Need ideas for lots of trees

[mikeh]

what about a scanline/mental ray billboard 'tree' pass then comp'd in post?

we are having a similar headache with marram grass on a golfcourse and needing to render for HD too! trying to billboard some of the clumped grasses in the far distance, then up near the camera replace with geometry.

looked a vue, but the scaling probs put us off..

Forest works with Mental ray and vray....but it is still billboards.
mh

[charleyc]

I actually would use PFlow to billboard your plants (it gives you quite a few options for placement). It also allows you to easily increase or decrease the number of trees as needed.

For the GI and shadows I would use the outlined mesh method described above. A quick way to create the outline is to use the alpha on a plane. Use subdivide to get a crazy dense mesh, then Displace out the alpha. You can then easily select the background faces and delete them. This allows you to use the Border to Create Shape.

In PFlow, set Event 1 to place your trees where you want and use Shape Facing to align them to camera (use the Parallel function to keep the from tilting up). Set this event to not cast shadows, and exclude it from GI.

for Event 2, create and Instance of Event 1 with the exception of the shape op, use Shape Instance and use your shadow mesh. Set this to be invisible to camera and not recieve shadows. Also, it is a good idea to use a scale op (rather than the variation parameters of the Shape Ops) so that you get a consistent scaling for each event.