CurvePrimitive Class

A curve primitive is bounded. A curve primitive maps fractions in 0..1 to points in space. As the fraction proceeds from 0 towards 1, the point moves "forward" along the curve. True distance along the curve is not always strictly proportional to fraction.

  • A LineSegment3d always has proportional fraction and distance.
  • An Arc3d which is true circular has proportional fraction and distance.
  • A LineString3d is not proportional (except for special case of all segments of equal length).
  • A Spiral3d is proportional.
  • A BsplineCurve3d is only proportional for special cases. For fractions outside 0..1, the curve primitive class may either (a) return the near endpoint or (b) evaluate an extended curve.


Extended by


Name Description
constructor(): CurvePrimitive Protected Constructor  
addMappedStrokesToLineString3D(map: StrokeCountMap, linestring: LineString3d): number Evaluate strokes at fractions indicated in a StrokeCountMap.  
announceClipIntervals(_clipper: Clipper, _announce?: AnnounceNumberNumberCurvePrimitive): boolean Find intervals of this curvePrimitive that are interior to a clipper  
appendPlaneIntersectionPoints(plane: PlaneAltitudeEvaluator, result: CurveLocationDetail[]): number Compute intersections of the curve with a plane.  
clone(): CurvePrimitive Abstract Return a deep clone.  
clonePartialCurve(_fractionA: number, _fractionB: number): undefined | CurvePrimitive Return (if possible) a curve primitive which is a portion of this curve.  
cloneTransformed(transform: Transform): undefined | CurvePrimitive Abstract Return a transformed deep clone.  
closestPoint(spacePoint: Point3d, extend: VariantCurveExtendParameter): undefined | CurveLocationDetail Search for a point on the curve that is closest to the spacePoint.  
collectCurvePrimitives(collectorArray?: CurvePrimitive[], smallestPossiblePrimitives: boolean = false, explodeLinestrings: boolean = false): CurvePrimitive[] Return an array containing only the curve primitives.  
collectCurvePrimitivesGo(collectorArray: CurvePrimitive[], _smallestPossiblePrimitives: boolean, _explodeLinestrings: boolean = false): void Return an array containing only the curve primitives.  
computeAndAttachRecursiveStrokeCounts(options?: StrokeOptions, parentMap?: StrokeCountMap): void Attach StrokeCountMap structure to this primitive (and recursively to any children)  
computeStrokeCountForOptions(options?: StrokeOptions): number Abstract Return the stroke count required for given options.  
constructOffsetXY(offsetDistanceOrOptions: number | OffsetOptions): undefined | CurvePrimitive | CurvePrimitive[] Abstract Construct an offset of the instance curve as viewed in the xy-plane (ignoring z).  
curveLength(): number Return the length of the curve.  
curveLengthBetweenFractions(fraction0: number, fraction1: number): number Returns a (high accuracy) length of the curve between fractional positions.  
curveLengthWithFixedIntervalCountQuadrature(fraction0: number, fraction1: number, numInterval: number, numGauss: number = 5): number Run an integration (with a default Gaussian quadrature) with a fixed fractional step  
emitStrokableParts(dest: IStrokeHandler, options?: StrokeOptions): void Abstract Ask the curve to announce points and simple subcurve fragments for stroking.  
emitStrokes(dest: LineString3d, options?: StrokeOptions): void Abstract Add strokes to caller-supplied linestring (function updates dest)  
endPoint(result?: Point3d): Point3d Return the end point of the primitive.  
fractionAndDistanceToPointOnTangent(fraction: number, distance: number): Point3d Construct a point extrapolated along tangent at fraction.  
fractionToCurvature(fraction: number): undefined | number Returns the (absolute) curvature magnitude.  
fractionToFrenetFrame(fraction: number, result?: Transform): undefined | Transform Construct a frenet frame:  
fractionToPoint(fraction: number, result?: Point3d): Point3d Abstract Return the point (x,y,z) on the curve at fractional position.  
fractionToPointAnd2Derivatives(fraction: number, result?: Plane3dByOriginAndVectors): undefined | Plane3dByOriginAndVectors Abstract Return a plane with  
fractionToPointAndDerivative(fraction: number, result?: Ray3d): Ray3d Abstract Return the point (x,y,z) and derivative on the curve at fractional position.  
fractionToPointAndUnitTangent(fraction: number, result?: Ray3d): Ray3d Returns a ray whose origin is the curve point and direction is the unit tangent.  
fractionToSignedXYRadiusOfCurvature(fraction: number): number Construct signed distance from a point on the planar curve to its center of curvature (in xy only).  
getFractionToDistanceScale(): undefined | number If the curve primitive has distance-along-curve strictly proportional to curve fraction, return the scale factor.  
isInPlane(plane: Plane3dByOriginAndUnitNormal): boolean Abstract Ask if the curve is within tolerance of a plane.  
moveSignedDistanceFromFraction(startFraction: number, signedDistance: number, allowExtension: boolean, result?: CurveLocationDetail): CurveLocationDetail (Attempt to) find a position on the curve at a signed distance from start fraction.  
moveSignedDistanceFromFractionGeneric(startFraction: number, signedDistance: number, allowExtension: boolean, result?: CurveLocationDetail): CurveLocationDetail Protected Generic algorithm to search for point at signed distance from a fractional startPoint.  
projectedParameterRange(_ray: Vector3d | Ray3d, _lowHigh?: Range1d): undefined | Range1d Project instance geometry (via dispatch) onto the line of the given ray, and return the extreme fractional  
quickLength(): number Abstract Compute a length for curve which may be a fast approximation to the true length.  
rangeBetweenFractions(fraction0: number, fraction1: number, transform?: Transform): Range3d Returns a (high accuracy) range of the curve between fractional positions  
rangeBetweenFractionsByClone(fraction0: number, fraction1: number, transform?: Transform): Range3d Returns a (high accuracy) range of the curve between fractional positions  
rangeBetweenFractionsByCount(fraction0: number, fraction1: number, count: number, transform?: Transform, extrapolationFactor: number = 0.0): Range3d Returns an approximate range based on a fixed number of evaluations  
reverseInPlace(): void Abstract Reverse the curve's data so that its fractional stroking moves in the opposite direction.  
startPoint(result?: Point3d): Point3d Return the startPoint of the primitive.  
installStrokeCountMap(curve: CurvePrimitive, curveMap: StrokeCountMap, parentMap?: StrokeCountMap): void Static Final install step to save curveMap in curve.  

Inherited methods

Name Inherited from Description
dispatchToGeometryHandler(handler: GeometryHandler): any Abstract GeometryQuery * "double dispatch" call pattern.
extendRange(rangeToExtend: Range3d, transform?: Transform): void Abstract GeometryQuery Extend rangeToExtend by the range of this geometry multiplied by the transform
isAlmostEqual(other: GeometryQuery): boolean GeometryQuery Test for exact structure and nearly identical geometry.
isSameGeometryClass(other: GeometryQuery): boolean Abstract GeometryQuery Test if (other instanceof this.Type).
range(transform?: Transform, result?: Range3d): Range3d GeometryQuery Return the range of the entire (tree) GeometryQuery
tryTransformInPlace(transform: Transform): boolean Abstract GeometryQuery Attempt to transform in place.
tryTranslateInPlace(dx: number, dy: number = 0.0, dz: number = 0.0): boolean GeometryQuery Try to move the geometry by dx,dy,dz
areAlmostEqual(a: undefined | GeometryQuery, b: undefined | GeometryQuery): boolean Static GeometryQuery Apply instance method isAlmostEqual if both are defined.


Name Type Description
curvePrimitiveType AbstractReadonly CurvePrimitiveType String name for schema properties  
geometryCategory Readonly "curvePrimitive" String name for schema properties  
isExtensibleFractionSpace Accessor ReadOnly boolean * Returns true if the curve can be easily extended past its start/end point (i.e., beyond the usual  
parent undefined | any Data attached by various algorithms (e.g.  
strokeData undefined | StrokeCountMap Data attached during stroking for facets.  

Inherited properties

Name Type Inherited from Description
children Accessor ReadOnly undefined | GeometryQuery[] GeometryQuery Return GeometryQuery children for recursive queries.
* leaf classes do not need to implement.

Defined in

Last Updated: 05 June, 2023