Hi,
We have been experiencing a bug with nanite that happens intermittently. Depending on GPU load, all nanite meshes in the scene will sometimes revert to their fallback mesh (confirmed using Nanite viewmode, everything is black). It seems to be happening more consistently in a packaged build, or during PIE, but not as often when simply flying around in the editor (not in play). This would happen in 5.3 on one of our developer’s machines running an RTX 3090. We have upgraded the project to 5.5, and it is now happening on a machine it did not used to happen on (when the project was 5.3), which has a 4090. The machine has the latest Game-Ready GPU drivers as of March 11, 2025, but the issue was also happening with the latest studio driver.
The project is a VERY performance heavy project, with over 100,000 meshes and 30,000 light components in one scene. Most meshes are nanite-enabled, when possible.
I do recall finding other threads about this issue before, and some folks were suggesting it could specific to certain nvidia 3000/4000 series GPU’s.
I have submitted a bug report for this, titled “Nanite bug (all nanite meshes reverting to fallback mesh)”
@Krzysztof.N would you happen to have any insight into this issue, or have any suggestions to troubleshoot/fix? I think our best option of fixing the issue would probably be to merge scene meshes and material slots to reduce draw calls, although this is not ideal and would be a very lengthy process.