Isometric Spool
ISOGEN-style piping isometric from a simple spool description.
Syntax: L dx dy dz = pipe run (mm); F flange|valve|reducer|tee|cap|cross|olet|expansion|elbow|eccentric|reducingtee|coupling|blind|union|filter|sightglass|steamtrap|lateral = fitting at node; # NOTE free text. x=east, y=north, z=up.