Chapter 360: Plane

Core Idea

A two dimensional surface that extends infinitely in 3D space, represented in Hessian normal form by a unit length normal vector and a constant.

Key Concepts

• constant : number: The signed distance from the origin to the plane.
• isPlane : boolean (readonly): This flag can be used for type testing.
• normal : Vector3: A unit length vector defining the normal of the plane.

Reference Tables

Constructor

Signature
new Plane( normal : Vector3, constant : number )

Properties

Property	Description
.constant : number	The signed distance from the origin to the plane.
.isPlane : boolean (readonly)	This flag can be used for type testing.
.normal : Vector3	A unit length vector defining the normal of the plane.

Methods

Method	Description
.applyMatrix4( matrix : Matrix4, optionalNormalMatrix : Matrix4 ) : Plane	Apply a 4x4 matrix to the plane. The matrix must be an affine, homogeneous transform.
.clone() : Plane	Returns a new plane with copied values from this instance.
.coplanarPoint( target : Vector3 ) : Vector3	Returns a coplanar vector to the plane, by calculating the projection of the normal at the origin onto the plane.
.copy( plane : Plane ) : Plane	Copies the values of the given plane to this instance.
.distanceToPoint( point : Vector3 ) : number	Returns the signed distance from the given point to this plane.
.distanceToSphere( sphere : Sphere ) : number	Returns the signed distance from the given sphere to this plane.
.equals( plane : Plane ) : boolean	Returns true if this plane is equal with the given one.
.intersectLine( line : Line3, target : Vector3, clampToLine : boolean ) : Vector3	Returns the intersection point of the passed line and the plane. Returns null if the line does not intersect. Returns the line's starting point if the line is coplanar with the plane.
.intersectsBox( box : Box3 ) : boolean	Returns true if the given bounding box intersects with the plane.
.intersectsLine( line : Line3 ) : boolean	Returns true if the given line segment intersects with (passes through) the plane.
.intersectsSphere( sphere : Sphere ) : boolean	Returns true if the given bounding sphere intersects with the plane.
.negate() : Plane	Negates both the plane normal and the constant.
.normalize() : Plane	Normalizes the plane normal and adjusts the constant accordingly.
.projectPoint( point : Vector3, target : Vector3 ) : Vector3	Projects a the given point onto the plane.
.set( normal : Vector3, constant : number ) : Plane	Sets the plane components by copying the given values.
.setComponents( x : number, y : number, z : number, w : number ) : Plane	Sets the plane components by defining x, y, z as the plane normal and w as the constant.
.setFromCoplanarPoints( a : Vector3, b : Vector3, c : Vector3 ) : Plane	Sets the plane from three coplanar points. The winding order is assumed to be counter-clockwise, and determines the direction of the plane normal.
.setFromNormalAndCoplanarPoint( normal : Vector3, point : Vector3 ) : Plane	Sets the plane from the given normal and coplanar point (that is a point that lies onto the plane).
.translate( offset : Vector3 ) : Plane	Translates the plane by the distance defined by the given offset vector. Note that this only affects the plane constant and will not affect the normal vector.

Key Takeaways

1. Most relevant properties: constant, isPlane, normal.
2. Key methods: applyMatrix4, clone, coplanarPoint, copy.

Connects To

• Source: src/math/Plane.js