Modify

verb.eval.Modify

CLASS

Source code

Modify contains many fundamental algorithms for working with NURBS. These include algorithms for:

knot insertion
knot refinement
decomposition into bezier's
degree elevation
reparameterization

Many of these algorithsm owe their implementation to Piegl & Tiller's, "The NURBS Book"

curveReverse

STATIC METHOD

Source code

curveReverse(curve : NurbsCurveData) : NurbsCurveData

Reverses the parameterization of a NURBS curve. The domain is unaffected.

params

A NURBS curve to be reversed

returns

A new NURBS curve with a reversed parameterization

surfaceReverse

STATIC METHOD

Source code

surfaceReverse(surface : NurbsSurfaceData, useV : Bool) : NurbsSurfaceData

Reverse the parameterization of a NURBS surface in the specified direction. The domain is unaffected.

params

A NURBS surface to be reversed
Whether to use the U direction or V direction

returns

A new NURBS surface with a reversed parameterization in the given direction

knotsReverse

STATIC METHOD

Source code

knotsReverse(knots : KnotArray) : KnotArray

Reverse a knot vector

params

An array of knots

returns

The reversed array of knots

unifyCurveKnotVectors

STATIC METHOD

Source code

unifyCurveKnotVectors(curves : Array<NurbsCurveData>) : Array<NurbsCurveData>

Unify the knot vectors of a collection of NURBS curves. This can be used, for example, is used for lofting between curves.

params

An array of NURBS curves

returns

A collection of NURBS curves, all with the same knot vector

curveElevateDegree

STATIC METHOD

Source code

curveElevateDegree(curve : NurbsCurveData, finalDegree : Int) : NurbsCurveData

Elevate the degree of a NURBS curve

params

The curve to elevate
The expected final degree

returns

The NURBS curve after degree elevation - if the supplied degree is <= the curve is returned unmodified

rationalSurfaceTransform

STATIC METHOD

Source code

rationalSurfaceTransform(surface : NurbsSurfaceData, mat : Matrix) : NurbsSurfaceData

Transform a NURBS surface using a matrix

params

The surface to transform
The matrix to use for the transform - the dimensions should be the dimension of the surface + 1 in both directions

returns

A new NURBS surface after transformation

rationalCurveTransform

STATIC METHOD

Source code

rationalCurveTransform(curve : NurbsCurveData, mat : Matrix) : NurbsCurveData

Transform a NURBS curve using a matrix

params

The curve to transform
The matrix to use for the transform - the dimensions should be the dimension of the curve + 1 in both directions

returns

A new NURBS surface after transformation

surfaceKnotRefine

STATIC METHOD

Source code

surfaceKnotRefine(surface : NurbsSurfaceData, knotsToInsert : Array<Float>, useV : Bool) : NurbsSurfaceData

Perform knot refinement on a NURBS surface by inserting knots at various parameters

params

The surface to insert the knots into
The knots to insert - an array of parameter positions within the surface domain
Whether to insert in the U direction or V direction of the surface

returns

A new NURBS surface with the knots inserted

decomposeCurveIntoBeziers

STATIC METHOD

Source code

decomposeCurveIntoBeziers(curve : NurbsCurveData) : Array<NurbsCurveData>

Decompose a NURBS curve into a collection of bezier's. Useful as each bezier fits into it's convex hull. This is a useful starting point for intersection, closest point, divide & conquer algorithms

params

NurbsCurveData object representing the curve

returns

Array of NurbsCurveData objects, defined by degree, knots, and control points

curveKnotRefine

STATIC METHOD

Source code

curveKnotRefine(curve : NurbsCurveData, knotsToInsert : Array<Float>) : NurbsCurveData

Insert a collection of knots on a curve

Corresponds to Algorithm A5.4 (Piegl & Tiller)

params

NurbsCurveData object representing the curve
array of knots to insert

returns

NurbsCurveData object representing the curve

curveKnotInsert

STATIC METHOD

Source code

curveKnotInsert(curve : NurbsCurveData, u : Float, r : Int) : NurbsCurveData

Insert a knot along a rational curve. Note that this algorithm only works for r + s <= degree, where s is the initial multiplicity (number of duplicates) of the knot.

Corresponds to algorithm A5.1 (Piegl & Tiller)

Use the curveKnotRefine for applications like curve splitting.

params

integer degree
array of nondecreasing knot values
array of control points
parameter at which to insert the knot
number of times to insert the knot

returns

Object the new curve, defined by knots and controlPoints