Another comparison test: The exact same scene rendered first in Terragen 1.8.76.0 and then in the current release, Terragen 1.9.03.1. The scene was saved from Terragen 1.8.76.0 and re opened in Terragen 1.9.03.1 so although the smoothing option was there it had no effect. Also note that the "white blur" grass clump added to show the position of the single object in the first render has moved back to its origin in the second render.
To Harvey and BigBen: I made the tree tests as they are our "Life Blood" so to speak. If the testers had been only using Xfrog trees or models of that sort of complexity its easy to see how this was missed. With several populations in a large scale environment any lighting issues very quickly become hidden.
Its a sunny day here in Somerset so have a Happy Tuesday Y'all
Richard