Map check error when using speedtree model with billboards

When I import a speedtree model with the option “both” checked I always get a Map Check error :

[Count] element(s) with zero triangles
in Static Mesh [StaticMesh]

where Count is the number of the trees i have in the scene and Static Mesh is the name of the tree . This error doesn’t occur when using just the 3D LOD’s or just the Billboard one , but when I use both it always happens . I tought it would be fixed by now but I downloaded the latest samples from the speedtree website today and it’s still there . I’m using the free samples on an empty map .
Finally , if there is some other way to use simple billboards for the lowest LOD , I’ll be glad if someone can show it to me . I’ll be populating a very large terrain with alot of trees , so a final billboard LOD is a must .
Thanks !

You will always get that warning if you import both the tree and the billboard, just because that is essentially making two different mesh elements at different LODs. At any one LOD, one of them will not be used and the other will not. We already sort the draw calls in a SpeedTree to put the ones that go away as the tree LODs at the end of the mesh element array to avoid warnings as much as possible, but the addition of the billboard with a different element/material kinda throws a monkey wrench in the works. The warning is harmless, though, as far as I am aware. It’s just warning you of possible performance implications.

Great , so I can just ignore that ?

I have the same problem.

Well, for now you’ll have to, but it shouldn’t cause any problems.

If it really bothers you, you could make an extremely low last geometry LOD, like in the 100 polygon range, and not use the billboard. It may actually end up being lower fill cost than the billboard, but to get a lot on the screen you would probably want to knock the wind effect down to the lowest setting.

i knew this sounded familiar,looked this up last year,came back looking again for a solution. Guess its still a thing??

Currently, yes. It is due to a completely different material coming in with the billboard. But as I mentioned above, you can ignore it.