Generates a keypoint at a specified location on an existing line.
Number of the line. If negative, the direction of line (as
RATIO) is reversed. If
P, graphical picking is enabled and all remaining command fields are ignored
(valid only in the GUI).
Ratio of line length to locate keypoint. Must be between 0.0 and 1.0. Defaults to 0.5 (divide the line in half).
Number to be assigned to keypoint generated at division location (defaults to lowest available keypoint number [NUMSTR]).