I put together a basic example showing how to use the external geometry library inside of Python. A screenshot and the dynamo patch is attached. It uses some points to construct a curve, then it extrudes the curve. Here's the Python script:
# Default imports
path = r'C:AutodeskDynamoCore'
exec_path = r'C:AutodeskDynamoCoredll'
from Autodesk.LibG import *
#The input to this node will be stored in the IN variable.
dataEnteringNode = IN
p1 = Point.by_coordinates(0, 0, 0);
p2 = Point.by_coordinates(10, 5, 0);
p3 = Point.by_coordinates(20, 10, 0);
p4 = Point.by_coordinates(30, -15, 0);
# We have to construct a new PointList object, due to the Python -> C++ link
# the points are put into a python array, and used to construct a PointList
# All types have a “List” type, eg CurveList, SolidList, GeometryList etc etc
list= PointList([p1, p2, p3, p4]);
dir = Vector.by_coordinates(0, 0, 1);
curve = BSplineCurve.by_points(list);
surf = curve.extrude(dir, 30);
#Assign your output to the OUT variable
OUT = surf
The rudimentary documentation for this library is here: http://designscript.org/libg/classds_1_1Geometry.html Unfortunately it’s for the C++ library, so it’s mainly useful for getting method names. Ignore the ‘*’s and ‘&’s
Hope this is enough to get you started. Let me know if you have any more specific questions.