Strange LOD import issue

Hi all,

I purchased Nature Package from UE Marketplace which contains a nice set of trees. I wanted to put a lot of them to my landscape and I realized that the trees in the package have too many triangles and vertices to maintain good FPS.

For example, the pine01 has 9340 triangles and 10647 vertices on LOD0 and 5041 triangles and 7739 vertices on LOD1. So, to have more LOD levels and simpler trees, I wanted to test Simplygon (https://www.simplygon.com/).

This is where I started from…

Image link: http://i.imgur.com/WsmlL4a.png

…and this is what I did:

  1. Exported PineTree01 static mesh from UE4 to FBX file.

  2. Created multiple LODs using Simplygon application from the previosly mentioned FBX.

Image link: http://i.imgur.com/sAKKocE.png

  1. Imported the FBX created by Simplygon as static mesh to UE4. I used these settings create a separate static mesh for each LOD.

Image link: http://i.imgur.com/W5Sdyux.png

This is how LOD1 static mesh looks after adding materials. I know, the trunk doesn’t look very good (that isn’t my main concern at this point :slight_smile: but leaves are okayish, I think.

Image link: http://i.imgur.com/eErCXox.png

At this point I had separate static mesh for each LOD in UE4 and I realized that I cannot combine them to one mesh without saving them as separate FBX files because UE4’s import new LOD feature seems to work only with FBX files. Well, I decided to export each LOD static mesh to FBX files then (PineTree01_LOD1.fbx, PineTree01_LOD2.fbx, etc.)

  1. Imported LOD1 to the main static mesh from PineTree01_LOD1.fbx. This is how it looks:

Image link: http://i.imgur.com/0WLfmfF.png

  1. Added materials. The tree looks a little weird, doesn’t it?

Image link: http://i.imgur.com/c6moDyw.png

Does anyone know if I am doing something wrong or might this be a bug in export FBX and/or import LOD feature in UE4? I’m using UE 4.7 preview 7. Many thanks in advance for any help!

Best regards,
Tomi

Hi Tkorkalainen,

Can you post a screenshot of your UV channels 0, 1, and 2.

Also, can you apply this checker pattern in the material slot?

I used this when troubleshooting a lot of UV issues because you can see where the stretching and scaling issues are happening.

It may be that when you exported the FBX it wiped or decimated the UVs beyond usable, which may mean you will need to manually set these up again via a modeling program.