So Im trying to build a forest with Megaplants and everytime I swtich from Lit to Path Tracing the meshes switch to what seems like a fallback mesh - few splotchy, detached triangles. I looked around forums and tried couple of things that keep appearing over and over, such as
but none of them seem to solve it. Hardware ray tracing is turned on in Project Settings, and when I try to force fallback mesh to be the high poly version (Keep Percent Triangles = 100%), the UE crashes every time.
Whole another issue is getting them work with PCG, as it seems like the PCG graph doesnt allow for skeletal meshes? It only has a static mesh spawner.
Checking around the community, there are ways to handle both issues, let’s just go in order first:
The interaction between Megaplants and Path Tracing is mostly due to Nanite, as the tracing can’t use virtual geo directly, it needs a fallback mesh. The detached splotchy triangles you are seeing are the result of this clash.
As for the commands you were testing, r.RayTracing.Nanite.Mode 1 is a good approach, forcing RT to use the Nanite geo. But it will only work if the static meshes have “Support Ray Tracing” enabled. Open each asset on the content browser, check under Details > Ray Tracing, and tick the box below:
On the other hand, r.Nanite.ProxyRenderMode 0 goes against this, as it will enforce the fallback mesh on scene. I would set it back to 1, once the changes of the previous step are complete. If the issue persists after that, I would consider disabling Nanite from the Megaplant assets, as a workaround.
For the other issue, Megaplant assets should be static meshes with WPO wind motion. If this is not the case for your assets, then you can test by replacing Static Mesh Spawner by either Spawn Actor (use a blueprint actor that contains your skeletal mesh), or Instanced Skinned Mesh (plug your skeletal mesh directly).
