Chapter 365: Sphere

Core Idea

An analytical 3D sphere defined by a center and radius. This class is mainly used as a Bounding Sphere for 3D objects.

Key Concepts

center : Vector3: The center of the sphere
isSphere : boolean (readonly): This flag can be used for type testing.
radius : number: The radius of the sphere.

Reference Tables

Constructor

Signature
`new Sphere( center : Vector3, radius : number )`

Properties

Property	Description
`.center : Vector3`	The center of the sphere
`.isSphere : boolean (readonly)`	This flag can be used for type testing.
`.radius : number`	The radius of the sphere.

Methods

Method	Description
`.applyMatrix4( matrix : Matrix4 ) : Sphere`	Transforms this sphere with the given 4x4 transformation matrix.
`.clampPoint( point : Vector3, target : Vector3 ) : Vector3`	Clamps a point within the sphere. If the point is outside the sphere, it will clamp it to the closest point on the edge of the sphere. Points already inside the sphere will not be affected.
`.clone() : Sphere`	Returns a new sphere with copied values from this instance.
`.containsPoint( point : Vector3 ) : boolean`	Returns `true` if this sphere contains the given point inclusive of the surface of the sphere.
`.copy( sphere : Sphere ) : Sphere`	Copies the values of the given sphere to this instance.
`.distanceToPoint( point : Vector3 ) : number`	Returns the closest distance from the boundary of the sphere to the given point. If the sphere contains the point, the distance will be negative.
`.equals( sphere : Sphere ) : boolean`	Returns `true` if this sphere is equal with the given one.
`.expandByPoint( point : Vector3 ) : Sphere`	Expands the boundaries of this sphere to include the given point.
`.fromJSON( json : Object ) : Sphere`	Returns a serialized structure of the bounding sphere.
`.getBoundingBox( target : Box3 ) : Box3`	Returns a bounding box that encloses this sphere.
`.intersectsBox( box : Box3 ) : boolean`	Returns `true` if this sphere intersects with the given box.
`.intersectsPlane( plane : Plane ) : boolean`	Returns `true` if this sphere intersects with the given plane.
`.intersectsSphere( sphere : Sphere ) : boolean`	Returns `true` if this sphere intersects with the given one.
`.isEmpty() : boolean`	Returns `true` if the sphere is empty (the radius set to a negative number).
`.makeEmpty() : Sphere`	Makes this sphere empty which means in encloses a zero space in 3D.
`.set( center : Vector3, radius : number ) : Sphere`	Sets the sphere's components by copying the given values.
`.setFromPoints( points : Array.<Vector3>, optionalCenter : Vector3 ) : Sphere`	Computes the minimum bounding sphere for list of points. If the optional center point is given, it is used as the sphere's center. Otherwise, the center of the axis-aligned bounding box encompassing …
`.toJSON() : Object`	Returns a serialized structure of the bounding sphere.
`.translate( offset : Vector3 ) : Sphere`	Translates the sphere's center by the given offset.
`.union( sphere : Sphere ) : Sphere`	Expands this sphere to enclose both the original sphere and the given sphere.

Key Takeaways

Most relevant properties: center, isSphere, radius.
Key methods: applyMatrix4, clampPoint, clone, containsPoint.

Connects To

Source: src/math/Sphere.js