Hi Marco, well there are 2 different ways PlanarSrf can be used. If you have curves selected it will build just a planar surface through those curves, if you only want the surface itself you would probably want to use it this way. The other way it can be used is if you select an entire joined surface object with holes in it - when you run it this way it will build the planar surfaces through naked edges that form closed planar loops and also join them with the main object. When run this second way the output object is not going to be just the planar surface, it's the whole entire joined object.

So if you want only the planar surfaces it would probably be good to give PlanarSrf curves for its input objects and then you should be able to do the .update() .getCreatedObjects() .commit() sequence.

- Michael