@Anonymous wrote:
... a command when using PLINE that creates a new baseline. To allow new angles to be set as though the last line was zero degree baseline.
.....
Since you ask this in the specific context of using PLINE, I'm wondering whether you really mean is that you want new angles for each segment to be set as though the most recent line segment in the Polyline you're drawing was at 0 degrees as a reference angle. If that's what you're looking for, it will not be possible with UCS, which can't be used transparently [i.e. requires closing the Polyline command].
I do have a routine that continues a Polyline. It asks you to pick something, which can be a Polyline or just a Line or Arc, and it continues with a Polyline command from the end nearest where you pick. It knows which direction that's headed in case you want an arc segment continuing tangent from there. When you're done, it joins what you did to the selected object, and if you pick Close, includes that object rather than closing back to the point where you started your continuation. I can imagine it might be possible to construct a routine that would incorporate that kind of functionality, one segment at a time, and if the latest segment was a line, change the UCS in between. Does that sound like it would do what you want?
Kent Cooper, AIA