Hi Simon,
Extrusion and Revolution are working from python as well as in the old geo-files.
There was one change: point indices are now 0-based.
The spline.AddPoint(x,y) returns the index of the new point. You can use that to be independent of Netgen-enumeration convention (see modified example)
There was another small but essential typo in the script (used extr instead of ext).
Best,
Joachim