Creating Shadow LODs

Shadow LOD must be exactly named (distance view LOD 10000.0). Containing volume that does not exceed volume of resolution LOD, that mesh is without texture link, closed, triangulated and with sharp edges.

Step by step

1 - Open a 10000 distance view LOD (note it's 10000 not 10.000)

2 - Make the model to use as a shadow inside the 10000 LOD ( for example a weapon should be like 200/300 polys tops, of course the less the better).

PS: Don't forget to delete the textures applied on the Shadows model (if you have any) since it's all black you don't need it mapped.

3 - Inside the Shadow Lod (10000) with the entire model selected go to Structure/Topology/Find non-Closed and check if you have any opened point/faces (they get red if you do and below on your left O2 tells you the amount of them).

4 - If you do have any opened points/faces you must close them, you may try O2 to close them for you, for that go to Structure/Topology/Close, this should close the model for you, however, sometimes you need to do it by hand since this feature inside O2 has some limitations.

PS: Be sure that all points/faces are closed, the best way to know this is by doing the step I wrote you before Structure/Topology/Find non-Closed and see if it gives you 0/0 on the left part below, if you miss this than not only the shadows won't work as most of the times the game will crash while loading the model.

5 - Finally with all points/faces closed, select the entire model and go to Structure/Triangulate (\) and Surfaces/Sharp Edge (U).