Extremely poor Lumen performance with trees. Even billboard trees

I set the trees to the lowest billboard LOD and it barely helps the framerate at all. The performance gets worse with the scale of the trees, and LumenScreenProbeGather seems to be the culprit.

Does anyone know why this is happening?

Be sure to turn Use Hardware Raytracing OFF.

With the scale of the trees? That’s quite interesting, I’ve never seen performance behavior like that before. The ScreenProbeGather is lumen’s actual tracing of rays, whose costs should generally scale with resolution. It’s designed to throttle ray-tracing accuracy rather than hamper performance, and operating that poorly on such an environment is very unusual.

Candidly, I haven’t experimented with billboards and lumen (the newest version of Nanite supports masked materials and WPO, so there hasn’t been much need for me). But if this is still an issue, is there any way you could share the lumen scene visualization? That might help diagnose the unusual behavior, and if you could use profileGPU to narrow down the exact sub-operation resulting in the behavior (is it the cost of tracing rays, or some acceleration structure or filtering cost?) that might help you understand your behavior better. Best of luck.

Those warnings you are getting are causing the pipelines to explode(texture streaming). Any kind of warning means something like nanite or lumen can’t operate at acceptable computing rate. Same thing happens with Vram limit.

Same kind of performance explosion I had like in your video.