Using Dynamo, you can automate stadium seating and save a whole lot of time. All you need to do – is select an edge of the slab that will host your seats, and execute the Dynamo graph. The following process is automatic: the graph places seats at the edge of the curved slab, preserving the desired spacing between seats and setting orientation.
All the necessary nodes to get each seat rotation (e.g. “Element.GetRotation”) could be found @ Zhukoven.com package).