To make a forest for a project I'm working on I am using simplified cutout trees made from three intersecting tree image planes with transparency. these have the three planes spaced 60 degrees apart sharing a vertical central axis. I'm using Cycles.
The issue is that when rendered, the planes cast shadows on the other planes of the same tree, which pretty much ruins the illusion. The shadows cast on the ground are OK, just not the ones falling on the tree itself cast by other parts of the same tree.
I tried using an emission shader, and get pretty good results but only so long as the tree isn't being shadowed by something else (in that case, they seem to glow like they are radioactive).
Is there a way to configure the material nodes for cycles such that the object doesn't cast shadows on itself, but allows other objects to cast shadows on it, and allows it to cast shadows on other objects? Any other approach to accomplish this than the material configuration?