Using Angles and Setting Up Points

*gp:getPointInput* function, you can
easily establish the primary angle of the path. To draw it, you
need a couple of additional vectors perpendicular to the primary
angle.

*Degrees->Radians* function is
useful. The following code fragment demonstrates how you can set up
your two perpendicular vectors using the PathAngle variable as an argument passed to the
*Degrees->Radians* function:

(setq angp90 (+ PathAngle (Degrees->Radians 90))

angm90 (- PathAngle (Degrees->Radians 90)))

*polar* function:

(setq p1 (polar StartPt angm90 HalfWidth)

p2 (polar p1 PathAngle PathLength)

p3 (polar p2 angp90 Width)

p4 (polar p3 (+ PathAngle (Degrees->Radians 180))

*polar*
function returns a 3D point at a specified angle and distance from
a point. For instance, *polar* locates p2 by projecting p1 a
distance of PathLength along a vector
oriented at an angle of PathAngle,
counter-clockwise from the x-axis.