Nanite & Megascan Trees Bugs

Has anybody gotten nanite to work with Megascan trees properly? My trees with nanite, render such that the leafs get chopped into triangles, and the some branches do not render out at all, leaving leaves hanging.
Plus if you walk further away from the trees the LOD 1 &2 fallback triangle counts explode to 200k, vs 20k in LOD 0

Workaround now is to set fallback error rate down to 0 and set fallback triangle percent to reduce the errors of missing mesh.

Tips?

Well Wishes to all who read this.

Seems to be affecting Pivotwind trees but not simple wind trees

I faced the same issue in UE 5.3.2 with Megascan’s trees: tree’s trunk and branches deformed incorrectly, leaves started to look like triangle shapes and small/thin branches completely disappeared.
I found the solution that works for me: in StaticMesh Editor I changed the Fallback Target option from Auto, defaulting to Percent Triangles.

In my case, all Megascan’s trees are back to their original look, the same as they were if Nanite is off. I suppose there is some problem with the Auto parameter for the Fallback Target option. Manual selection of the method for this calculation solves the issue. At least for me. I hope it will be useful for the community.

If this has “fixed” the issue it means Nanite is not working (most common reason is SM6 targets or DX12 aren’t enabled).

When Nanite is working, the fallback mesh is not visible, and changing the fallback triangle percentage will not produce any visual difference because it is only used for things like complex collision.

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Hi Arkiras,

Yes, you are right! Thanks for posting this info. I discovered how Nanite works using UE documentation and understood that my “fix” is not a fix! I was focusing just on the visual look of my tree without understanding the logic of what was going on under the hood. So, my “fix” says instead of properly creating Fallback mesh using the Auto option in the Fallback Target parameter, just use the original Staticmesh tree data for the Fallback mesh. So, yes, visually I received a nice-looking tree because Nanite doesn’t work, but even if Nanite works properly, my tree won’t work efficiently with it because it was calculated/created incorrectly with my “fix”. Thanks, buddy for pointing my attention to it!

Now, I’m going to solve why Nanite isn’t working properly in my scene.

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