(Rhino 8)
not sure when, but it s nice to see that the scale commands now accept - at least - 0 as scale factor.
it s still a pity that negative factors (mirroring) are not possible. (gumball does accept negative scales )
the main issue of this topic - a workaround is needed to input 0 als scalefactor for scale1d
scale1d → Base Point → click
Scale Factor or First reference Point → (bug/Papercut)
0 is interpreted as Point 0,0,0
Workaround
…is to use a nested command that produces numeric input: _distance 0 0 (wich is the distance between twice the origin and this is 0)
macro
_scale1d _pause _pause _distance 0 0