Hi, I imported a 3D model from Cinema 4D and I just want to move around with my character. But there’s a certain point in the space that I cant walk through. There’s no object there, It seems like a collition but there’s nothing on sight. What can it be?
I’m a beginner!
Thanks 
Open up the Model in Unreal, at the top is a green button that says Collision, preview the Simple Collision. Your simple collision probably blocks the opening.
If you want to regenerate new collision for your object in Unreal, you can open the Window Convex Decomposition from the windows panel, which has settings for estimating collision.
There is also an option in the model details to tell it to use Complex Collision which will be very expensive if your mesh has lots of triangles, but will use the actual geometry of the mesh to collide against. This is not recommended for a long term solution.
The best solution is to manually author the collision for the asset yourself in your modeling program.
Sometimes when this happens it means that there is something that has collision even though you cant see it.
When you are playing your game turn on collisions to see if you are colliding with something. To do this simply,
Start your game when you are playing, press the `/~ key on your keyboard. This will allow you to enter a command.
You will Enter the Command “Show Collision”
This will show everything you are colliding with!
If you find what you are colliding with, just go to its import settings and make sure you fix its collisions. There are plenty of tutorials online on this. Good luck!