We have a project that we upgraded from 5.4.4 to 5.6.1
It ran at 60fps originally and in the upgrade to 5.6 we got a lot more quality from lumen and want to use megalights. the project still runs at 60fps but over time more and more vram is used as you fly around the scene. eventually it exhausts all memory and the frame rate tanks to 10fps or less.
Disabling nanite solves it. Disabling raytracing solves it. They cant be enabled together.
Toggling virtual shadow maps in console command resets memory usage, so you can toggle it off and memory usage resets and then begins to climb again. you can toggle it back on and memory usage resets and begins to climb again as you explore.
Turning all levels off in the level outliner resets memory usage as well in the same manner as above.
Deleting all lights doesn’t stop the problem from happening.
Looking at the Render Resource Viewer and comparing it to 5.4.4, two entries are very different.
NaniteRayTracing.IndexBuffer and NaniteRayTracing.VertexBuffer 256mb and 192mb in size. in 5.4.4 there are just 2 of these in the viewer. in 5.6.1 there is about 5 at the start and then they multiply into 100+ and eat up as much memory as possible.
Any ideas what is happening here?