I think that if a feature is added to detect the surface normals (single-sided) of the imported 3d object, then it could be used as the 'reference' for planting the population onto. Hope this can be added for the final build...
I am currently building a fantasy-based sky-city in Maya as a one-year research-based project, which along the way extended to include Terragen 2 (TG2) in an integration attempt. So far, I have successfully integrated camera and the terrain mesh (from Maya) and matched them up pixel-precise in TG2. I used TG2 to build the environment and did some prelighting with the imported mesh. Apart from generating the final rendered environment frame, I also output 6-cubemaps, processsed them into a HDRI Light Probe and brought it back into Maya as a indirect illumination source. I posted this question earlier as I thought of stacking a Population (of trees) onto the sky-city's terrain itself, which I already brought into TG2.
