Interface ICurve

Interface implemented by one-dimensional geometric objects (eg. line, circle, bspline etc.). The curve may be open or closed.

Namespace: CADability.GeoObject

Assembly: CADability.dll

Syntax

public interface ICurve

Properties

Description

Returns a description of the curve, used in labels of the controlcenter.

Declaration

string Description { get; }

Property Value

Type	Description
System.String

EndDirection

The direction of the curve at the endpoint. If the curve is closed, this is the direction where the parameter is 1.0.

Declaration

GeoVector EndDirection { get; }

Property Value

Type	Description
GeoVector

EndPoint

The endpoint of the curve. If the curve is closed, this is the point where the parameter is 1.0.

Declaration

GeoPoint EndPoint { get; set; }

Property Value

Type	Description
GeoPoint

IsClosed

Determines, whether the curve is closed or open.

Declaration

bool IsClosed { get; }

Property Value

Type	Description
System.Boolean

IsComposed

Returns true, if the curve is composed of other curves. Paths and Polylines are composed curves.

Declaration

bool IsComposed { get; }

Property Value

Type	Description
System.Boolean

IsSingular

Determines, whether this curve is singular, i.e. it is only a point, returns the same value for each parameter

Declaration

bool IsSingular { get; }

Property Value

Type	Description
System.Boolean

Length

Returns the length of the curve.

Declaration

double Length { get; }

Property Value

Type	Description
System.Double

StartDirection

The direction of the curve at the start-point. If the curve is closed, this is the direction where the parameter is 0.0.

Declaration

GeoVector StartDirection { get; }

Property Value

Type	Description
GeoVector

StartPoint

The start-point of the curve. If the curve is closed, this is the point where the parameter is 0.0.

Declaration

GeoPoint StartPoint { get; set; }

Property Value

Type	Description
GeoPoint

SubCurves

Returns subcurves of composed curves. Paths and Polylines are composed curves.

Declaration

ICurve[] SubCurves { get; }

Property Value

Type	Description
ICurve[]

Methods

Approximate(Boolean, Double)

Returns a Path or a Polyline that approximates the curve with lines or lines and arcs.

Declaration

ICurve Approximate(bool linesOnly, double maxError)

Parameters

Type	Name	Description
System.Boolean	linesOnly	true: no arcs, only lines
System.Double	maxError	Maximum derivation from the exact curve

Returns

Type	Description
ICurve	The Approximation

Clone()

Returns an identical copy of this curve

Declaration

ICurve Clone()

Returns

Type	Description
ICurve

CloneModified(ModOp)

Returns a modified copy of this curve

Declaration

ICurve CloneModified(ModOp m)

Parameters

Type	Name	Description
ModOp	m	modification

Returns

Type	Description
ICurve	modified copy

DirectionAt(Double)

Returns the direction of the curve at a specified point. The parameter prosition of the start-point is 0.0, the parameter position of the endpoint is 1.0. Directions of a position outside this interval may be undefined.

Declaration

GeoVector DirectionAt(double Position)

Parameters

Type	Name	Description
System.Double	Position	Position on the curve

Returns

Type	Description
GeoVector	The requested direction

DistanceTo(GeoPoint)

Returns the minimal distance of point p to the curve.

Declaration

double DistanceTo(GeoPoint p)

Parameters

Type	Name	Description
GeoPoint	p

Returns

Type	Description
System.Double

GetExtent()

Returns the bounging cube for this curve

Declaration

BoundingCube GetExtent()

Returns

Type	Description
BoundingCube	The cube bounding this curve

GetExtrema(GeoVector)

Returns points of the curve (parameter values between 0.0 and 1.0) where the curve is tangential to a plane defined by the normal vector direction. These points are minima or maxima in that direction.

Declaration

double[] GetExtrema(GeoVector direction)

Parameters

Type	Name	Description
GeoVector	direction	Direction for the extrema

Returns

Type	Description
System.Double[]	Positions of the extrema, if any

GetPlanarState()

Determins the state of the curve in space. A curve may be either Planar (e.g. a cicle), NonPlanar (e.g. a polyline with vertices that dont shear a common plane) or UnderDetermined (e.g. a line defines a sheaf of planes (Ebenenbüschel))

Declaration

PlanarState GetPlanarState()

Returns

Type	Description
PlanarState

GetPlane()

Determins the plane in which the curve resides. Throws CurveException if the curve's PlanarState is NonPlanar or UnderDetermined.

Declaration

Plane GetPlane()

Returns

Type	Description
Plane	The plane

GetPlaneIntersection(Plane)

Returns the parameters of the intersection points with the provided plane

Declaration

double[] GetPlaneIntersection(Plane plane)

Parameters

Type	Name	Description
Plane	plane	To intersect with

Returns

Type	Description
System.Double[]	Intersection parameters, may be empty

GetProjectedCurve(Plane)

Orthogonally projects this curve into the given plane. Returns the 2D curve in the coordinate system of the given plane.

Declaration

ICurve2D GetProjectedCurve(Plane p)

Parameters

Type	Name	Description
Plane	p	The plane this curve will be projected on

Returns

Type	Description
ICurve2D	The 2D curve in the given plane

GetSavePositions()

Returns some positions (parameter values between 0.0 and 1.0) that can savely be used for Approximation purposes Usually not used by external applications

Declaration

double[] GetSavePositions()

Returns

Type	Description
System.Double[]

GetSelfIntersections()

Returns the self intersection position of this curve. The returned array contains pairs of parameter values. Each intersectionpoint corresponds to two parameters.

Declaration

double[] GetSelfIntersections()

Returns

Type	Description
System.Double[]	Parameters of the intersection points

HitTest(BoundingCube)

Determins whether this curve interferes with the provided cube.

Declaration

bool HitTest(BoundingCube cube)

Parameters

Type	Name	Description
BoundingCube	cube	Cube to check interference with

Returns

Type	Description
System.Boolean	True, if curve and cube interfere

IsInPlane(Plane)

Determines whether the curve resides in the given plane.

Declaration

bool IsInPlane(Plane p)

Parameters

Type	Name	Description
Plane	p	The plane for the test

Returns

Type	Description
System.Boolean	true, when the curve resides in the plane

ParameterToPosition(Double)

convert the parameter, which is in a natural system (0..2*pi for circle, first knot to last knot for bspline) to the 0..1 normalized position

Declaration

double ParameterToPosition(double parameter)

Parameters

Type	Name	Description
System.Double	parameter

Returns

Type	Description
System.Double	the position, 0..1 when inside the bounds

PointAt(Double)

Returns the point of the given position. The parameter prosition of the start-point is 0.0, the parameter position of the endpoint is 1.0. Points of a position outside this interval may be undefined. The correlatioon between the parameter Position and the resulting point may be not linear.

Declaration

GeoPoint PointAt(double Position)

Parameters

Type	Name	Description
System.Double	Position	Position on the curve

Returns

Type	Description
GeoPoint	The requested point

PositionAtLength(Double)

Returns the parameter of the point at the given position. The position must be in the interval [0, Length]. The correlatioon between the parameter Position and the resulting position is linear. The result is usually used for PointAt(Double) or DirectionAt(Double).

Declaration

double PositionAtLength(double position)

Parameters

Type	Name	Description
System.Double	position	Position on the curve

Returns

Type	Description
System.Double	The requested position

PositionOf(GeoPoint)

Returns the parametric position of the point on the curve. This function is invers to DirectionAt(Double). If the given point is not on the curve, the result is the position of a point on the curve, that is close to the given point, but not necessary of the closest point.

Declaration

double PositionOf(GeoPoint p)

Parameters

Type	Name	Description
GeoPoint	p	Point, whos position is requested

Returns

Type	Description
System.Double	the requested position

PositionOf(GeoPoint, Plane)

Similar to the PointAt(Double) method. Returns the same result, if the point is on the curve. If the point is not on the curve the problem is looked at in the given plane. i.e. the closest point on the projected 2d curve from the projected 2d point is used.

Declaration

double PositionOf(GeoPoint p, Plane pl)

Parameters

Type	Name	Description
GeoPoint	p	Point, whos position is requested
Plane	pl	Plane for the computation of the closest point

Returns

Type	Description
System.Double	the requested position

PositionOf(GeoPoint, Double)

Similar to PositionOf(GeoPoint). If the point is not on the curve and there are several solutions then the solution closest to the parameter prefer will be returned.

Declaration

double PositionOf(GeoPoint p, double prefer)

Parameters

Type	Name	Description
GeoPoint	p	Point, whos position is requested
System.Double	prefer	preferable solution close to this value

Returns

Type	Description
System.Double	the requested position

PositionToParameter(Double)

convert the position (which is in the 0..1 interval) to the natural parameter value

Declaration

double PositionToParameter(double position)

Parameters

Type	Name	Description
System.Double	position

Returns

Type	Description
System.Double

Reverse()

Reverses the direction of the curve.

Declaration

void Reverse()

SameGeometry(ICurve, Double)

Returns true, if this curve and the provided curve describe the same curve in space (maybe opposite direction)

Declaration

bool SameGeometry(ICurve other, double precision)

Parameters

Type	Name	Description
ICurve	other	The curve to be compared with
System.Double	precision	The required precision

Returns

Type	Description
System.Boolean	true, if geometrically equal

Split(Double)

Splits the curve at the given position. The position must be in the interval 0..1 and the curve must not be closed. For closed curves Split(Double, Double).

Declaration

ICurve[] Split(double Position)

Parameters

Type	Name	Description
System.Double	Position	Where to split

Returns

Type	Description
ICurve[]	the splitted curve(s)

Split(Double, Double)

Splits the closed curve into two open curves at the given positions.

Declaration

ICurve[] Split(double Position1, double Position2)

Parameters

Type	Name	Description
System.Double	Position1	first Position
System.Double	Position2	second Position

Returns

Type	Description
ICurve[]	the splitted curve(s)

TangentPosition(GeoVector)

Returns a list of positions where the curve has the same or opposite direction as the given direction. Mainly used for visualisation purposes. If there are no such points (which is true in most cases) An empty array should be returned.

Declaration

double[] TangentPosition(GeoVector direction)

Parameters

Type	Name	Description
GeoVector	direction

Returns

Type	Description
System.Double[]

Trim(Double, Double)

Modifies start and endpoint of this curve. StartPos must be less than EndPos. if StartPos is less than 0.0 or EndPos greater than 1.0 this only works for lines and (circular or elliptical) arcs.

Declaration

void Trim(double StartPos, double EndPos)

Parameters

Type	Name	Description
System.Double	StartPos	New start position
System.Double	EndPos	New end position

TryPointDeriv2At(Double, out GeoPoint, out GeoVector, out GeoVector)

Tries to get the point and the first and second derivative of the curve at the specified position. (0..1) Some curves do not implement the second derivative and hence will return false.

Declaration

bool TryPointDeriv2At(double position, out GeoPoint point, out GeoVector deriv1, out GeoVector deriv2)

Parameters

Type	Name	Description
System.Double	position	Position where to calculate point and derivatives
GeoPoint	point	The point at the required position
GeoVector	deriv1	The first derivative at the provided parameter
GeoVector	deriv2	The second derivative at the provided parameter

Returns

Type	Description
System.Boolean