Built-in Mathematica Symbol

BSplineCurve

BSplineCurve[{pt₁, pt₂, ...}]
is a graphics primitive which represents a non-uniform rational B-spline curve with control points pt_i.

BSplineCurve can be used in both Graphics and Graphics3D (two- and three-dimensional graphics).

The positions of control points can be specified either in ordinary coordinates as {x, y} or {x, y, z}, or in scaled coordinates as Scaled[{x, y}] or Scaled[{x, y, z}].

SplineDegree	Automatic	degree of polynomial basis
SplineKnots	Automatic	knot sequence for spline
SplineWeights	Automatic	control point weights
SplineClosed	False	whether to make the spline closed

The option setting SplineDegree->d specifies that the underlying polynomial basis should have maximal degree d.

By default, knots are chosen uniformly in parameter space, with additional knots added so that the curve starts at the first control point and ends at the last one.

With an explicit setting for SplineKnots, the degree of the polynomial basis is determined from the number of knots specified and the number of control points.

With the default setting SplineWeights->Automatic, all control points are chosen to have equal weights, corresponding to a polynomial B-spline curve.

Curve thickness can be specified using Thickness or AbsoluteThickness, as well as Thick and Thin.

Curve dashing can be specified using Dashing or AbsoluteDashing, as well as Dashed, Dotted, etc.

Curve shading or coloring can be specified using CMYKColor, GrayLevel, Hue, Opacity or RGBColor.

Individual coordinates and lists of coordinates in BSplineCurve can be Dynamic objects.

A B-spline curve and its control points in 2D:

A B-spline curve and its control points in 3D: