I'm doing a lot of odd-angled routed round pipe, and the odd-angles between the segments are requiring a lot of trig. The trig approximations also mean the segments are disjointed. For smaller systems, that is a cosmetic issue, but later on it gets annoyning from accumulated error. Each segment is separated by an elbow. Gotta not be shy about concocting a forest of reference planes (and also axes of revolution), too. I would rather split the tubing longitudinally (either actually or in effect), like inserting reference planes at 90-deg to, and thru the center of, a pipe-face-end (each end is a circle). I could use that split-plane to get the center of the pipe-end-face. The longitudinal centerline of each pipe segment, as I finish each one, is the objective (for beginning new geo. for each next segment). Q: Can I sketch from circle centers of extrusions (or 360-deg sweeps - yuk) cylinders, at their "free" ends? I just can't get the references that I need for this to be a speedy, segment-by-segment process. (reposting incl. mention that these routings use elbows. Sorry abt the bandwidth. Sysop- del original, please)