Forgive my ignorance but I don't know what a "lwpolyline network drawing" is.
And does "I will pass a source point for this network" mean the end point of
are you talking about a point that you have picked thinking it was the end point.
When you say "the direction of polyline should be away from that point" and
"polyline opposite to the flow" are you wanting to see if the pline selected
is the "Starting point" in the pline data and any pline connected to the end
of that has it's "Start Point" equal to the previous pline endpoint.?
Curious why the "Start" & "end" would matter? If your following the vertex points
it just a matter of reversing the list.
And who is this masked man anyway?
Sounds like a question from subbup.