what is better? Using an alpha image or modeling a leaf, flower, or other plant material. I've read a few places that using a modeled leaf has a faster render time. You also get more control and can add more variety if you model it yourself. But what do you guys think? This is for photorealistic renders.
For a close-up I would certainly model and texture the leaves, however, at a distance a simple alpha texture could get just as realistic of a result with much less computing power. For example if you are taking a closeup of some foliage and then zooming/focusing on a subject, modelling the extra detail would be worth the extra effort/render time. However if you just want some realistic shrubs/trees in the background, textures are the way to go. And if it is only for a very distant scene or the background is blurred, having textures for entire sections of foliage might help even more.
Basically, unless you can see the difference, there is no need for the extra polys in your scene.