Grass Performance With Dynamic Light and What Is PrePass DDM?

[anonymous_user_b537cab31 (anonymous_user_b537cab3)]

I have a relatively simple scene and lighting setup.
However my GPU is taking a massive dip when using Megascans grass, and with that I mean that ShadowDepths is taking up 29.84MS and PrePass DDM is taking up 23,60MS.
But when i get too close to the grass it takes, ShadowDepths can take up a massive 46,24MS!!!

But I have no idea what PrePass DDM is, nor could i find anything about it to help me out.

To give more context;
I have a 8kmx8km landscape scene, with a landscape tesselated material. Tesselation multiplier is set to 1.
The scene has Exp Height fog, Atmos fog and a simple PPV with bloom.
My directional light is dynamic and my skylight too.

My shadow distance of the directional light is set to 600000 units.

Also I have Distance Field Shadows etc. enabled.

Without grass my ShadowDepths is taking up 13,95MS and PrePass DDM only 3,56

Is grass with realtime lighting so heavy, or am i doing something wrong?
Would setting my directional light to stationar solve the problem, or would it really need to be static?

Here are some screenshots of my scene;

[Chosker]

what’s your grass cull distance? you might be rendering too much of it.

also try to limit your grass mesh shadow casting to only the lower LODs, i.e. in the mesh asset itself take the highest LOD (maybe also the next one) and under Sections disable Cast Shadow

[anonymous_user_b537cab31 (anonymous_user_b537cab3)]

@Chosker

what’s your grass cull distance? you might be rendering too much of it.

also try to limit your grass mesh shadow casting to only the lower LODs, i.e. in the mesh asset itself take the highest LOD (maybe also the next one) and under Sections disable Cast Shadow

So you mean to disable the shadow casting on the LODs that are rendered the most far away with the camera, so let’s say LOD5?

Also I painted the Grass and didn’t use the “Landscape Grass Type”, so culling distance min/max is set to 0.

Is it better to use the “Landscape Grass Type” for performance reasons or do i just have the wrong settings?

[Chosker]

@anonymous_user_b537cab31

So you mean to disable the shadow casting on the LODs that are rendered the most far away with the camera, so let’s say LOD5?

yes that’s what I mean

@anonymous_user_b537cab31

Also I painted the Grass and didn’t use the “Landscape Grass Type”, so culling distance min/max is set to 0.

Is it better to use the “Landscape Grass Type” for performance reasons or do i just have the wrong settings?

landscape grass is more performant so it’s recommended for small meshes that require no collision (landscape grass doesn’t allow collision). but in any case you should set up culling for your meshes either if they are landscape grass or foliage.

[anonymous_user_b537cab31 (anonymous_user_b537cab3)]

Thanks I’ll take a look at it and see what works best.