Hello,
I’m still experiencing a lot of issues with Lumen being very unstable, especially with trees that partially block the player’s view.
Whether I disable HZB or not doesn’t make any difference. I’ve tested various Lumen-related console commands, but nothing seems to help. It really feels like Lumen is only good at rendering empty terrains with no occlusion, which is quite frustrating.
Here’s the YouTube link in 4K. With the encoding and the lower resolution of the forum’s video player, the issue may not be entirely visible: https://www.youtube.com/watch?v=0MQ5c_tU1JY
Of course, removing the tree entirely from Lumen’s calculations fixes the issue, but it also completely disconnects the tree from the scene. And if we have to do that for every object that occludes the view like a tree with a building behind it in the distance then Lumen’s usefulness becomes seriously limited, even pointless, especially compared to older systems like RTXGI that used grid-based probes.
Disabling all Lumen downsampling also fixes the issue, but it makes Lumen extremely resource-intensive taking over 30ms on its own. At that point, it’s heavier, less efficient, and offers lower fidelity than Nvidia’s ReSTIR GI.
It’s really unfortunate that Lumen doesn’t address these issues. This problem seems to have been present from the beginning likely inherent to its calculation method leaving no choice but to seek an alternative, more efficient external GI solution that doesn’t suffer from occlusion problems, handles foliage better, isn’t so resource-heavy, and doesn’t rely on massive downsampling and heavy temporal techniques. It’s a real shame and far from Epic’s initial promise of “We make the tools, you make the game,” especially when we end up having to use third-party solutions or downgrade visuals.
In this second video, screen tracing is completely disabled, downsampling is set to 16, TSR is pushed to its maximum with a 200% history, all running on Lumen hardware at native 4K. And honestly, the results are really not good.