Curve Methods 
The Curve type exposes the following members.
Name  Description  

ChangeClosedCurveSeam 
If this curve is closed, then modify it so that the start/end point is at curve parameter t.
 
ChangeDimension 
Changes the dimension of a curve.
 
ClosedCurveOrientation(Plane) 
Determines the orientation (counterclockwise or clockwise) of a closed planar curve in a given plane.
Only works with simple (no self intersections) closed planar curves.
 
ClosedCurveOrientation(Transform) 
Determines the orientation (counterclockwise or clockwise) of a closed planar curve.
Only works with simple (no self intersections) closed planar curves.
 
ClosedCurveOrientation(Vector3d) 
Determines the orientation (counterclockwise or clockwise) of a closed planar curve in a given plane.
Only works with simple (no self intersections) closed planar curves.
 
ClosestPoint(Point3d, Double) 
Finds parameter of the point on a curve that is closest to testPoint.
If the maximumDistance parameter is > 0, then only points whose distance
to the given point is <= maximumDistance will be returned. Using a
positive value of maximumDistance can substantially speed up the search.
 
ClosestPoint(Point3d, Double, Double) 
Finds the parameter of the point on a curve that is closest to testPoint.
If the maximumDistance parameter is > 0, then only points whose distance
to the given point is <= maximumDistance will be returned. Using a
positive value of maximumDistance can substantially speed up the search.
 
ClosestPoints(Curve, Point3d, Point3d) 
Gets closest points between this and another curves.
 
ClosestPoints(IEnumerableGeometryBase, Point3d, Point3d, Int32) 
Finds the object (and the closest point in that object) that is closest to
this curve. Breps, surfaces, curves and point clouds are examples of objects that can be passed to this function.  
ClosestPoints(IEnumerableGeometryBase, Point3d, Point3d, Int32, Double) 
Finds the object (and the closest point in that object) that is closest to
this curve. Breps, surfaces, curves and point clouds are examples of objects that can be passed to this function.  
ComponentIndex 
If this piece of geometry is a component in something larger, like a BrepEdge
in a Brep, then this function returns the component index.
(Inherited from GeometryBase.)  
ConstructConstObject 
Assigns a parent object and a subobject index to this.
(Inherited from CommonObject.)  
Contains(Point3d) 
Computes the relationship between a point and a closed curve region.
This curve must be closed or the return value will be Unset.
Both curve and point are projected to the World XY plane.
 
Contains(Point3d, Plane) 
Computes the relationship between a point and a closed curve region.
This curve must be closed or the return value will be Unset.
 
Contains(Point3d, Plane, Double) 
Computes the relationship between a point and a closed curve region.
This curve must be closed or the return value will be Unset.
 
CreateBlendCurve(Curve, Curve, BlendContinuity) 
Create a Blend curve between two existing curves.
 
CreateBlendCurve(Curve, Curve, BlendContinuity, Double, Double) 
Create a Blend curve between two existing curves.
 
CreateBlendCurve(Curve, Double, Boolean, BlendContinuity, Curve, Double, Boolean, BlendContinuity) 
Makes a curve blend between 2 curves at the parameters specified
with the directions and continuities specified
 
CreateBooleanDifference(Curve, Curve) 
Calculates the boolean difference between two closed, planar curves.
Note, curves must be coplanar.
 
CreateBooleanDifference(Curve, IEnumerableCurve) 
Calculates the boolean difference between a closed planar curve, and a list of closed planar curves.
Note, curves must be coplanar.
 
CreateBooleanIntersection 
Calculates the boolean intersection of two closed, planar curves.
Note, curves must be coplanar.
 
CreateBooleanUnion 
Calculates the boolean union of two or more closed, planar curves.
Note, curves must be coplanar.
 
CreateControlPointCurve(IEnumerablePoint3d) 
Constructs a controlpoint of degree=3 (or less).
 
CreateControlPointCurve(IEnumerablePoint3d, Int32) 
Constructs a curve from a set of controlpoint locations.
 
CreateFillet 
Computes the fillet arc for a curve filleting operation.
 
CreateFilletCurves 
Creates a tangent arc between two curves and trims or extends the curves to the arc.
 
CreateInterpolatedCurve(IEnumerablePoint3d, Int32) 
Interpolates a sequence of points. Used by InterpCurve Command
This routine works best when degree=3.
 
CreateInterpolatedCurve(IEnumerablePoint3d, Int32, CurveKnotStyle) 
Interpolates a sequence of points. Used by InterpCurve Command
This routine works best when degree=3.
 
CreateInterpolatedCurve(IEnumerablePoint3d, Int32, CurveKnotStyle, Vector3d, Vector3d) 
Interpolates a sequence of points. Used by InterpCurve Command
This routine works best when degree=3.
 
CreateMeanCurve(Curve, Curve) 
Constructs a mean, or average, curve from two curves.
 
CreateMeanCurve(Curve, Curve, Double) 
Constructs a mean, or average, curve from two curves.
 
CreateTweenCurves 
Creates curves between two open or closed input curves. Uses the control points of the curves for finding tween curves.
That means the first control point of first curve is matched to first control point of the second curve and so on.
There is no matching of curves direction. Caller must match input curves direction before calling the function.
 
CreateTweenCurvesWithMatching 
Creates curves between two open or closed input curves. Make the structure of input curves compatible if needed.
Refits the input curves to have the same structure. The resulting curves are usually more complex than input unless
input curves are compatible and no refit is needed. There is no matching of curves direction.
Caller must match input curves direction before calling the function.
 
CreateTweenCurvesWithSampling 
Creates curves between two open or closed input curves. Use sample points method to make curves compatible.
This is how the algorithm workd: Divides the two curves into an equal number of points, finds the midpoint between the
corresponding points on the curves and interpolates the tween curve through those points. There is no matching of curves
direction. Caller must match input curves direction before calling the function.
 
CurvatureAt  Evaluate the curvature vector at a curve parameter.  
DerivativeAt(Double, Int32) 
Evaluate the derivatives at the specified curve parameter.
 
DerivativeAt(Double, Int32, CurveEvaluationSide) 
Evaluate the derivatives at the specified curve parameter.
 
Dispose 
Actively reclaims unmanaged resources that this instance uses.
(Inherited from CommonObject.)  
Dispose(Boolean) 
For derived class implementers.
(Overrides CommonObjectDispose(Boolean).)This method is called with argument true when class user calls Dispose(), while with argument false when the Garbage Collector invokes the finalizer, or Finalize() method. You must reclaim all used unmanaged resources in both cases, and can use this chance to call Dispose on disposable fields if the argument is true. Also, you must call the base virtual method within your overriding method.  
DivideAsContour 
Divides this curve at fixed steps along a defined contour line.
 
DivideByCount(Int32, Boolean) 
Divide the curve into a number of equallength segments.
 
DivideByCount(Int32, Boolean, Point3d) 
Divide the curve into a number of equallength segments.
 
DivideByLength(Double, Boolean) 
Divide the curve into specific length segments.
 
DivideByLength(Double, Boolean, Point3d) 
Divide the curve into specific length segments.
 
DivideEquidistant 
Calculates 3d points on a curve where the linear distance between the points is equal.
 
DoDirectionsMatch 
Determines whether two curves travel more or less in the same direction.
 
Duplicate 
Constructs an exact duplicate of this Curve.
(Overrides GeometryBaseDuplicate.)  
DuplicateCurve 
Constructs an exact duplicate of this curve.
 
DuplicateSegments 
Polylines will be exploded into line segments. ExplodeCurves will
return the curves in topological order.
 
DuplicateShallow 
Constructs a light copy of this object. By "light", it is meant that the same
underlying data is used until something is done to attempt to change it. For example,
you could have a shallow copy of a very heavy mesh object and the same underlying
data will be used when doing things like inspecting the number of faces on the mesh.
If you modify the location of one of the mesh vertices, the shallow copy will create
a full duplicate of the underlying mesh data and the shallow copy will become a
deep copy.
(Inherited from GeometryBase.)  
EnsurePrivateCopy 
If you want to keep a copy of this class around by holding onto it in a variable after a command
completes, call EnsurePrivateCopy to make sure that this class is not tied to the document. You can
call this function as many times as you want.
(Inherited from CommonObject.)  
Equals  Determines whether the specified object is equal to the current object. (Inherited from Object.)  
Extend(Interval) 
Where possible, analytically extends curve to include the given domain.
This will not work on closed curves. The original curve will be identical to the
restriction of the resulting curve to the original curve domain.
 
Extend(Double, Double) 
Where possible, analytically extends curve to include the given domain.
This will not work on closed curves. The original curve will be identical to the
restriction of the resulting curve to the original curve domain.
 
Extend(CurveEnd, CurveExtensionStyle, Point3d) 
Extends a curve to a point.
 
Extend(CurveEnd, CurveExtensionStyle, IEnumerableGeometryBase) 
Extends a curve until it intersects a collection of objects.
 
Extend(CurveEnd, Double, CurveExtensionStyle) 
Extends a curve by a specific length.
 
ExtendByArc 
Extends a curve by an Arc until it intersects a collection of objects.
 
ExtendByLine 
Extends a curve by a line until it intersects a collection of objects.
 
ExtendOnSurface(CurveEnd, BrepFace) 
Extends a curve on a surface.
 
ExtendOnSurface(CurveEnd, Surface) 
Extends a curve on a surface.
 
Fair 
Fairs a curve object. Fair works best on degree 3 (cubic) curves. Attempts to
remove large curvature variations while limiting the geometry changes to be no
more than the specified tolerance.
 
Finalize 
Passively reclaims unmanaged resources when the class user did not explicitly call Dispose().
(Inherited from CommonObject.)  
Fit 
Fits a new curve through an existing curve.
 
FrameAt  Returns a 3d frame at a parameter.  
GetBoundingBox(Boolean) 
Boundingbox solver. Gets the world axis aligned boundingbox for the geometry.
(Inherited from GeometryBase.)  
GetBoundingBox(Plane) 
Aligned Boundingbox solver. Gets the plane aligned boundingbox.
(Inherited from GeometryBase.)  
GetBoundingBox(Transform) 
Aligned Boundingbox solver. Gets the world axis aligned boundingbox for the transformed geometry.
(Inherited from GeometryBase.)  
GetBoundingBox(Plane, Box) 
Aligned Boundingbox solver. Gets the plane aligned boundingbox.
(Inherited from GeometryBase.)  
GetCurveParameterFromNurbsFormParameter 
Convert a NURBS curve parameter to a curve parameter.
 
GetDistancesBetweenCurves 
Computes the distances between two arbitrary curves that overlap.
 
GetFilletPoints 
Finds points at which to cut a pair of curves so that a fillet of given radius can be inserted.
 
GetHashCode  Serves as the default hash function. (Inherited from Object.)  
GetLength 
Gets the length of the curve with a fractional tolerance of 1.0e8.
 
GetLength(Double)  Get the length of the curve.  
GetLength(Interval)  Get the length of a subsection of the curve with a fractional tolerance of 1e8.  
GetLength(Double, Interval)  Get the length of a subsection of the curve.  
GetNextDiscontinuity 
Searches for a derivative, tangent, or curvature discontinuity.
 
GetNurbsFormParameterFromCurveParameter  Convert a curve parameter to a NURBS curve parameter.  
GetObjectData 
Populates a System.Runtime.Serialization.SerializationInfo with the data needed to serialize the target object.
(Inherited from CommonObject.)  
GetPerpendicularFrames 
Gets a collection of perpendicular frames along the curve. Perpendicular frames
are also known as 'Zerotwisting frames' and they minimize rotation from one frame to the next.
 
GetType  Gets the Type of the current instance. (Inherited from Object.)  
GetUserString 
Gets user string from this geometry.
(Inherited from GeometryBase.)  
GetUserStrings 
Gets a copy of all (user key string, user value string) pairs attached to this geometry.
(Inherited from GeometryBase.)  
HasNurbsForm 
Does a NURBS curve representation of this curve exist?
 
IsArc 
Test a curve to see if it can be represented by an arc or circle within RhinoMath.ZeroTolerance.
 
IsArc(Double) 
Test a curve to see if it can be represented by an arc or circle within the given tolerance.
 
IsCircle 
Test a curve to see if it can be represented by a circle within RhinoMath.ZeroTolerance.
 
IsCircle(Double) 
Test a curve to see if it can be represented by a circle within the given tolerance.
 
IsClosable(Double) 
Decide if it makes sense to close off this curve by moving the endpoint
to the start based on startend gap size and length of curve as
approximated by chord defined by 6 points.
 
IsClosable(Double, Double, Double) 
Decide if it makes sense to close off this curve by moving the endpoint
to the start based on startend gap size and length of curve as
approximated by chord defined by 6 points.
 
IsContinuous 
Test continuity at a curve parameter value.
 
IsEllipse 
Test a curve to see if it can be represented by an ellipse within RhinoMath.ZeroTolerance.
 
IsEllipse(Double) 
Test a curve to see if it can be represented by an ellipse within a given tolerance.
 
IsInPlane(Plane)  Test a curve to see if it lies in a specific plane.  
IsInPlane(Plane, Double)  Test a curve to see if it lies in a specific plane.  
IsLinear 
Test a curve to see if it is linear to within RhinoMath.ZeroTolerance units (1e12).
 
IsLinear(Double) 
Test a curve to see if it is linear to within the custom tolerance.
 
IsPlanar  Test a curve for planarity.  
IsPlanar(Double)  Test a curve for planarity.  
IsPolyline 
Several types of Curve can have the form of a polyline
including a degree 1 NurbsCurve, a PolylineCurve,
and a PolyCurve all of whose segments are some form of
polyline. IsPolyline tests a curve to see if it can be
represented as a polyline.
 
IsShort(Double)  Used to quickly find short curves.  
IsShort(Double, Interval)  Used to quickly find short curves.  
IsValidWithLog 
Determines if an object is valid. Also provides a report on errors if this
object happens not to be valid.
(Inherited from CommonObject.)  
JoinCurves(IEnumerableCurve) 
Joins a collection of curve segments together.
 
JoinCurves(IEnumerableCurve, Double) 
Joins a collection of curve segments together.
 
JoinCurves(IEnumerableCurve, Double, Boolean) 
Joins a collection of curve segments together.
 
LengthParameter(Double, Double) 
Gets the parameter along the curve which coincides with a given length along the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
LengthParameter(Double, Double, Interval) 
Gets the parameter along the curve which coincides with a given length along the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
LengthParameter(Double, Double, Double) 
Gets the parameter along the curve which coincides with a given length along the curve.
 
LengthParameter(Double, Double, Double, Interval) 
Gets the parameter along the curve which coincides with a given length along the curve.
 
MakeClosed 
If IsClosed, just return true. Otherwise, decide if curve can be closed as
follows: Linear curves polylinear curves with 2 segments, Nurbs with 3 or less
control points cannot be made closed. Also, if tolerance > 0 and the gap between
start and end is larger than tolerance, curve cannot be made closed.
Adjust the curve's endpoint to match its start point.
 
MakeDeformable 
If possible, converts the object into a form that can be accurately modified
with "squishy" transformations like projections, shears, an nonuniform scaling.
(Inherited from GeometryBase.)  
MakeEndsMeet 
Makes adjustments to the ends of one or both input curves so that they meet at a point.
 
MemberwiseClone  Creates a shallow copy of the current Object. (Inherited from Object.)  
MemoryEstimate 
Computes an estimate of the number of bytes that this object is using in memory.
(Inherited from GeometryBase.)  
NonConstOperation 
For derived classes implementers.
(Overrides CommonObjectNonConstOperation.)Defines the necessary implementation to free the instance from being const.  
NormalizedLengthParameter(Double, Double) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
NormalizedLengthParameter(Double, Double, Interval) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
NormalizedLengthParameter(Double, Double, Double) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
 
NormalizedLengthParameter(Double, Double, Double, Interval) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
 
NormalizedLengthParameters(Double, Double) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
NormalizedLengthParameters(Double, Double, Interval) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
A fractional tolerance of 1e8 is used in this version of the function.
 
NormalizedLengthParameters(Double, Double, Double) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
 
NormalizedLengthParameters(Double, Double, Double, Interval) 
Input the parameter of the point on the curve that is a prescribed arc length from the start of the curve.
 
Offset(Plane, Double, Double, CurveOffsetCornerStyle) 
Offsets this curve. If you have a nice offset, then there will be one entry in
the array. If the original curve had kinks or the offset curve had self
intersections, you will get multiple segments in the offset_curves[] array.
 
Offset(Point3d, Vector3d, Double, Double, CurveOffsetCornerStyle) 
Offsets this curve. If you have a nice offset, then there will be one entry in
the array. If the original curve had kinks or the offset curve had self
intersections, you will get multiple segments in the offset_curves[] array.
 
OffsetNormalToSurface 
Finds a curve by offsetting an existing curve normal to a surface.
The caller is responsible for ensuring that the curve lies on the input surface.
 
OffsetOnSurface(BrepFace, Point2d, Double) 
Offset a curve on a brep face surface. This curve must lie on the surface.
This overload allows to specify a surface point at which the offset will pass.  
OffsetOnSurface(BrepFace, Double, Double) 
Offset this curve on a brep face surface. This curve must lie on the surface.
 
OffsetOnSurface(Surface, Point2d, Double) 
Offset a curve on a surface. This curve must lie on the surface.
This overload allows to specify a surface point at which the offset will pass.  
OffsetOnSurface(Surface, Double, Double) 
Offset a curve on a surface. This curve must lie on the surface.
 
OffsetOnSurface(BrepFace, Double, Double, Double) 
Offset a curve on a brep face surface. This curve must lie on the surface.
This overload allows to specify different offsets for different curve parameters.  
OffsetOnSurface(Surface, Double, Double, Double) 
Offset this curve on a surface. This curve must lie on the surface.
This overload allows to specify different offsets for different curve parameters.  
OnSwitchToNonConst 
Is called when a nonconst operation occurs.
(Inherited from GeometryBase.)  
PerpendicularFrameAt 
Return a 3d frame at a parameter. This is slightly different than FrameAt in
that the frame is computed in a way so there is minimal rotation from one
frame to the next.
 
PlanarClosedCurveRelationship 
Determines whether two coplanar simple closed curves are disjoint or intersect;
otherwise, if the regions have a containment relationship, discovers
which curve encloses the other.
 
PlanarCurveCollision 
Determines if two coplanar curves collide (intersect).
 
PointAt  Evaluates point at a curve parameter.  
PointAtLength 
Gets a point at a certain length along the curve. The length must be
nonnegative and less than or equal to the length of the curve.
Lengths will not be wrapped when the curve is closed or periodic.
 
PointAtNormalizedLength 
Gets a point at a certain normalized length along the curve. The length must be
between or including 0.0 and 1.0, where 0.0 equals the start of the curve and
1.0 equals the end of the curve.
 
ProjectToBrep(Curve, Brep, Vector3d, Double) 
Projects a Curve onto a Brep along a given direction.
 
ProjectToBrep(Curve, IEnumerableBrep, Vector3d, Double) 
Projects a Curve onto a collection of Breps along a given direction.
 
ProjectToBrep(IEnumerableCurve, IEnumerableBrep, Vector3d, Double) 
Projects a collection of Curves onto a collection of Breps along a given direction.
 
ProjectToBrep(Curve, IEnumerableBrep, Vector3d, Double, Int32) 
Projects a Curve onto a collection of Breps along a given direction.
 
ProjectToBrep(IEnumerableCurve, IEnumerableBrep, Vector3d, Double, Int32, Int32) 
Projects a collection of Curves onto a collection of Breps along a given direction.
 
ProjectToMesh(Curve, Mesh, Vector3d, Double) 
Projects a curve to a mesh using a direction and tolerance.
 
ProjectToMesh(Curve, IEnumerableMesh, Vector3d, Double) 
Projects a curve to a set of meshes using a direction and tolerance.
 
ProjectToMesh(IEnumerableCurve, IEnumerableMesh, Vector3d, Double) 
Projects a curve to a set of meshes using a direction and tolerance.
 
ProjectToPlane 
Constructs a curve by projecting an existing curve to a plane.
 
PullToBrepFace(BrepFace, Double) 
Pulls this curve to a brep face and returns the result of that operation.
 
PullToBrepFace(Curve, BrepFace, Double) 
Pull a curve to a BrepFace using closest point projection.
 
PullToMesh 
Makes a polyline approximation of the curve and gets the closest point on the mesh for each point on the curve.
Then it "connects the points" so that you have a polyline on the mesh.
 
Rebuild 
Rebuild a curve with a specific point count.
 
RemoveShortSegments 
Looks for segments that are shorter than tolerance that can be removed.
Does not change the domain, but it will change the relative parameterization.
 
Reverse 
Reverses the direction of the curve.
 
Rotate 
Rotates the object about the specified axis. A positive rotation
angle results in a counterclockwise rotation about the axis (right hand rule).
(Inherited from GeometryBase.)  
Scale 
Scales the object by the specified factor. The scale is centered at the origin.
(Inherited from GeometryBase.)  
SetEndPoint  Forces the curve to end at a specified point.
Not all curve types support this operation.  
SetStartPoint  Forces the curve to start at a specified point.
Not all curve types support this operation.  
SetUserString 
Attach a user string (key,value combination) to this geometry.
(Inherited from GeometryBase.)  
Simplify 
Returns a geometrically equivalent PolyCurve.
The PolyCurve has the following properties 1. All the PolyCurve segments are LineCurve, PolylineCurve, ArcCurve, or NurbsCurve. 2. The Nurbs Curves segments do not have fully multiple interior knots. 3. Rational Nurbs curves do not have constant weights. 4. Any segment for which IsLinear() or IsArc() is true is a Line, Polyline segment, or an Arc. 5. Adjacent Colinear or Cocircular segments are combined. 6. Segments that meet with G1continuity have there ends tuned up so that they meet with G1continuity to within machine precision.  
SimplifyEnd 
Same as SimplifyCurve, but simplifies only the last two segments at "side" end.
 
SpanDomain 
Get the domain of the curve span with the given index.
Use the SpanCount property to test how many spans there are.
 
Split(IEnumerableDouble) 
Splits (divides) the curve at a series of specified parameters.
The parameter must be in the interior of the curve's domain.
 
Split(Double) 
Splits (divides) the curve at the specified parameter.
The parameter must be in the interior of the curve's domain.
 
Split(Brep, Double) 
Splits a curve into pieces using a polysurface.
 
Split(Surface, Double) 
Splits a curve into pieces using a surface.
 
TangentAt  Evaluates the unit tangent vector at a curve parameter.  
ToNurbsCurve 
Constructs a NURBS curve representation of this curve.
 
ToNurbsCurve(Interval) 
Constructs a NURBS curve representation of this curve.
 
ToPolyline(Int32, Int32, Double, Double, Double, Double, Double, Double, Boolean) 
Gets a polyline approximation of a curve.
 
ToPolyline(Int32, Int32, Double, Double, Double, Double, Double, Double, Boolean, Interval) 
Gets a polyline approximation of a curve.
 
ToString  Returns a string that represents the current object. (Inherited from Object.)  
Transform 
Transforms the geometry. If the input Transform has a SimilarityType of
OrientationReversing, you may want to consider flipping the transformed
geometry after calling this function when it makes sense. For example,
you may want to call Flip() on a Brep after transforming it.
(Inherited from GeometryBase.)  
Translate(Vector3d)  Translates the object along the specified vector. (Inherited from GeometryBase.)  
Translate(Double, Double, Double)  Translates the object along the specified vector. (Inherited from GeometryBase.)  
Trim(Interval) 
Removes portions of the curve outside the specified interval.
 
Trim(Double, Double) 
Removes portions of the curve outside the specified interval.
 
Trim(CurveEnd, Double) 
Shortens a curve by a given length
 
TryGetArc(Arc) 
Try to convert this curve into an Arc using RhinoMath.ZeroTolerance.
 
TryGetArc(Arc, Double) 
Try to convert this curve into an Arc using a custom tolerance.
 
TryGetArc(Plane, Arc) 
Try to convert this curve into an Arc using RhinoMath.ZeroTolerance.
 
TryGetArc(Plane, Arc, Double) 
Try to convert this curve into an Arc using a custom tolerance.
 
TryGetCircle(Circle) 
Try to convert this curve into a circle using RhinoMath.ZeroTolerance.
 
TryGetCircle(Circle, Double) 
Try to convert this curve into a Circle using a custom tolerance.
 
TryGetEllipse(Ellipse) 
Try to convert this curve into an Ellipse within RhinoMath.ZeroTolerance.
 
TryGetEllipse(Ellipse, Double) 
Try to convert this curve into an Ellipse using a custom tolerance.
 
TryGetEllipse(Plane, Ellipse) 
Try to convert this curve into an Ellipse within RhinoMath.ZeroTolerance.
 
TryGetEllipse(Plane, Ellipse, Double) 
Try to convert this curve into an Ellipse using a custom tolerance.
 
TryGetPlane(Plane)  Test a curve for planarity and return the plane.  
TryGetPlane(Plane, Double)  Test a curve for planarity and return the plane.  
TryGetPolyline(Polyline) 
Several types of Curve can have the form of a polyline
including a degree 1 NurbsCurve, a PolylineCurve,
and a PolyCurve all of whose segments are some form of
polyline. IsPolyline tests a curve to see if it can be
represented as a polyline.
 
TryGetPolyline(Polyline, Double) 
Several types of Curve can have the form of a polyline
including a degree 1 NurbsCurve, a PolylineCurve,
and a PolyCurve all of whose segments are some form of
polyline. IsPolyline tests a curve to see if it can be
represented as a polyline.
