Struct BsplineSurface 

pub struct BsplineSurface {
    pub control_net: Vec<Vec<[f64; 3]>>,
    pub u_knots: Vec<f64>,
    pub v_knots: Vec<f64>,
    pub degree_u: usize,
    pub degree_v: usize,
}

A tensor-product B-spline surface defined by a rectangular control net.

control_net[i][j] is the (i, j) control point. Knot vectors in each parameter direction are stored separately.

Fields

control_net: Vec<Vec<[f64; 3]>>

Control net — outer index u, inner index v.

u_knots: Vec<f64>

Knot vector in the u direction.

v_knots: Vec<f64>

Knot vector in the v direction.

degree_u: usize

Polynomial degree in u.

degree_v: usize

Polynomial degree in v.

Implementations

impl BsplineSurface

pub fn new( control_net: Vec<Vec<[f64; 3]>>, u_knots: Vec<f64>, v_knots: Vec<f64>, degree_u: usize, degree_v: usize, ) -> Self

Construct a BsplineSurface.

pub fn eval(&self, u: f64, v: f64) -> [f64; 3]

Evaluate the surface at parameter (u, v) using tensor-product de Boor.

pub fn compute_curvature(&self, u: f64, v: f64) -> (f64, f64)

Compute Gaussian curvature K and mean curvature H at (u, v).

Uses the first and second fundamental forms computed via finite differences of the surface position.

Returns (K, H). Both values may be NaN at degenerate points.

pub fn refine_knots(&self, new_u_knots: &[f64], new_v_knots: &[f64]) -> Self

H-refinement via knot insertion in both parameter directions.

new_u_knots and new_v_knots are sorted lists of knot values to insert (repeated insertions are handled by the Boehm algorithm).

Returns a new BsplineSurface with the refined control net.