If I have an expression that contains a list of polygons, is there any way I can select every second value from that expression? In the script I am working on I have an expression that contains all the polygons that represent the start and end of a concrete barrier (I am modelling pre-cast concrete barriers with gaps between them). I want to create a BSplineSurface from the polygons using "Ruled" where the even polygons are the "StartCurve" inputs and the odd polygons are the "EndCurve" inputs (so I end up with individual BSplineSurfaces for each barrier with a gap between them). At the moment the only way I can get this to work is by typing the information into the expressions for the StartCurve and EndCurve separately.
As Ed has mentioned that if you are using Update 7 of OpenBuildings Designer then you can try to achieve the same using the Value & Operation node.
Please have a look at the GCT file attached.