pymel.core.nodetypes.NurbsCurve

class NurbsCurve(*args, **kwargs)

class counterpart of mel function curve

The curve command creates a new curve from a list of control vertices (CVs). A string is returned containing the pathname to the newly created curve. You can create a curve from points either in world space or object (local) space, either with weights or without. You can replace an existing curve by using the “-r/replace” flag. You can append a point to an existing curve by using the “-a/append” flag. To create a curve-on-surface, use the curveOnSurface command. To change the degree of a curve, use the rebuildCurve command. To change the of parameter range curve, use the rebuildCurve command.

Form = Enum( EnumValue('Form', 0, 'invalid'), EnumValue('Form', 1, 'open'), EnumValue('Form', 2, 'closed'), EnumValue('Form', 3, 'periodic'), EnumValue('Form', 4, 'last'))

area(tolerance=0.001)

This method returns the area bounded by this curve. The curve must be closed and planar.

Parameters :

tolerance : float

The amount of error (epsilon value) in the calculation

Return type:

float

Derived from api method maya.OpenMaya.MFnNurbsCurve.area

closestPoint(toThisPoint, param=None, tolerance=0.001, space='preTransform')

This method determines the closest point on the curve to the given point.

Parameters :

toThisPoint : Point

The point to test

param : float

pointer to a double. If non-null, on successful returns this will contain the parameter value of the returned point.

tolerance : float

The amount of error (epsilon value) in the calculation

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Point

Derived from api method maya.OpenMaya.MSpace.closestPoint

copy(source, parentOrOwner='MObject::kNullObj')

This method creates a copy of a nurbs curve.

Parameters :

source : PyNode

the curve to be copied

parentOrOwner : PyNode

the DAG parent or kNurbsCurveData the new curve will belong to

Return type:

PyNode

Derived from api method maya.OpenMaya.MFnNurbsCurve.copy

createWithEditPoints(editPoints, degree, form, create2D, createRational, uniformParam, parentOrOwner='MObject::kNullObj')

This method creates a nurbs curve from the given edit points and sets this function set to operate on the new curve.

Parameters :

editPoints : Point list

an array of edit points

degree : int

the degree to create the curve with

form : BezierCurve.Form

either kOpen, kClosed, kPeriodic

values: ‘open’, ‘closed’, ‘periodic’

create2D : bool

indictates whether to create 2D or 3D curve

createRational : bool

true means curve being created will be rational

uniformParam : bool

true means curve being created will have uniform parameterization, false means chord length

parentOrOwner : PyNode

the DAG parent or kNurbsCurveData the new curve will belong to

Return type:

PyNode

Derived from api method maya.OpenMaya.MFnNurbsCurve.createWithEditPoints

cvs(startIndex, endIndex)

This method is used to directly access a contiguous group of CVs. The returned group can be accessed via the MItCurveCV class. Any modifications to these CVs will affect this curve. updateCurve should be called to cause the curve to redraw itself.

Parameters :

startIndex : int

the start index for the CVs to return

endIndex : int

the end index for the CVs to return

Return type:

PyNode

Derived from api method maya.OpenMaya.MFnNurbsCurve.cvs

degree()

Return the degree of this curve. If the degree cannot be determined then 0 is returned.

Return type:int

Derived from api method maya.OpenMaya.MFnNurbsCurve.degree

distanceToPoint(pt, space='preTransform')

This method determines the distance from the given point to closest point on the curve.

Parameters :

pt : Point

The point to calculate the distance to

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

float

Derived from api method maya.OpenMaya.MSpace.distanceToPoint

findParamFromLength(partLength)

Given the length along the curve, find the parameter value that corresponds to it. If the parameter value cannot be found for the given length then ReturnStatus is set to kInvalidParameter and the parameter for the end point of the curve is returned.

Parameters :

partLength : float

Length along the curve to find parameter value at

Return type:

float

Derived from api method maya.OpenMaya.MFnNurbsCurve.findParamFromLength

form()

This method returns the form of the curve. The curve can be open, closed, or periodic.

Return type:BezierCurve.Form

Derived from api method maya.OpenMaya.MFnNurbsCurve.form

getCV(index, space='preTransform')

Get the CV at the given index.

Parameters :

index : int

The index of the CV that will be retrieved

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Point

Derived from api method maya.OpenMaya.MSpace.getCV

getCVs(space='preTransform')

Get the positions of the CVs of this curve. The returned group can be accessed via the MPointArray class. Any modifications to these CVs will not affect this curve. setCVs should be called to modify the original curve. updateCurve should be called to cause the curve to redraw itself.

Parameters :

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Point list

Derived from api method maya.OpenMaya.MSpace.getCVs

getDerivativesAtParm(param, space)

Evaluate the surface at the given parameter returning the position, first derivative and optionally the seecond derivative. Derivatives are not normalized.

Parameters :

param : float

U parameter value to evaluate

space : Space.Space

Coordinate space for the returned vectors

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

(Point, Vector, Vector)

Derived from api method maya.OpenMaya.MSpace.getDerivativesAtParm

getKnot(index)

Get the parameter value of the specified knot for this curve. Knot indices range from 0 to numKnots() - 1

Parameters :

index : int

The knot index

Return type:

float

Derived from api method maya.OpenMaya.MFnNurbsCurve.knot

getKnotDomain()

Return the range corresponding to the maximum and minimum parameter values for this curve.

Return type:(float, float)

Derived from api method maya.OpenMaya.MFnNurbsCurve.getKnotDomain

getKnots()

This method retrieves a copy of the knot array for this curve.

Return type:float list

Derived from api method maya.OpenMaya.MFnNurbsCurve.getKnots

getParamAtPoint(atThisPoint, space='preTransform')

This method retrieves the parameter value corresponding to the given point on the curve.

Parameters :

atThisPoint : Point

Point to check

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

float

Derived from api method maya.OpenMaya.MSpace.getParamAtPoint

getPointAtParam(param, space='preTransform')

Returns the point in space that is at the given parameter value of the curve. If the parameter value does not give a valid point on the curve, then MS::kInvalidParameter is returned.

Parameters :

param : float

The parameter value that we are examining

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Point

Derived from api method maya.OpenMaya.MSpace.getPointAtParam

hasHistoryOnCreate()

This method determines if the shape was created with history.

Return type:bool

Derived from api method maya.OpenMaya.MFnNurbsCurve.hasHistoryOnCreate

isParamOnCurve(param)

Determines whether the specified parameter value is within the bounds of the knot vector of this curve

Parameters :

param : float

The parameter value to check

Return type:

bool

Derived from api method maya.OpenMaya.MFnNurbsCurve.isParamOnCurve

isPlanar(planeNormal=None)

This method determines if this curve is a planar curve. If planeNormal is non-NULL then the normal to the plane containing this curve is returned in this location.

Parameters :

planeNormal : Vector

Normal to the plane containing this curve

Return type:

bool

Derived from api method maya.OpenMaya.MFnNurbsCurve.isPlanar

isPointOnCurve(point, tolerance=0.001, space='preTransform')

Determines whether the given point is on this curve.

Parameters :

point : Point

The point to test

tolerance : float

The amount of error (epsilon value) in the calculation

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

bool

Derived from api method maya.OpenMaya.MSpace.isPointOnCurve

length(tolerance=0.001)

Return the arc length of this curve or 0.0 if it cannot be computed.

Parameters :

tolerance : float

The amount of error (epsilon value) in the calculation

Return type:

float

Derived from api method maya.OpenMaya.MFnNurbsCurve.length

makeMultipleEndKnots()

This method gives end knots full multiplicity. This ensures the end points of the curve interpolate the first and last CVs. It can also be used to convert a periodic curve to a closed curve. Derived from api method maya.OpenMaya.MFnNurbsCurve.makeMultipleEndKnots

Undo is not currently supported for this method

normal(param, space='preTransform')

This method returns the normal at the given parameter value on the curve. For degree 1 curves the normal is the vector at right angles to the curve that lies in the average plane of the curve. For higher degrees the normal is defined by the local curvature at param.

Parameters :

param : float

The parameter of the point on the curve from which to get the normal

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Vector

Derived from api method maya.OpenMaya.MSpace.normal

numCVs(editableOnly=True)

Returns the number of CVs.

Parameters :

editableOnly : bool

If editableOnly evaluates to True (default), then this will return the number of cvs that can be actually edited (and also the highest index that may be used for cv’s - ie, if

myCurve.numCVs(editableOnly=True) == 4

then allowable cv indices go from

myCurve.cv[0] to mySurf.cv[3]

If editablyOnly is False, then this will return the underlying number of cvs used to define the mathematical curve - degree + numSpans.

These will only differ if the form is ‘periodic’, in which case the editable number will be numSpans (as the last ‘degree’ cv’s are ‘locked’ to be the same as the first ‘degree’ cvs). In all other cases, the number of cvs will be degree + numSpans.

Examples :

>>> from pymel.core import *
>>> # a periodic curve
>>> myCurve = curve(name='periodicCurve1', d=3, periodic=True, k=(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), pw=[(4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1), (0, 5.5, 0, 1), (-4, 4, 0, 1), (-5.5, 0, 0, 1), (-4, -4, 0, 1), (0, -5.5, 0, 1), (4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1)] )
>>> myCurve.cv
NurbsCurveCV(u'periodicCurveShape1.cv[0:7]')
>>> myCurve.numCVs()
8
>>> myCurve.numCVs(editableOnly=False)
11
>>>
>>> # an open curve
>>> myCurve = curve(name='openCurve1', d=3, periodic=False, k=(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), pw=[(4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1), (0, 5.5, 0, 1), (-4, 4, 0, 1), (-5.5, 0, 0, 1), (-4, -4, 0, 1), (0, -5.5, 0, 1), (4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1)] )
>>> myCurve.cv
NurbsCurveCV(u'openCurveShape1.cv[0:10]')
>>> myCurve.numCVs()
11
>>> myCurve.numCVs(editableOnly=False)
11

Return type:

int

numEPs(editableOnly=True)

Returns the number of EPs.

Examples :

>>> from pymel.core import *
>>> # a periodic curve
>>> myCurve = curve(name='periodicCurve2', d=3, periodic=True, k=(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), pw=[(4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1), (0, 5.5, 0, 1), (-4, 4, 0, 1), (-5.5, 0, 0, 1), (-4, -4, 0, 1), (0, -5.5, 0, 1), (4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1)] )
>>> myCurve.ep
NurbsCurveEP(u'periodicCurveShape2.ep[0:7]')
>>> myCurve.numEPs()
8
>>>
>>> # an open curve
>>> myCurve = curve(name='openCurve2', d=3, periodic=False, k=(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), pw=[(4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1), (0, 5.5, 0, 1), (-4, 4, 0, 1), (-5.5, 0, 0, 1), (-4, -4, 0, 1), (0, -5.5, 0, 1), (4, -4, 0, 1), (5.5, 0, 0, 1), (4, 4, 0, 1)] )
>>> myCurve.ep
NurbsCurveEP(u'openCurveShape2.ep[0:8]')
>>> myCurve.numEPs()
9

Return type:

int

numKnots()

Return the number of knots for this curve. If the number of knots cannot be determined then 0 is returned.

Return type:int

Derived from api method maya.OpenMaya.MFnNurbsCurve.numKnots

numSpans()

Return the number of spans for this curve. If the number of spans cannot be determined then 0 is returned.

Return type:int

Derived from api method maya.OpenMaya.MFnNurbsCurve.numSpans

removeKnot(atThisParam, removeAll=False)

Remove knot(s) from this curve. If removeAll is true then all of the knots except for the knot at the given parameter value will be removed. If removeAll is false then only the knot at the given parameter value will be removed.

Parameters :

atThisParam : float

Status code

removeAll : bool

Determines whether we remove all knots, or all but one

Derived from api method maya.OpenMaya.MFnNurbsCurve.removeKnot

Undo is not currently supported for this method

reverse(constructionHistory=False)

This method reverse the curve direction.

Parameters :

constructionHistory : bool

This parameter has no effect. Regardless of how it is set, if the function set was initialized with the DAG path of a curve node which already has history, then the reverse operation will be added into that history, otherwise the reverse operation will be applied directly to the curve’s data and no history will be left behind.

Derived from api method maya.OpenMaya.MFnNurbsCurve.reverse

Undo is not currently supported for this method

setCV(index, pt, space='preTransform')

Set the CV at the given index to the given point. The method updateCurve should be called to trigger changes in the curve.

Parameters :

index : int

The index of the CV that will be changed

pt : Point

The new value that the CV will take

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Derived from api method maya.OpenMaya.MSpace.setCV

setCVs(array, space='preTransform')

Set the CVs for this curve to the given points.

Parameters :

array : Point list

The array of point values for the CVs

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Derived from api method maya.OpenMaya.MSpace.setCVs

setKnot(index, param)

Set the given knot’s parameter value. Knot indices range from 0 to numKnots() - 1 .

Parameters :

index : int

Index of the knot to be set

param : float

The parameter value that the knot will take

Derived from api method maya.OpenMaya.MFnNurbsCurve.setKnot

setKnots(array, startIndex, endIndex)

This method is used to set the values of a contiguous group of knots of the curve. The range of knots to set is specified using the start and end index. The knots of index startIndex to endIndex inclusive will be set using the value in the double array.

Parameters :

array : float list

a double array of knot points

startIndex : int

the starting index of the knots to be altered.

endIndex : int

the ending index of the knots to be altered.

Derived from api method maya.OpenMaya.MFnNurbsCurve.setKnots

tangent(param, space='preTransform')

This method returns the tangent at the given parameter value on the curve. The resulting tangent vector is normalized.

Parameters :

param : float

The parameter of the point on the curve from which to get the tangent

space : Space.Space

Specifies the coordinate system for this operation

values: ‘transform’, ‘preTransform’, ‘object’, ‘world’

Return type:

Vector

Derived from api method maya.OpenMaya.MSpace.tangent

updateCurve()

This method signals that this curve has changed and needs to be recalculated. Derived from api method maya.OpenMaya.MFnNurbsCurve.updateCurve

Undo is not currently supported for this method