Add an example with a polyline from a numpy array

CadQuery/Examples/Ex028_Numpy.py

@@ -0,0 +1,26 @@
+# This example is meant to be used from within the CadQuery module of FreeCAD.
+import numpy as np
+import cadquery
+from Helpers import show
+
+# Square side and offset in x and y.
+side = 10
+offset = 5
+
+# Define the locations that the polyline will be drawn to/thru.
+# The polyline is defined as numpy.array so that operations like translation
+# of all points are simplified.
+pts = np.array([
+    (0, 0),
+    (side, 0),
+    (side, side),
+    (0, side),
+    (0, 0),
+]) + [offset, offset]
+
+result = cadquery.Workplane('XY') \
+    .polyline(pts).extrude(2) \
+    .faces('+Z').workplane().circle(side / 2).extrude(1)
+
+# Render the solid
+show(result)