Struct NurbsCurve 

pub struct NurbsCurve {
    pub control_points: Vec<[f64; 3]>,
    pub weights: Vec<f64>,
    pub knot_vector: Vec<f64>,
    pub degree: usize,
}

A Non-Uniform Rational B-Spline (NURBS) curve.

Fields

control_points: Vec<[f64; 3]>

Control points.

weights: Vec<f64>

Rational weights, one per control point.

knot_vector: Vec<f64>

Knot vector.

degree: usize

Degree of the B-spline basis.

Implementations

impl NurbsCurve

pub fn new( degree: usize, control_points: Vec<[f64; 3]>, weights: Vec<f64>, knot_vector: Vec<f64>, ) -> Self

Construct a NURBS curve.

pub fn b_spline_basis(i: usize, p: usize, t: f64, knots: &[f64]) -> f64

Cox–de Boor B-spline basis function N_{i,p}(t).

pub fn find_span(n: usize, p: usize, t: f64, knots: &[f64]) -> usize

Find the knot span index for parameter t using binary search.

Returns index k such that knots[k] <= t < knots[k+1].

pub fn evaluate(&self, t: f64) -> [f64; 3]

Evaluate the NURBS curve at parameter t.

Uses the rational formula: Σ(w_i · N_{i,p}(t) · P_i) / Σ(w_i · N_{i,p}(t)).

impl NurbsCurve

pub fn arc_length(&self, t_start: f64, t_end: f64, n_samples: usize) -> f64

Compute the arc length of the NURBS curve over [t_start, t_end] using n_samples trapezoid-rule segments.

pub fn arc_length_table(&self, n_samples: usize) -> (Vec<f64>, Vec<f64>)

Build an arc-length reparametrization table with n_samples samples.

Returns a pair of Vecf64—(arc_lengths, params)— wherearc_lengths[i]is the arc length at parameterparams[i]`. The parameter range is taken from the knot vector.

pub fn compute_arc_length_reparametrize( &self, n_table: usize, n_out: usize, ) -> Vec<[f64; 3]>

Reparametrize by arc length: sample the curve at n_out equally-spaced arc-length values and return the corresponding 3-D positions.

Internally builds an arc-length table with n_table entries.