Michael,
Can you walk us through the usage scenario?
It would certainly be quite easy to read in a polyline to use as points for pipe. But typically when people ask for this, they also want it to automatically connect to any equipment it is crossing.
We have just found that by the time the mainline is drawn, any initial schematic layout polyline is close, but not always exactly where we end up putting the mainline. But, I'd like to hear your example and how you envision it working.
--J