Returns a |
Point representing a unit vector in the direction of the
normal to the plane of the
Path is non-planar.
Point P(1, 1, 1);
Rectangle r(P, 4, 4, 30, 30, 30);
Point N = r.get_normal();
In 3DLDF, plane figures generally have constructors taking a |Point|
argument for the center, a variable number of |real| arguments for the
dimensions, and three |real| arguments for the rotation about the major
axes. The object is first created in the x-z plane, and the
Points are generated to be traversed in the counter-clockwise
direction, when seen from a
Point with a positive y-coordinate.
If no rotation is specified, the normal will point in the direction of
the positive y-axis. If non-zero arguments are used for rotation, the
normal will be rotated accordingly. This direction considered to be
"outside". However, according to Huw
Jones, Computer Graphics Through Key Mathematics, p. 197,
"outside" is considered to be the side of a plane, where the
Points are meant to be traversed in the clockwise direction.
I hope that no problems arise from this discrepancy!