module-NURBSUtils.html.md 4.2 KB
NURBSUtils
Import
NURBSUtils is an addon, and must be imported explicitly, see Installation#Addons.
import * as NURBSUtils from 'three/addons/curves/NURBSUtils.js';
Methods
.calcBSplineDerivatives( p : number, U : Array., P : Array., u : number, nd : number ) : Array. (inner)
Calculates derivatives of a B-Spline. See The NURBS Book, page 93, algorithm A3.2.
p
The degree.
U
The knot vector.
P
The control points
u
The parametric point.
nd
The number of derivatives.
Returns: An array[d+1] with derivatives.
.calcBSplinePoint( p : number, U : Array., P : Array., u : number ) : Vector4 (inner)
Calculates B-Spline curve points. See The NURBS Book, page 82, algorithm A3.1.
p
The degree of the B-Spline.
U
The knot vector.
P
The control points
u
The parametric point.
Returns: The point for given u.
.calcBasisFunctionDerivatives( span : number, u : number, p : number, n : number, U : Array. ) : Array.> (inner)
Calculates basis functions derivatives. See The NURBS Book, page 72, algorithm A2.3.
span
The span in which u lies.
u
The parametric point.
p
The degree.
n
number of derivatives to calculate
U
The knot vector.
Returns: An array[n+1][p+1] with basis functions derivatives.
.calcBasisFunctions( span : number, u : number, p : number, U : Array. ) : Array. (inner)
Calculates basis functions. See The NURBS Book, page 70, algorithm A2.2.
span
The span in which u lies.
u
The parametric value.
p
The degree.
U
The knot vector.
Returns: Array[p+1] with basis functions values.
.calcKoverI( k : number, i : number ) : number (inner)
Calculates "K over I".
k
The K value.
i
The I value.
Returns: k!/(i!(k-i)!)
.calcNURBSDerivatives( p : number, U : Array., P : Array., u : number, nd : number ) : Array. (inner)
Calculates NURBS curve derivatives. See The NURBS Book, page 127, algorithm A4.2.
p
The degree.
U
The knot vector.
P
The control points in homogeneous space.
u
The parametric point.
nd
The number of derivatives.
Returns: array with derivatives for rational curve.
.calcRationalCurveDerivatives( Pders : Array. ) : Array. (inner)
Calculates derivatives (0-nd) of rational curve. See The NURBS Book, page 127, algorithm A4.2.
Pders
Array with derivatives.
Returns: An array with derivatives for rational curve.
.calcSurfacePoint( p : number, q : number, U : Array., V : Array., P : Array.>, u : number, v : number, target : Vector3 ) (inner)
Calculates a rational B-Spline surface point. See The NURBS Book, page 134, algorithm A4.3.
p
The first degree of B-Spline surface.
q
The second degree of B-Spline surface.
U
The first knot vector.
V
The second knot vector.
P
The control points in homogeneous space.
u
The first parametric point.
v
The second parametric point.
target
The target vector.
.calcVolumePoint( p : number, q : number, r : number, U : Array., V : Array., W : Array., P : Array.>>, u : number, v : number, w : number, target : Vector3 ) (inner)
Calculates a rational B-Spline volume point. See The NURBS Book, page 134, algorithm A4.3.
p
The first degree of B-Spline surface.
q
The second degree of B-Spline surface.
r
The third degree of B-Spline surface.
U
The first knot vector.
V
The second knot vector.
W
The third knot vector.
P
The control points in homogeneous space.
u
The first parametric point.
v
The second parametric point.
w
The third parametric point.
target
The target vector.
.findSpan( p : number, u : number, U : Array. ) : number (inner)
Finds knot vector span.
p
The degree.
u
The parametric value.
U
The knot vector.
Returns: The span.