Why is my translucent material causing overdraw and poor performance in complex scenes in Unreal Engine 5?

Development Rendering
1

Hi everyone,
I’m currently working on a game in Unreal Engine 5 that involves complex indoor environments with dynamic lighting and several translucent materials (like glass, force fields, and holograms). While everything looks good visually, I’m noticing significant performance drops, especially when multiple translucent objects are on screen.

I’ve checked in the GPU profiler and noticed a lot of overdraw in areas with multiple overlapping translucent meshes. I’ve already tried switching the materials to different blend modes (like Masked), but in some cases I lose visual fidelity that’s important to the scene. I’m also avoiding using too many dynamic lights overlapping with translucent materials, but it doesn’t fully solve the problem.

Is there a best practice in UE5 for optimizing translucent materials, or should I consider using alternative rendering methods like custom depth or render targets? Are there any features in Nanite or Lumen that can help in this case, or are they irrelevant for translucent rendering?

Any advice, resources, or workflow suggestions would be greatly appreciated. Thanks in advance!

2

It is really simple, overdraw means that pixels are drawn multiple times. And that is because material is translucent, does not hide any pixels behind it.

So non translucent drawn behind single layer/surface of translucent material is fine. However multiple translucent surfaces one behind another is quite bad. And you have some render mode (F3 in editor i think) to see that in view.

Best optimization for it is level layout and not abusing translucent surfaces.

TL/DR:
It is NUMBER of translucent surfaces one behind another that matters most.