Rendering foliage such as grass is commonly done using low-poly meshes and alpha-tested materials, which UE4 supports with masked materials.
However, overdraw causes such an enormous performance hit that rendering this kind of foliage is almost impossible without massive FPS drops.
In this example scene, a small patch of grass takes up 8 ms at 1920x1200 on a GTX560Ti.
I don’t think this problem was as significant on a forward rendering path and other modern engines seem to support the same kind of foliage without the same performance hit. I would imagine those engines use some kind of hybrid to solve these issues.
Since foliage is such an essential ingredient for creating all sorts of environments, I was wondering if 1) there exists a solution e.g. by using a different rendering path for foliage and 2) if Epic is interested in solving this (if it can be solved).
I’d also like to hear if other users had similar experiences with foliage.