I am a 1 man team, so modeling isnt my main thing, but I do have an artistic left half. So, I need to make some tree models for my world and am not sure how I should create them. For example, I am wondering if I should break up the tree into 2 seperate models: the solid stalk center as one, then all the leave folliage quads as another. Why? I am thinking that the stalk/trunk doesnt need alpha rendering so all models if this type get rendered in the non-alpha batches and can save some alpha testing. The leave/folliage model *is* rendered with alpha and will be batched at the end with all other alpha batches. Another concern is with shadow mapping trees. I am considering, using a low LOD billboard of the tree also as the shadow map for projection, instead of going through the model polys for possible speed reasons, if possible. Well, this is where I am at. I dont know if I should be worried about the alpha rendering or not. Im curious to know how you guys (or your artists) do things. :o/ - john

The best way to find out what to do, is to test it :) If you have an engine of some sort where you can test these in, great.
Start by making one tree model with the trunk seperate from the alpha texture, then have another model that just uses one texture.

Place 50 or so of these objects in your game (first one type then the next) and compare the FPS, or load time, or whatever. That's a good way to benchmark.

I think you shouldn't break up the model.
Use masking. I mean all black(0,0,0, green 0,255,0 or red 255,0,0 for example) pixels of texture are transparent.
I don't know is your engine support masking, but if so, you can make a whole mesh.

I hope you'll understand :)