Questions about collision and LODs for a low poly mesh.

Hello, my mesh is a large prop (a round medieval tower) that’s very low poly (~4k tris). If I try to reduce polys the textures break and the tower looks deformed. I will have at least 20 other towerse in the scene (very far away from each other but visible at the same time), plus other objects. Should I bother making custom LODs or just leave it at 4k?

Regarding collision, Should I just use complex as simple (i.e. use the same mesh for collision)? I guess I could slightly improve poly count for a custom UCX but it would also be more imprecise. Or should I try to use primitives inside UE?

What should I do?

Hello! If you’re not using nanite then it’s pretty much always beneficial to have LODs for a real-time environment, especially in a case like this where you have 20 visible 4k meshes far away that would take 80k of your poly budget for the scene and potentially give you some slight overdraw issues. I wouldn’t bother with custom LODs these days unless I’m trying to retain something like a vertex-painted surface, but I would definitely let Unreal generate some LODs and fiddle with the distance and reduction parameters to get the result I’m after if the defaults are crushing the mesh.

As for collision, a similar mindset applies - you want to keep the meshes that will be used for any type of interaction querying as lightweight as possible. Pretty much the only time you’d want to use complex as simple would be if you’re having visible culling issues due to something like a hole in the mesh that allows the player to see the other side, or if you really need a super tight-fitting collision for an interactable surface. For the most part you have all the tools you need in Unreal these days, so can use the best primitives for the job or let Unreal generate the collision for you.

This stuff can sometimes feel a bit like overkill with today’s hardware, but in the end every little bit of resources you free up opens up more resources for something else - that’s the fundamental beauty of real-time rendering. :smiley: