Well, I tried something that so far has been a real success. I did a viewshed analysis in POV-Ray. Nothing significant in that analysis– it’s just a topography based analysis, just like one might do in GRASS or ArcGIS. But what is interesting, is now I can add buildings (also not hard in a GIS) and trees (which can be quite hard to add). Suddenly the viewshed including trees need not be a solid wall of trees, but something partially penetrable and complex. I’ll do this in part with some new lidar data I have… and update here. In the next couple days, I’ll post the code and results I have so far. The code is very simple and not terribly flexible yet– just a test of concept, but we’ll see where we can go with this.