I've been contemplating this problem too. The best I've been able to do is create a 2d/3d symbol for the boom itself, with the 2d boom at an angle and the 3d boom straight up. Lights are inserted along the line of the 2d boom, get the Z-axis set by hand, are moved to the pipe origin to draw the beam, and then moved back, one by one. To do a 3d rendering, I drag the units on top of one another in 2d, then view in other views. It's awkward, but you get a hangable 2d plot.