Class EllipseCurve

Creates a 2d curve in the shape of an ellipse

Remarks

Setting the xRadius equal to the yRadius will result in a circle.

Example

const curve = new THREE.EllipseCurve(
  0,  0,  // ax, aY
  10, 10, // xRadius, yRadius
  0,  2 * Math.PI, // aStartAngle, aEndAngle
  false,  // aClockwise
  0       // aRotation
  );
const points = curve.getPoints(50);
const geometry = new THREE.BufferGeometry().setFromPoints(points);
const material = new THREE.LineBasicMaterial({ color: 0xff0000 });
// Create the final object to add to the scene
const ellipse = new THREE.Line(geometry, material);

See

Hierarchy (view full)

Constructors

constructor

Properties

aClockwise aEndAngle aRotation aStartAngle aX aY arcLengthDivisions isEllipseCurve type xRadius yRadius

Methods

clone computeFrenetFrames copy fromJSON getLength getLengths getPoint getPointAt getPoints getSpacedPoints getTangent getTangentAt getUtoTmapping toJSON updateArcLengths

Constructors

constructor

  • new EllipseCurve(aX?, aY?, xRadius?, yRadius?, aStartAngle?, aEndAngle?, aClockwise?, aRotation?): EllipseCurve

  • This constructor creates a new EllipseCurve.

    Parameters

    • Optional aX: number

      The X center of the ellipse. Expects a Float. Default is 0.

    • Optional aY: number

      The Y center of the ellipse. Expects a Float. Default is 0.

    • Optional xRadius: number

      The radius of the ellipse in the x direction. Expects a Float. Default is 1.

    • Optional yRadius: number

      The radius of the ellipse in the y direction. Expects a Float. Default is 1.

    • Optional aStartAngle: number

      The start angle of the curve in radians starting from the positive X axis. Default is 0.

    • Optional aEndAngle: number

      The end angle of the curve in radians starting from the positive X axis. Default is 2 x Math.PI.

    • Optional aClockwise: boolean

      Whether the ellipse is drawn clockwise. Default is false.

    • Optional aRotation: number

      The rotation angle of the ellipse in radians, counterclockwise from the positive X axis. Default is 0.

    Returns EllipseCurve

Properties

aClockwise

aClockwise: boolean

Whether the ellipse is drawn clockwise.

Default Value

`false``

aEndAngle

aEndAngle: number

The end angle of the curve in radians starting from the middle right side.

Remarks

Expects a Float

Default Value

2 * Math.PI

aRotation

aRotation: number

The rotation angle of the ellipse in radians, counterclockwise from the positive X axis (optional).

Remarks

Expects a Float

Default Value

0

aStartAngle

aStartAngle: number

The start angle of the curve in radians starting from the middle right side.

Remarks

Expects a Float

Default Value

0

aX

aX: number

The X center of the ellipse.

Remarks

Expects a Float

Default Value

0

aY

aY: number

The Y center of the ellipse.

Remarks

Expects a Float

Default Value

0

arcLengthDivisions

arcLengthDivisions: number

This value determines the amount of divisions when calculating the cumulative segment lengths of a Curve via .getLengths. To ensure precision when using methods like .getSpacedPoints, it is recommended to increase .arcLengthDivisions if the Curve is very large.

Default Value

200

Remarks

Expects a Integer

Readonly isEllipseCurve

isEllipseCurve: true = true

Read-only flag to check if a given object is of type EllipseCurve.

Remarks

This is a constant value

Default Value

true

Readonly type

type: string

A Read-only string to check if this object type.

Remarks

Sub-classes will update this value.

Default Value

EllipseCurve

xRadius

xRadius: number

The radius of the ellipse in the x direction.

Default Value

1

yRadius

yRadius: number

The radius of the ellipse in the y direction.

Default Value

1

Methods

clone

  • clone(): this

  • Creates a clone of this instance.

    Returns this

computeFrenetFrames

  • computeFrenetFrames(segments, closed?): {
        binormals: Vector3[];
        normals: Vector3[];
        tangents: Vector3[];
    }

  • Generates the Frenet Frames

    Parameters

    • segments: number

      Expects a Integer

    • Optional closed: boolean

    Returns {
        binormals: Vector3[];
        normals: Vector3[];
        tangents: Vector3[];
    }

    Remarks

    Requires a Curve definition in 3D space Used in geometries like TubeGeometry or ExtrudeGeometry.

copy

  • copy(source): this

  • Copies another Curve object to this instance.

    Parameters

    Returns this

fromJSON

  • fromJSON(json): this

  • Copies the data from the given JSON object to this instance.

    Parameters

    • json: {}

      Returns this

    getLength

    • getLength(): number

    • Get total Curve arc length.

      Returns number

    getLengths

    • getLengths(divisions?): number[]

    • Get list of cumulative segment lengths.

      Parameters

      • Optional divisions: number

        Expects a Integer

      Returns number[]

    getPoint

    • getPoint(t, optionalTarget?): Vector2

    • Returns a vector for a given position on the curve.

      Parameters

      • t: number

        A position on the curve. Must be in the range [ 0, 1 ]. Expects a Float

      • Optional optionalTarget: Vector2

        If specified, the result will be copied into this Vector, otherwise a new Vector will be created. Default new T.

      Returns Vector2

    getPointAt

    • getPointAt(u, optionalTarget?): Vector2

    • Returns a vector for a given position on the Curve according to the arc length.

      Parameters

      • u: number

        A position on the Curve according to the arc length. Must be in the range [ 0, 1 ]. Expects a Float

      • Optional optionalTarget: Vector2

        If specified, the result will be copied into this Vector, otherwise a new Vector will be created. Default new T.

      Returns Vector2

    getPoints

    • getPoints(divisions?): Vector2[]

    • Returns a set of divisions +1 points using .getPoint | getPoint(t).

      Parameters

      • Optional divisions: number

        Number of pieces to divide the Curve into. Expects a Integer. Default 5

      Returns Vector2[]

    getSpacedPoints

    • getSpacedPoints(divisions?): Vector2[]

    • Returns a set of divisions +1 equi-spaced points using .getPointAt | getPointAt(u).

      Parameters

      • Optional divisions: number

        Number of pieces to divide the Curve into. Expects a Integer. Default 5

      Returns Vector2[]

    getTangent

    • getTangent(t, optionalTarget?): Vector2

    • Returns a unit vector tangent at t

      Parameters

      • t: number

        A position on the curve. Must be in the range [ 0, 1 ]. Expects a Float

      • Optional optionalTarget: Vector2

        If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

      Returns Vector2

      Remarks

      If the derived Curve does not implement its tangent derivation, two points a small delta apart will be used to find its gradient which seems to give a reasonable approximation.

    getTangentAt

    • getTangentAt(u, optionalTarget?): Vector2

    • Returns tangent at a point which is equidistant to the ends of the Curve from the point given in .getTangent.

      Parameters

      • u: number

        A position on the Curve according to the arc length. Must be in the range [ 0, 1 ]. Expects a Float

      • Optional optionalTarget: Vector2

        If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

      Returns Vector2

    getUtoTmapping

    • getUtoTmapping(u, distance): number

    • Given u in the range [ 0, 1 ],

      Parameters

      • u: number

        Expects a Float

      • distance: number

        Expects a Float

      Returns number

      t also in the range [ 0, 1 ]. Expects a Float.

      Remarks

      u and t can then be used to give you points which are equidistant from the ends of the curve, using .getPoint.

    toJSON

    • toJSON(): {}

    • Returns a JSON object representation of this instance.

      Returns {}

      updateArcLengths

      • updateArcLengths(): void

      • Update the cumulative segment distance cache

        Returns void

        Remarks

        The method must be called every time Curve parameters are changed If an updated Curve is part of a composed Curve like CurvePath, .updateArcLengths() must be called on the composed curve, too.

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