Another heads up. A few people were asking if it was possible to use Al Hart's plugin to generate actual 3D trees in addition to the billboards. I'm not sure whether that is possible, because of the Terms of Use of the original tree generator. However there is a little freebie called Arbaro that runs entirely in Java....so it runs from a folder on your desktop (any OS) by double clicking the arbaro.jar file. The results, though, are worthy of anything produced by XFrog or Onyx. It outputs in Pov and Obj formats.
Here is a link to a gallery page showing the results...the download link is near the top of the page.
And attached is a render of a model converted to 3ds, imported into SU (agonisingly slowly) and rendered in VRay. I needed to reverse the normals on the leaves prior to import, for some reason, but the whole model is separate groups, so that was no big deal.
[image: k8Gl_blacktupelo.jpg]