SM with lots of poly vs. lots of SM and less poly

Hello everyone,

I’m trying to add some pebbles all over an area of my map, and for that I have plenty of little pebbles meshes.

But I’m wondering, as I’m going to use the foliage tool to instance them, should I regroup all of these pebbles into one big static mesh and place that static mesh on my map, or should I have one static mesh per pebble and paint them all over my map with the foliage tool?
What way is the most efficient?


I would use low poly pebbles which will be placed with the foliage tool -> the foliage tool renders them in clusters + culling is easier + it’s more flexible


What is the advantage of rendering it in clusters?

Also I just tried to render a mesh with the foliage tool and I notice the LOD doesn’t apply… It’s always rendering the LOD0 even when I’m far away from it.
LOD doesn’t work with the foliage tool?


It gives you a better performance because it renders those clusters in a single draw call.

So I think the problem comes from the fact that I’m using different UV between LOD 0 and 1…

For my LOD, I firstly import my high poly mesh, then open it in the SM Editor in UE4, and click Import LOD Level 1. But they have different wrapping.
Is there a way to have both LOD0 and LOD1 in a single fbx file? In the import option there is a “Import mesh LODs” but I don’t know how to use it and I can’t find any docs about it… :frowning:

Just export the different LOD stages as a separate fbx file: and then impor them over the “impoet mesh lods” button (in the video I show the entire process)

Well, that’s what I’m actually doing for my different LOD. But as Tim Hobson said here :

My two LOD meshes doesn’t have the same Unwrapping because I’m using the Decimate tool in Blender to create a low poly one and it generates different UVs.
How can I have both meshes have the same UVs?

In 3Ds Max there is a way to save the UV unwrap as a file and import that to apply it to another mesh.

I found a video that explains how to do this in Blender. I don’t use Blender so this version may be different or have outdated features.

Hopefully this helps!


Decimate tool respects UVs to the best of its abilities. It may look different, and end up losing some of the texture detail, but for a LOD mesh, it should be acceptable. Light and shadowmaps in this case shouldn’t matter as much, as UVs are still in the general vicinity, shading errors should be minor.