Hi everyone,
This sounds similar to the stuff I've developed for Broadcast installation planning. I construct schematic drawings out of devices (defined as groups of socket symbols and any other graphics needed to make them look nice), and connections (defined as polylines with a connector record containing the start & end socket id's). I can then derive a netlist and calculate cable lengths from a physical layout drawing.
Originally I considered using PIOs but found that I could keep things simpler using symbols and groups, and manage them with simple tools and menu commands. In general, I found that if you store your data as a record in the visual object which represents it everything behaves much nicer. e.g. the connection record is attached to the corresponding polyline so when you delete the polyline the connection disappears. Of course when you move an endpoint... there's always room for improvement.
My Connect Tool uses an event loop to provide a connection path which is orthognally constrained and gives you visual feedback on the path to be drawn. It's possible that a PIO could be made to work more intelligently in this respect but it would be less interactive.
I am now working on the next stage of the project which concerns modelling physical cable paths in buildings and assigning circuits to these. In some ways this might be seen as macro version of PC boards.
It's good to see that others are using VW in this way.
Conrad
