Two minor comments. If you render in Sketch mode, it is possible to check the positions of the plants very quickly. Also, Truespace Version 3 is now widely available and is FREE. It has a very precise 3D coordinate system in it that is very easy to use. You can both build the terrain mesh in it (or export it from Vue or Bryce into Truespace if you have already built the mesh), and then position little cubes or sticks very precisely for the veg positions. Vue imports Truespace files.