When Reimporting a mesh the collision that is created using the methods in the Static Mesh Editor will be wiped if there was not previously setup UCX custom collision.
1. Open UE4
2. Import a static mesh
3. Import Options: Disable Generate Collision
4. Open the Static Mesh Editor
5. Add Box Collision
7. Reimport the asset and collision will be gone.
*If in 4.8 or MAIN do not leave the Static Mesh Editor window open. This will crash, reported in [Link Removed]*
Results: Any collision setup here is wiped on reimport
Expected: Collision will not be wiped on reimport
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-16999 in the post.