I'm currently experimenting with babylon.js and have some questions about optimizing shadows. I'm playing with a large forest scene, with trees and rocks. I'd like the trees to cast shadows on to the rocks and the ground. Here's an example of part of my scene:     It works, but sometimes renders slowly (low FPS). To try to improve the situation, I've added fake (rendered) shadows to the ground texture so I could get away with having fewer trees explicitly cast shadows. I also reduced the resolu