Arc
The arc entity is defined by a plane in which the arc lies. The arc is centered at the origin, and is parameterized by the angle of rotation from the first plane unit vector in the direction of the second plane vector. The start and end angle parameters of the arc and the radius are also given. The direction of the arc is counterclockwise if the start angle is less than the end angle, otherwise it is clockwise.
Data Format:
vector1[3] First vector that defines the
plane of the arc
vector2[3] Second vector that defines the
plane of the arc
origin[3] Origin that defines the plane
of the arc
start_angle Angular parameter of the starting
point
end_angle Angular parameter of the ending
point
radius Radius of the arc.
Parameterization:
t' (the unnormalized parameter) is
(1 - t) * start_angle + t * end_angle
(x, y, z) = radius * [cos(t') * vector1 +
sin(t') * vector2] + origin