It took a while to figure out the new script in Blender that helps the creation of trees. It is the same script used for the Big Buck Bunny film. Unfortunately there is nit a lot of documentation for it but after fiddle for a while I have worked out what it does so I can better control it. It generates the twigs and leaves off a set of user defined curves, the idea being that this is a happy mix between automatic generation and user control design. These twigs are generated inside of a defined bounding mesh but the trick is that it will extrude twigs towards each verticy in the bounding mesh. So that is how one can exert some control over the generated canopy. I still have trouble getting twigs that don’t do stupid things but it’s getting there.
I also experimented with the leaves as the script allows you to choose an object to become the leaves. I modelled a fern-like leaf which produced a nice result although this tree is very resource heavy.
Wide tree
Wide tree compound leaf