How To Set LOD Collision
You can set the Static Mesh to use Complex Collision (per triangle) from any LOD you have imported. This is useful for optimising physics performance, especially if you have lots of Complex Collisions against Static Meshes or Complex Collision Traces.
Import an LOD using the steps from 创建并使用 LOD
In the Static Mesh Settings category of the Details Panel, Set the LOD For Collision to the value of that LOD (0 is the highest resolution mesh, with LODs starting at 1)
As of version 4.12.3, if you enable visualization of collision (either in the Static Mesh Editor, in the Level Editor, or in your game), and are using a lower resolution LOD for collision, you will not see a representation of the collision like you would if a Static Mesh is set to Complex as Simple.