Buttweld toolbar: Plan 180 LR Return 
Command line: 18LR
Places a 180 degree long radius return in the X-Y plane.
last point
Starts the component at the last point of the previously-created component.
Start
Places the component anywhere in the drawing at any chosen start point.
Corner
Places the component at the corner of two pipes.
otherEnd
Places the start point of the component on the other end.