In 7 SR9, but not in 6 SR35,
When Perpendicular to edge is disabled in the Match Curve window or when PerpendicularToEdge is set to No via -Match, PerpendicularToEdge is missing from future executions of -Match, replaced with the Join and AverageCurves options. A way to get it back in the same Rhino session is to reenable Perpendicular to edge in the Match Curve window.
Model for testing: Test_-Match.3dm (138.9 KB)
For example, running this macro twice:
_-Match
_Pause
_SurfaceEdge
_Pause
_Pause
_Mode=Tangency
_PreserveOtherEnd=Tangency
_PerpendicularToEdge=No
_Enter
produces
Command: _-Match
Select open curve to change - pick near end to change: _Pause
Select open curve to change - pick near end to change
Select open curve to match - pick near end to match ( SurfaceEdge MatchTo=CurveEnd ): _SurfaceEdge
Select surface edge to match: _Pause
Select surface edge to match
Point on surface edge: _Pause
Point on surface edge
Press Enter to match ( Mode=Tangency PreserveOtherEnd=Tangency PerpendicularToEdge=Yes ): _Mode=Tangency
Press Enter to match ( Mode=Tangency PreserveOtherEnd=Tangency PerpendicularToEdge=Yes ): _PreserveOtherEnd=Tangency
Press Enter to match ( Mode=Tangency PreserveOtherEnd=Tangency PerpendicularToEdge=Yes ): _PerpendicularToEdge=No
Press Enter to match ( Mode=Tangency PreserveOtherEnd=Tangency PerpendicularToEdge=No ): _Enter
Press Enter to match ( Mode=Tangency PreserveOtherEnd=Tangency PerpendicularToEdge=No )
Command: _-Match
Select open curve to change - pick near end to change: _Pause
Select open curve to change - pick near end to change
Select open curve to match - pick near end to match ( SurfaceEdge MatchTo=CurveEnd ): _SurfaceEdge
Select surface edge to match: _Pause
Select surface edge to match
Point on surface edge: _Pause
Point on surface edge
Press Enter to match ( Mode=Tangency Join=None PreserveOtherEnd=Tangency AverageCurves=No ): _Mode=Tangency
Press Enter to match ( Mode=Tangency Join=None PreserveOtherEnd=Tangency AverageCurves=No ): _PreserveOtherEnd=Tangency
Press Enter to match ( Mode=Tangency Join=None PreserveOtherEnd=Tangency AverageCurves=No ): _PerpendicularToEdge=No
Unknown command: _PerpendicularToEdge=No
Press Enter to match ( Mode=Tangency Join=None PreserveOtherEnd=Tangency AverageCurves=No ): _Enter
Press Enter to match ( Mode=Tangency Join=None PreserveOtherEnd=Tangency AverageCurves=No )