-#create vertex by point projection
-p_on_arc2 = geompy.MakeVertexOnCurveByCoord(Arc, 100, -10, 10)
+# create a vertex by length
+p_on_arc2 = geompy.MakeVertexOnCurveByLength(Arc, 50., False)
+#create a vertex by point projection
+p_on_arc3 = geompy.MakeVertexOnCurveByCoord(Arc, 100, -10, 10)