Grass and performace

Hello Unreal community,

I am working with UE4 for a few months and I love it, however I have one very important question. I did a landscape about 4x4 km, and did in speedtree simple model of leaves so it looks like a grass. I used a foliage tool to paint my landscape with that test grass, however when I tried to build my scene, engine said “Large actor receives a pre-shadow and will cause an extreme performance hit”. I found, that this issue can be solved by disabling dynamic shadows for the grass, but in that case grass will be with static shadows? What is the best solution for grass and also I will be placing a lot of grass on my landscape, will that hit performance? I need animated grass not only static but with bending leaves, please share your experience.

With all respect

Keep an eye on this thread Custom Foliage Lighting Model

Place a lightmass importance volume into your level (this will reduce the rebuild time). When you want to have a good performance, you will have to cull your grass with the foliage tool + the meshes have to be very low poly (just planes). For more complex meshes you should also use LOD’s :slight_smile:

Thank you guys for your replies. But what about bending grass? Should my plane be divided into a few parts to bend or I can do some manipulations with grass texture to simulate wind? I saw somewhere, that it is possible to make some things with texture to make it like on a wind

wind: (basic)
bending: https://forums.unrealengine/showthread.php?3268-Nature-Environment-in-UE4 (here you can find some good wind and bending grass setups) :slight_smile: