Tube and Pipe constraining

[DRoam]

I'm just getting started using the Tube and Pipe environment for some of my work, and I've got what I'm hoping is a simple question with a simple answer. In the picture attached I've got a 1" pipe dropping down into a 8" pipe which I've disabled because it's a standard part right now and I want to replace it with a tube & pipe run. The thing I seem to have the hardest time doing when routing my pipes is aligning/offsetting my nodes with existing geometry in the assembly. In this case I want the end of the 8" pipe to be 12" offset from the centerline of the 1" pipe, and for the 8" pipe's centerline to be 12" below the bottom of the mezzanine's I-beam (as the standard part it is now). What's the best way to do this in the Tube and Pipe environment?

I tried "Include Geometry" from the "Create" panel but that only lets me create planes, which won't help with offsetting from the 1" centerline. However, SOMETIMES (it's a big sometimes) ALL of the options in the "3D Sketch" tab are available. When that's the case, I can go to the "3D Model" tab and create workpoints, axes, and planes. Sometimes, though, they're not all available, and I'm not able to place anything but planes. Can someone explain why this is and how I can change it so I can always use all the geometry of my assembly?

Also I'd like to know if constraing fittings and point-snapping routes to my assembly geometry in this way is the best way to do Tube and Pipe routes. Will doing this allow my routes to update if the assembly changes? Is it the most reliable/easiest/proper way? Also any good tutorials/articles you know of would be very appreciated. Thanks a lot for any tips.

[blair]

The Tube&Pipe is really designed to look for a starting circular target and a circular ending target. This provides an axis and start/end face. You may be better served to place "fittings" at your start and termination points of your tube run. When you change the location of these fittings, your run should re-adjust.