Create a C2 non-rational uniform cubic NURBS approximation of a swept helix or spiral.

Namespace: Rhino.Geometry
Assembly: RhinoCommon (in RhinoCommon.dll) Version: Rhino 6.0

C#

public static NurbsCurve CreateSpiral(
	Curve railCurve,
	double t0,
	double t1,
	Point3d radiusPoint,
	double pitch,
	double turnCount,
	double radius0,
	double radius1,
	int pointsPerTurn
)

VB

Public Shared Function CreateSpiral ( 
	railCurve As Curve,
	t0 As Double,
	t1 As Double,
	radiusPoint As Point3d,
	pitch As Double,
	turnCount As Double,
	radius0 As Double,
	radius1 As Double,
	pointsPerTurn As Integer
) As NurbsCurve

railCurve

Type: Rhino.Geometry.Curve
The rail curve.

t0

Type: System.Double
Starting portion of rail curve's domain to sweep along.

t1

Type: System.Double
Ending portion of rail curve's domain to sweep along.

radiusPoint

Type: Rhino.Geometry.Point3d
Point used only to get a vector that is perpedicular to the axis. In particular, this vector must not be (anti)parallel to the axis vector.

pitch

Type: System.Double
The pitch. Positive values produce counter-clockwise orientation, negative values produce clockwise orientation.

turnCount

Type: System.Double
The turn count. If != 0, then the resulting helix will have this many turns. If = 0, then pitch must be != 0 and the approximate distance between turns will be set to pitch. Positive values produce counter-clockwise orientation, negitive values produce clockwise orientation.

radius0

Type: System.Double
The starting radius. At least one radii must benonzero. Negative values are allowed.

radius1

Type: System.Double
The ending radius. At least ont radii must be nonzero. Negative values are allowed.

pointsPerTurn

Type: System.Int32
Number of points to intepolate per turn. Must be greater than 4. When in doubt, use 12.

Type: NurbsCurve
NurbsCurve on success, null on failure.

Supported in: 6.0.16224.21491, 5D58w

NurbsCurve Class
CreateSpiral Overload
Rhino.Geometry Namespace