API Reference › core-geometry› Bspline › BSpline1dNd

BSpline1dNd Class

Knots and poles for a B-spline function mapping R to R^n.

  • The "pole" (aka control point) of this class is a block of poleLength numbers.
  • Derived classes (not this class) assign meaning such as x,y,z,w.
  • For instance, an instance of this class with poleLength===3 does not know if its poles are x,y,z or weighted 2D x,y,w.

Methods

Name Description
constructor(numPoles: number, poleLength: number, order: number, knots: KnotVector): BSpline1dNd Protected Initialize arrays for given spline dimensions.  
addKnot(knot: number, totalMultiplicity: number): boolean Insert the knot and resulting pole into the instance, optionally multiple times.  
evaluateBasisFunctionsInSpan(spanIndex: number, spanFraction: number, f: Float64Array, df?: Float64Array, ddf?: Float64Array): boolean Evaluate the order basis functions (and optionally one or two derivatives) at a given fractional position within  
evaluateBuffersAtKnot(u: number, numDerivative: number = 0): void Evaluate the B-spline function and optional derivatives at the given parameter in knot space.  
evaluateBuffersInSpan(spanIndex: number, spanFraction: number): void * Evaluate the basis functions at spanIndex and fraction.  
evaluateBuffersInSpan1(spanIndex: number, spanFraction: number): void * Evaluate the basis functions and one derivative at spanIndex and fraction.  
getPoint3dPole(i: number, result?: Point3d): undefined | Point3d Copy 3 values of pole i into a point.  
reverseInPlace(): void Reverse the instance poles and knots in place.  
spanFractionToKnot(spanIndex: number, spanFraction: number): number Map a span index and span fraction to knot value.  
sumPoleBuffer1ForSpan(spanIndex: number): void Compute the linear combination of the given span's poles and the weights in basisBuffer1, and store this  
sumPoleBuffer2ForSpan(spanIndex: number): void Compute the linear combination of the given span's poles and the weights in basisBuffer2, and store this  
sumPoleBufferForSpan(spanIndex: number): void Compute the linear combination of the given span's poles and the weights in basisBuffer, and store this point  
testClosablePolygon(mode?: BSplineWrapMode): boolean Test if the leading and trailing poles are replicated in the manner of a "closed" B-spline function with wraparound  
testCloseablePolygon(mode?: BSplineWrapMode): boolean Test if the leading and trailing polygon coordinates are replicated in the manner of a "closed" bspline polygon Deprecated  
create(numPoles: number, poleLength: number, order: number, knots: KnotVector): BSpline1dNd Static Create a BSpline1dNd.  

Properties

Name Type Description
basisBuffer Float64Array Values of the order relevant B-spline basis functions at a parameter.  
basisBuffer1 Float64Array Derivatives of the order relevant B-spline basis functions at a parameter.  
basisBuffer2 Float64Array Second derivatives of the order relevant B-spline basis functions at a parameter.  
degree Accessor ReadOnly number (property accessor) Return the degree of the polynomials.  
knots KnotVector Knots of the bspline.  
numPoles Accessor ReadOnly number (property accessor) Return the number of poles.  
numSpan Accessor ReadOnly number (property accessor) Return the number of bezier spans (including null spans at multiple knots).  
order Accessor ReadOnly number (property accessor) Return the order (one more than degree) of the polynomials.  
packedData Float64Array Poles packed in blocks of poleLength doubles.  
poleBuffer Float64Array Temporary to hold a single point.  
poleBuffer1 Float64Array Temporary to hold a single derivative vector.  
poleBuffer2 Float64Array Temporary to hold a single second derivative vector.  
poleLength number The number of numeric values per pole.  

Defined in

Last Updated: 29 October, 2025