The real-time foliage rendering technology
SpeedTreeRT has been integrated with Epic Games' Unreal Engine 3. SpeedTreeRT delivers low-polygon, highly realistic trees and plants, with adjustable wind effects, seamless LOD transitions, and an included library of hundreds of tree models from more than 100 core species. SpeedTreeRT includes SpeedTreeCAD, a Windows application used to create and edit animated trees in real-time. Check these amazing
screenshots to see for yourself what I'm talking about.