Below is my metacode for iterating through a grid of images to render the vegetation surface model from povray.  The real code will be implemented in BASH and AWK, although this would be a perfect use of Python, if I knew how to use it… .

PostGIS Tables:

cuy_veg_points:        Load veg points into database and make 2D geometry
cuy_terrain_points:        Load terrain points into database and make 2D geometry
cuy_veg_height:        Use nearest neighbor to calculate tree height into veg point database
e.g. http://www.bostongis.com/?content_name=postgis_nearest_neighbor_generic

cuy_tile_centroids:        Generate tile centroids and load into table– contains coordinates and record area name

Process:

Read cuy_tile_centroids
For each centroid record,
     query view extent for cuy_veg_height
     output temporary tree_coords.inc
     write worldfile for image output from povray
     write povray file with camera position at centroid
     render povray file