Of curves and polylines

Of course, it is necessary to convert all lines to polylines and layers to prevent excessive hair-pulling and cursing. Problem is, splines, arcs and ellipses don't convert to polylines easily. It took hours of trawling through tutorials online and lots of trial and error to get it right. Splines can be turned into polylines by using the FLATTEN command, but ellipses are something else: http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=2881972&linkID=9240817

In the end, I tried extruding a single cycloidal vault and test rendered it. This is the result:

Not bad at all, if I do say so myself.