function Plane(){
    Shape.call(this);
    this.type = Shape.types.PLANE;

    // World oriented normal
    this.worldNormal = new Vec3();
    this.worldNormalNeedsUpdate = true;

    this.boundingSphereRadius = Number.MAX_VALUE;
}
A plane, facing in the Z direction. The plane has its surface at z=0 and everything below z=0 is assumed to be solid plane. To make the plane face in some other direction than z, you must put it inside a RigidBody and rotate that body. See the demos.
@class Plane
@constructor
@extends Shape
@author schteppe