Okay so I have been messing around with this for a while, I have this old church model and i’m trying to get a complex collision bound on it. I am no good with blender and new to 3ds (mainly a C4D user). The model was made with 3ds so I figured I would use that to make the collision bounds, I copied all the parts of the church then pasted them and renamed the pasted version to UCX_(name) but UE4 does not pick it up? I could be doing something super wrong here but I have no idea, any help would be awesome. Note: I do need to be able to walk in to the church and up the stairs, thats the issue im having.
Then you have no luck, with UCX_copy, if it should be walkable.
I use Blender, can give no tips for 3dsmax *.fbx export.
Start with a floor and a stairway, to understand the concept of blocking out collisions with primitives.
Google much stuff ^^
Take a look at this tutorial: 
Sometimes it works when you just copy and paste everything, but it’s not recommended, because some “collision artifacts” could appear. So it’s better when you just use simple shapes for your collision.
After you have created your collision boxes, you will have to import it. In the import window make sure to disable “one convex hull per…” and "auto generate collision