CIGAL Reference Manual, Chapter 3 (Functions): perp
usage: vp = perp(v0,v1,v2)
or: vp = perp(v0,vlist)
PERP finds the point closest to vector V0, along the line defined either by the 2 vectors V1 and V2, or by the first two vectors in the list of vectors, VLIST. The result is another vector, VP.
See Also:
LENGTH(3),
LINE(2),
VECTORS(1)