Create net surface! Mastercam x4

[juanmauricio]

I have a problem to create net surface, when I select the model with window option and set the "Sketch approximate start point", mastercam show me an error: "All along curves must be open or closed", and when I select almost all the model whit window option, mastercam create the surface. What is the correct method to create a net surface? Please I need help!!!

[Superman]

DO NOT use the window method ( windowing has no sense of chains, each entity is a separate "chain" )

Selection is down by picking (L-click) on the required chain/s in an order sequence