New artist, working with collision on complex geometry.

I am new to working in Unreal and I am trying to get complex meshes for map architecture to have collision that can be traversed by the player.
Here are some images of the model I am working with.


Obviously the player is supposed to be able to go on the walkway and up the stairs smoothly.
This is all one mesh/asset so I cannot use Auto Convex Collision and still have the interior accessible to the player.
I have tried using UCX geometry in 3ds Max but had issues with some of the collision not matching the geometry when exported and opened in Unreal 4.13.0.
Here is an example of my geometry:


And here is what Unreal was converting/reading it as:


I have started to just add in basic collision geometry and editing it to match the areas I would need it, but however this is a very slow and unorthodox method I am sure.


A collision mesh cannot be concave, a V shape would be treated as a triangle. You will have to use multiple collision meshes for that spiral staircase.

I realized that last night after posting, thank you very much!