Question about Stadium modeling - Esprit Arena

Hey!
I’m modeling the Esprit Arena, located in Düsseldorf, Germany. I’m just doing the inside of the stadium. I’m struggling with the corners and I want to ask how you would model the corners.

As a reference:
http://www.panorama-sammlung.de/images/duessel.jpg

I assume your using an array to model the seat sections?
The corners are just another segment at 45 degrees
they are not rounded (could be wrong), so simply put another segment in, and delete the necessary seats

yes I am using arrays.
Unfortunately it is rounded, see this image:

nobody ever modeled a stadium?