The problem with all of these methods is I don't find them to be very straightforward. The other day I saw a question posted on the forums about how to create a helix and it got me thinking again if there was a better way to do this. (Dynamo was the obvious choice, but we'll come back to that).
So I asked myself, is there any other tool or object in Revit that creates a spiral or helix form? That's when spiral stairs popped into my head! So I opened up Revit and started to play, and this is what I came up with.
Dynamo is also another way you could go about creating a helix & spiral forms in Revit. HyunnWoo Kim posted again in 2015 and created a great video demonstrating the method.