API Reference › core-geometry› Curve › CurveChainWithDistanceIndex

CurveChainWithDistanceIndex Class

CurveChainWithDistanceIndex is a CurvePrimitive whose fractional parameterization is proportional to true distance along a path.

  • For example if the total length of the chain is L, then the distance along the chain from parameters t0 to t1 is easily computed as L*(t1-t0).
  • In this way the CurveChainWithDistanceIndex provides a global arc length parameterization for a CurveChain.
  • A CurveChainWithDistanceIndex can be created from any CurveChain, but a Path is stored internally.
  • Adding a CurveChainWithDistanceIndex to a CurveChain does not preserve the distance index; instead the internal path children are added directly to the CurveChain.

Extends

Methods

Name Description
chainDistanceToChainFraction(distance: number): number Convert distance along the chain to fraction along the chain.  
chainDistanceToFragment(distance: number, allowExtrapolation: boolean = false): undefined | PathFragment Return the PathFragment object at the given distance along the chain.  
chainDistanceToFragmentIndex(distance: number, allowExtrapolation: boolean = false): undefined | number Protected Return the index of the PathFragment at the given distance along the chain.  
clone(options?: StrokeOptions): CurveChainWithDistanceIndex Return a deep clone with its own distance index.  
clonePartialCurve(fractionA: number | CurveLocationDetail, fractionB: number | CurveLocationDetail, options?: StrokeOptions): undefined | CurveChainWithDistanceIndex Return a portion of this curve with its own distance index.  
cloneTransformed(transform: Transform, options?: StrokeOptions): undefined | CurveChainWithDistanceIndex Create a clone, transformed and with its own distance index.  
closestPoint(spacePoint: Point3d, extend: VariantCurveExtendParameter, result?: CurveLocationDetail): undefined | CurveLocationDetail Search for the curve point that is closest to the spacePoint.  
collectCurvePrimitivesGo(collectorArray: CurvePrimitive[], smallestPossiblePrimitives: boolean = false, explodeLineStrings: boolean = false): void Return an array containing only the curve primitives.  
computeAndAttachRecursiveStrokeCounts(options?: StrokeOptions, parentStrokeMap?: StrokeCountMap): void Construct StrokeCountMap for each child, accumulating data to stroke count map for this primitive.  
computeChainDetail(childDetail: CurveLocationDetail, result?: CurveLocationDetail): undefined | CurveLocationDetail Compute the global chain detail corresponding to a local child detail.  
computeStrokeCountForOptions(options?: StrokeOptions): number Return the stroke count required for given options.  
constructOffsetXY(offsetDistanceOrOptions: number | OffsetOptions): undefined | CurvePrimitive | CurvePrimitive[] Construct an offset of each child as viewed in the xy-plane (ignoring z).  
curveAndChildFractionToFragment(curve: CurvePrimitive, fraction: number): undefined | PathFragment Return the PathFragment object containing the point at the given fraction of the given child curve.  
curveLength(): number Returns the total length of this curve.  
curveLengthBetweenFractions(fraction0: number, fraction1: number): number Return a (high accuracy and positive) length of the curve between fractional positions  
dispatchToGeometryHandler(handler: GeometryHandler): any Second step of double dispatch: call this._path.dispatchToGeometryHandler (handler)  
emitStrokableParts(dest: IStrokeHandler, options?: StrokeOptions): void Ask the curve to announce points and simple subcurve fragments for stroking.  
emitStrokes(dest: LineString3d, options?: StrokeOptions): void Add strokes to caller-supplied linestring  
endPoint(result?: Point3d): Point3d Return the end point of of this curve.  
extendRange(rangeToExtend: Range3d, transform?: Transform): void Extend rangeToExtend as needed to include these curves (optionally transformed)  
fractionToPoint(fraction: number, result?: Point3d): Point3d Return the point (x,y,z) on the curve at fractional position along the chain.  
fractionToPointAnd2Derivatives(fraction: number, result?: Plane3dByOriginAndVectors): undefined | Plane3dByOriginAndVectors Return a plane with  
fractionToPointAndDerivative(fraction: number, result?: Ray3d): Ray3d Return the point (x,y,z) and derivative on the curve at fractional position.  
fractionToPointAndUnitTangent(fraction: number, result?: Ray3d): Ray3d Return the point (x,y,z) and normalized derivative on the curve at fractional position.  
isAlmostEqual(other: GeometryQuery): boolean Test for equality conditions.  
isInPlane(plane: Plane3dByOriginAndUnitNormal): boolean Ask if the curve is within tolerance of a plane.  
isSameGeometryClass(other: GeometryQuery): boolean Test if other is a CurveChainWithDistanceIndex  
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.  
projectedParameterRange(ray: Vector3d | Ray3d, lowHigh?: Range1d): undefined | Range1d Project instance geometry (via dispatch) onto the given ray, and return the extreme fractional parameters of  
quickLength(): number Returns the total length of the path.  
reverseInPlace(): void Reverse the curve's data so that its fractional stroking moves in the opposite direction.  
startPoint(result?: Point3d): Point3d Return the start point of this curve.  
tryTransformInPlace(transform: Transform): boolean Attempt to transform in place.  
createCapture(path: CurveChain, options?: StrokeOptions): CurveChainWithDistanceIndex Static Capture (not clone) a path into a new CurveChainWithDistanceIndex.  
getClosestPointTestCounts(clear: boolean = true): { numAssigned: number, numCalls: number, numCandidate: number, numTested: number } Static Return an object summarizing closest point test counts.  

Inherited methods

Name Inherited from Description
addMappedStrokesToLineString3D(map: StrokeCountMap, linestring: LineString3d): number Inherited CurvePrimitive Evaluate strokes at fractions indicated in a StrokeCountMap.
allTangents(spacePoint: Point3d, options?: TangentOptions): undefined | CurveLocationDetail[] Inherited CurvePrimitive Return all points P on the curve such that the line containing spacePoint and P is tangent to the curve in
announceClipIntervals(_clipper: Clipper, _announce?: AnnounceNumberNumberCurvePrimitive): boolean Inherited CurvePrimitive Find intervals of this curvePrimitive that are interior to a clipper
appendPlaneIntersectionPoints(plane: PlaneAltitudeEvaluator, result: CurveLocationDetail[]): number Inherited CurvePrimitive Compute intersections of the curve with a plane.
closestTangent(spacePoint: Point3d, options?: TangentOptions): undefined | CurveLocationDetail Inherited CurvePrimitive Return the point P on the curve such that the line containing spacePoint and P is tangent to the curve in
collectCurvePrimitives(collectorArray?: CurvePrimitive[], smallestPossiblePrimitives: boolean = false, explodeLinestrings: boolean = false): CurvePrimitive[] Inherited CurvePrimitive Return an array containing only the curve primitives.
curveLengthWithFixedIntervalCountQuadrature(fraction0: number, fraction1: number, numInterval: number, numGauss: number = 5): number Inherited CurvePrimitive Run an integration (with a default Gaussian quadrature) with a fixed fractional step
emitTangents(spacePoint: Point3d, announceTangent: (tangent: CurveLocationDetail) => any, options?: TangentOptions): void Inherited CurvePrimitive Announce all points P on the curve such that the line containing spacePoint and P is tangent to the curve in
fractionAndDistanceToPointOnTangent(fraction: number, distance: number): Point3d Inherited CurvePrimitive Construct a point extrapolated along tangent at fraction.
fractionToCurvature(fraction: number): undefined | number Inherited CurvePrimitive Returns the (absolute) curvature magnitude.
fractionToFrenetFrame(fraction: number, result?: Transform): undefined | Transform Inherited CurvePrimitive Construct a frenet frame:
fractionToSignedXYRadiusOfCurvature(fraction: number): number Inherited CurvePrimitive Construct signed distance from a point on the planar curve to its center of curvature (in xy only).
getFractionToDistanceScale(): undefined | number Inherited CurvePrimitive If the curve primitive has distance-along-curve strictly proportional to curve fraction, return the scale factor.
isPhysicallyClosedCurve(tolerance: number = Geometry.smallMetricDistance, xyOnly: boolean = false): boolean Inherited CurvePrimitive Whether the start and end points are defined and within tolerance.
moveSignedDistanceFromFractionGeneric(startFraction: number, signedDistance: number, allowExtension: boolean, result?: CurveLocationDetail): CurveLocationDetail Protected Inherited CurvePrimitive Generic algorithm to search for point at signed distance from a fractional startPoint.
range(transform?: Transform, result?: Range3d): Range3d Inherited CurvePrimitive Return the range of the entire GeometryQuery tree.
rangeBetweenFractions(fraction0: number, fraction1: number, transform?: Transform): Range3d Inherited CurvePrimitive Returns the range of the curve between fractional positions.
rangeBetweenFractionsByClone(fraction0: number, fraction1: number, transform?: Transform): Range3d Inherited CurvePrimitive Returns a high accuracy range of the curve between fractional positions using clonePartialCurve.
rangeBetweenFractionsByCount(fraction0: number, fraction1: number, count: number, transform?: Transform, extrapolationFactor: number = 0.0): Range3d Inherited CurvePrimitive Returns an approximate range based on a fixed number of evaluations.
tryTranslateInPlace(dx: number, dy: number = 0.0, dz: number = 0.0): boolean Inherited CurvePrimitive Try to move the geometry by dx,dy,dz.
areAlmostEqual(a: GeometryQuery, b: GeometryQuery): boolean Static Inherited CurvePrimitive Apply instance method isAlmostEqual if both are defined.
installStrokeCountMap(curve: CurvePrimitive, curveMap: StrokeCountMap, parentMap?: StrokeCountMap): void Static Inherited CurvePrimitive Final install step to save curveMap in curve.

Properties

Name Type Description
curvePrimitiveType Readonly "curveChainWithDistanceIndex" String name for schema properties  
fragments Accessor ReadOnly PathFragment[] Reference to the fragments array.  
path Accessor ReadOnly Path Reference to the contained path.  

Inherited properties

Name Type Inherited from Description
children Accessor Inherited ReadOnly undefined | GeometryQuery[] CurvePrimitive Return GeometryQuery children for recursive queries.
* leaf classes do not need to implement.
geometryCategory Readonly Inherited "curvePrimitive" CurvePrimitive String name for schema properties
isExtensibleFractionSpace Accessor Inherited ReadOnly boolean CurvePrimitive * Returns true if the curve can be easily extended past its start/end point (i.e., beyond the usual
fraction space [0,1]). Otherwise, returns false.
* Base class default implementation returns false.
* These classes (and perhaps others in the future) will return true:
* LineSegment3d
* LineString3d
* Arc3d
parent Inherited any | undefined CurvePrimitive Data attached by various algorithms (e.g.
strokeData Inherited StrokeCountMap | undefined CurvePrimitive Data attached during stroking for facets.

Defined in

Last Updated: 24 October, 2025