some scattering of the highlight colors as you see fit. Once you've made the desired modifications, right-click the object in the node view and save the object file. It'll retain all the changes you've made (so you may want to save it under another name).
