ARC()                                                                    ARC()

 6 "IRIT Version 8.0"


        CurveType ARC( VectorType StartPos, VectorType Center, VectorType
       EndPos )

       Constructs an arc between the two end points StartPos and EndPos,
       centered at Center. Arc will always be less than 180 degrees, so the
       shortest circular path from StartPos to EndPos is selected. The case
       where StartPos, Center, and EndPos are collinear is illegal, since it
       attempts to define a 180 degrees arc. Arc is constructed as a single
       rational quadratic Bezier curve.


           Arc1 = ARC( vector( 1.0, 0.0, 0.0 ),
                       vector( 1.0, 1.0, 0.0 ),
                       vector( 0.0, 1.0, 0.0 ) );

       constructs a 90 degrees arc, tangent to both the X and Y axes at
       coordinate 1.  See also ARC360