MFnNurbsCurve Class Reference

#include <MFnNurbsCurve.h>

Class Description

NURBS curve function set.

This is the function set for NURBS (Non-Uniform Rational B-Spline) curves.

The shape of a NURBS curve is defined by an array of CVs (control vertices), an array of knot values, a degree, and a form. There are 3 possible "forms" for the curve: open, closed and periodic.

The open and closed forms are quite similar, and in fact a closed curve will become an open curve if either the first or last CV is moved so that they are no longer coincident. To create an open or closed curve of degree N with M spans, you must provide M+N CVs. This implies that for a degree N curve, you must specify at least N+1 CVs to get a curve with a single span.

The number of knots required for a curve is M + 2N - 1. If you want the curve to start exactly at the first CV and end exactly at the last CV, then the knot vector must be structured to have degree N "multiplicity" at the beginning and end. This means that the first N knots must be identical, and the last N knots must be identical.

A periodic curve is a special case of a closed curve. Instead of having just the first and last CVs coincident, the last N CVs in the curve must overlap the first N CVs. This results in a curve with no tangent break at the seam where the ends meet. The last N CVs in a periodic curve are permanently bound to the first N CVs, and Maya will not allow those last N CVs to be repositioned. If one or more of the first N CVs of the curve are repositioned, the overlapping CV's will remain bound, and will also be moved.

In order to create a periodic curve, you must specify at least 2N+1 CVs, so that that last N can overlap the first N and you still have 1 non-overlapping CV left. The number of CVs required to create a periodic curve is still N+M (with a lower limit of 2N+1), but you must ensure that the positions of the last N CVs are identical to the positions of the first N.

You still need M + 2N - 1 knots for a periodic curve, but the knot values required are more restrictive than for open or closed curves because of the overlap at the ends, The difference between the first N pairs of knots values should be equal to the difference between the last N pairs. Additionally there can be no knot multiplicity at the ends of the curve, because that would compromise the tangent continuity property. So an example knot sequence could begin with knots at { -(N-2), -(N-1), ... , 0}.

Managing different knot representations in external applications

Note that some third party applications use a different format for knots, where the number of knots required for a curve is M+2N+1 rather than M+2N-1 as used in Maya. Both knot representations are equivalent mathematically. To convert from one of these external representations into the Maya representation, simply omit the first and last knots from the external representation when creating the Maya representation. To convert from the Maya representation into the external representation, add two new knots at the beginning and end of the Maya knot sequence. The value of these new knots depends on the existing knot sequence. For a knot sequence with multiple end knots, simply duplicate the existing first and last knots once more, for example:

Maya representation: {0,0,0,...,N,N,N}
External representation: {0,0,0,0,...,N,N,N,N}

For a knot sequence with uniform end knots, create the new knots offset at an interval equal to the existing first and last knot intervals, for example:

Maya representation: {0,1,2,...,N,N+1,N+2}
External representation: {-1,0,1,2,...,N,N+1,N+2,N+3}

Examples:

Inheritance diagram for MFnNurbsCurve:

Public Types
enum	Form {   kInvalid =0, kOpen, kClosed, kPeriodic,   kLast }
	Forms that a curve may take. More...
Public Types inherited from MFnDagNode
enum	{ kNextPos = 0xff }
	Anonymous enum to store constant values. More...
enum	MObjectColorType { kUseDefaultColor = 0, kUseIndexColor, kUseRGBColor }
	Enum to set how an object is colored. More...
Public Types inherited from MFnDependencyNode
enum	MAttrClass { kLocalDynamicAttr = 1, kNormalAttr, kExtensionAttr, kInvalidAttr }
	Specifies the scope of the attribute. More...
enum	MdgTimerState { kTimerOff, kTimerOn, kTimerUninitialized, kTimerInvalidState }
	Possible states for the node's timer. More...
enum	MdgTimerMetric {   kTimerMetric_callback, kTimerMetric_compute, kTimerMetric_dirty, kTimerMetric_draw,   kTimerMetric_fetch, kTimerMetric_callbackViaAPI, kTimerMetric_callbackNotViaAPI, kTimerMetric_computeDuringCallback,   kTimerMetric_computeNotDuringCallback, kTimerMetrics }
	The different timer metrics which can be queried. More...
enum	MdgTimerType { kTimerType_self, kTimerType_inclusive, kTimerType_count, kTimerTypes }
	The types of timers which can be queried. More...

Public Member Functions
virtual MFn::Type	type () const
	Function set type. More...
virtual	~MFnNurbsCurve ()
	Destructor. More...
	MFnNurbsCurve ()
	Default constructor.
	MFnNurbsCurve (MObject &object, MStatus *ReturnStatus=NULL)
	Constructor. More...
	MFnNurbsCurve (const MDagPath &object, MStatus *ret=NULL)
	Constructor. More...
MObject	create (const MPointArray &controlVertices, const MDoubleArray &knotSequences, unsigned int degree, Form agForm, bool create2D, bool createRational, MObject &parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	This method creates a nurbs curve from the given control vertices and knot vector and sets this function set to operate on the new curve. More...
MObject	createWithEditPoints (const MPointArray &editPoints, unsigned int degree, Form agForm, bool create2D, bool createRational, bool uniformParam, MObject &parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	This method creates a nurbs curve from the given edit points and sets this function set to operate on the new curve. More...
MObject	create (const MObjectArray &sources, MObject &parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	This method creates a single curve that combines all the curves in the MObjectArray. More...
MObject	copy (const MObject &source, MObject &parentOrOwner=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	This method creates a copy of a nurbs curve. More...
MStatus	reverse (bool constructionHistory=false)
	This method reverse the curve direction. More...
MStatus	makeMultipleEndKnots ()
	This method gives end knots full multiplicity. More...
MObject	cv (unsigned int index, MStatus *ReturnStatus=NULL) const
	Returns a CV as a component. More...
MStatus	getCV (unsigned int index, MPoint &pt, MSpace::Space space=MSpace::kObject) const
	Get the CV at the given index. More...
MStatus	setCV (unsigned int index, const MPoint &pt, MSpace::Space space=MSpace::kObject)
	Set the CV at the given index to the given point. More...
Form	form (MStatus *ReturnStatus=NULL) const
	This method returns the form of the curve. More...
int	degree (MStatus *ReturnStatus=NULL) const
	Return the degree of this curve. More...
int	numCVs (MStatus *ReturnStatus=NULL) const
	Return the number of CVs for this curve. More...
int	numSpans (MStatus *ReturnStatus=NULL) const
	Return the number of spans for this curve. More...
int	numKnots (MStatus *ReturnStatus=NULL) const
	Return the number of knots for this curve. More...
MStatus	getKnotDomain (double &start, double &end) const
	Return the range corresponding to the maximum and minimum parameter values for this curve. More...
MStatus	getKnots (MDoubleArray &array) const
	This method retrieves a copy of the knot array for this curve. More...
MStatus	setKnots (const MDoubleArray &array, unsigned int startIndex, unsigned int endIndex)
	This method is used to set the values of a contiguous group of knots of the curve. More...
MStatus	setKnot (unsigned int index, double param)
	Set the given knot's parameter value. More...
MObject	cvs (unsigned int startIndex, unsigned int endIndex, MStatus *ReturnStatus=NULL) const
	Returns a contiguous group of CVs as a component. More...
MStatus	getCVs (MPointArray &array, MSpace::Space space=MSpace::kObject) const
	Get the positions of the CVs of this curve. More...
MStatus	setCVs (const MPointArray &array, MSpace::Space space=MSpace::kObject)
	Set the CVs for this curve to the given points. More...
double	knot (unsigned int index, MStatus *ReturnStatus=NULL) const
	Get the parameter value of the specified knot for this curve. More...
MStatus	removeKnot (double atThisParam, bool removeAll=false)
	Remove one or more knots at the given parameter. More...
bool	isPointOnCurve (const MPoint &point, double tolerance=kMFnNurbsEpsilon, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	Determines whether the given point is on this curve. More...
MStatus	getPointAtParam (double param, MPoint &point, MSpace::Space space=MSpace::kObject) const
	Returns the point in space that is at the given parameter value of the curve. More...
MStatus	getParamAtPoint (const MPoint &atThisPoint, double &param, MSpace::Space space=MSpace::kObject) const
	This method retrieves the parameter value corresponding to the given point on the curve. More...
MStatus	getParamAtPoint (const MPoint &atThisPoint, double &param, double tolerance, MSpace::Space space=MSpace::kObject) const
	This method retrieves the parameter value corresponding to the given point on the curve. More...
bool	isParamOnCurve (double param, MStatus *ReturnStatus=NULL) const
	Determines whether the specified parameter value is within the bounds of the knot vector of this curve. More...
MVector	normal (double param, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	This method returns the normal at the given parameter value on the curve. More...
MVector	tangent (double param, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	This method returns the tangent at the given parameter value on the curve. More...
MStatus	getDerivativesAtParm (double param, MPoint &pos, MVector &dU, MSpace::Space space, MVector *dUU=NULL) const
	Evaluate the curve at the given parameter returning the position, first derivative and optionally the second derivative. More...
bool	isPlanar (MVector *planeNormal=NULL, MStatus *ReturnStatus=NULL) const
	This method determines if this curve is a planar curve. More...
MPoint	closestPoint (const MPoint &toThisPoint, double *param=NULL, double tolerance=kMFnNurbsEpsilon, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	This method determines the closest point on the curve to the given point. More...
MPoint	closestPoint (const MPoint &toThisPoint, bool paramAsGuess, double *param=NULL, double tolerance=kMFnNurbsEpsilon, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	This method determines the closest point on the curve to the given point. More...
double	distanceToPoint (const MPoint &pt, MSpace::Space space=MSpace::kObject, MStatus *ReturnStatus=NULL) const
	Returns the distance from the given point to the point on the curve which is closest to it. More...
double	area (double tolerance=kMFnNurbsEpsilon, MStatus *ReturnStatus=NULL) const
	This method returns the area bounded by this curve. More...
double	length (double tolerance=kMFnNurbsEpsilon, MStatus *ReturnStatus=NULL) const
	Return the arc length of this curve or 0.0 if it cannot be computed. More...
double	findParamFromLength (double partLength, MStatus *ReturnStatus=NULL) const
	Returns the parameter value corresponding to a given length along the curve. More...
double	findLengthFromParam (double param, MStatus *ReturnStatus=NULL) const
	Returns the length along the curve corresponding to a given parameter value on the curve. More...
bool	hasHistoryOnCreate (MStatus *ReturnStatus=NULL) const
	This method determines if the shape was created with history. More...
MStatus	updateCurve ()
	This method signals that this curve has changed and needs to be recalculated. More...
MObject	rebuild (unsigned int spans, unsigned int degree=3, unsigned int keepRange=1, unsigned int endKnots=0, bool keepEndPoints=true, bool keepTangents=true, bool keepControlPoints=false, float tolerance=0.01f, MStatus *ReturnStatus=NULL) const
	This method rebuilds a new curve based on the current curve and parameters. More...
	MFnNurbsCurve (const MObject &object, MStatus *ret=NULL)
	Constructor. More...
Public Member Functions inherited from MFnDagNode
virtual	~MFnDagNode ()
	Destructor. More...
	MFnDagNode ()
	Class Constructor. More...
	MFnDagNode (MObject &object, MStatus *ret=NULL)
	This method is not available in Python. More...
	MFnDagNode (const MDagPath &object, MStatus *ret=NULL)
	Class Constructor. More...
MObject	create (const MTypeId &typeId, MObject &parent=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	Creates a new DAG node with the given type tag. More...
MObject	create (const MTypeId &typeId, const MString &name, MObject &parent=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	Creates a new DAG node with the given type tag. More...
MObject	create (const MString &type, MObject &parent=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	Creates a new DAG node with the given type tag. More...
MObject	create (const MString &type, const MString &name, MObject &parent=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	Creates a new DAG node with the given type tag. More...
unsigned int	parentCount (MStatus *ReturnStatus=NULL) const
	Determines the number of parent Nodes of the Node. More...
MObject	parent (unsigned int i, MStatus *ReturnStatus=NULL) const
	Queries the DAG Node attached to the Function Set for the parent Node corresponding to the given index. More...
MStatus	addChild (MObject &child, unsigned int index=kNextPos, bool keepExistingParents=false)
	Makes the given DAG Node a child of the DAG Node to which this instance of the Function Set is attached. More...
MStatus	removeChild (MObject &child)
	Removes the given DAG Node from the parent. More...
MStatus	removeChildAt (unsigned int index)
	Removes the child at the given index from the parent. More...
unsigned int	childCount (MStatus *ReturnStatus=NULL) const
	Determines the number of child Nodes of the Node. More...
MObject	child (unsigned int i, MStatus *ReturnStatus=NULL) const
	Queries the DAG Node attached to the Function Set for the child Node corresponding to the given index. More...
MObject	dagRoot (MStatus *ReturnStatus=NULL)
	Determines the root of the first DAG Path to the DAG Node attached to the Function Set. More...
bool	hasParent (const MObject &node, MStatus *ReturnStatus=NULL) const
	Determines whether or not the given Node is a parent of the DAG Node attached to the Function Set. More...
bool	hasChild (const MObject &node, MStatus *ReturnStatus=NULL) const
	Determines whether or not the given Node is a child of the DAG Node attached to the Function Set. More...
bool	isChildOf (const MObject &node, MStatus *ReturnStatus=NULL) const
	Determines whether or not the DAG Node attached to the Function Set is a child of the given node. More...
bool	isParentOf (const MObject &node, MStatus *ReturnStatus=NULL) const
	Determines whether or not the DAG Node attached to the Function Set is a parent of the given node. More...
bool	inUnderWorld (MStatus *ReturnStatus=NULL) const
	Determines whether or not the DAG Node is an underworld node. More...
bool	inModel (MStatus *ReturnStatus=NULL) const
	Determines whether or not the DAG Node is in the model. More...
bool	isInstanceable (MStatus *ReturnStatus=NULL) const
	Returns true if the DAG node can be instanced, and false otherwise. More...
MStatus	setInstanceable (const bool how)
	Sets whether or not the DAG node is instanceable. More...
bool	isInstanced (bool indirect=true, MStatus *ReturnStatus=NULL) const
	Determines whether the DAG Node attached to the Function Set is directly or indirectly instanced. More...
bool	isInstancedAttribute (const MObject &attr, MStatus *ReturnStatus=NULL) const
	Returns true if the specified attribute is instanced. More...
unsigned int	instanceCount (bool total, MStatus *ReturnStatus=NULL) const
	Determines the number of times the Node attached to the Function Set is instanced. More...
MObject	duplicate (bool instance=false, bool instanceLeaf=false, MStatus *ReturnStatus=NULL) const
	This method duplicates the DAG hierarchy rooted at the current node. More...
MStatus	getPath (MDagPath &path) const
	Returns a DAG Path to the DAG Node attached to the Function Set. More...
MStatus	getAllPaths (MDagPathArray &paths) const
	Determines all DAG Paths to the DAG Node attached to the Function Set. More...
MString	fullPathName (MStatus *ReturnStatus=NULL) const
	Return a string representing the full path from the root of the dag to this object. More...
MString	partialPathName (MStatus *ReturnStatus=NULL) const
	Return a string representing the partial path from the root of the dag to this object. More...
MMatrix	transformationMatrix (MStatus *ReturnStatus=NULL) const
	Returns the object space transformation matrix for this DAG node. More...
bool	isIntermediateObject (MStatus *ReturnStatus=NULL) const
	Returns true if this object is an intermediate in a geometry calculation. More...
MStatus	setIntermediateObject (bool isIntermediate)
	Sets whether this object is an intermediate in a geometry calculation. More...
int	objectColor (MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...
MStatus	setObjectColor (int color)
	Sets the index for the current user defined inactive color used by the node. More...
bool	usingObjectColor (MStatus *ReturnStatus=NULL) const
MStatus	setUseObjectColor (bool useObjectColor)
MObjectColorType	objectColorType (MStatus *ReturnStatus=NULL) const
	Determines whether or not the user defined inactive color will be used for the node, or whether the default inactive color will be used. More...
MStatus	setObjectColorType (MObjectColorType type)
	Sets whether or not the user defined inactive object color will be used. More...
MStatus	setObjectColor (const MColor &color)
	Sets the color value for the current user defined inactive color used by the node. More...
MColor	objectColorRGB (MStatus *ReturnStatus=NULL) const
	Determines the RGB color for the current user defined inactive color used by the node. More...
int	objectColorIndex (MStatus *ReturnStatus=NULL) const
	Determines the index for the current user defined inactive color used by the node. More...
MColor	hiliteColor (MStatus *ReturnStatus=NULL) const
	Determines the current hilite color used by the node. More...
bool	usingHiliteColor (MStatus *ReturnStatus=NULL) const
	Determines whether or not the hilite color will be used for the node. More...
MColor	dormantColor (MStatus *ReturnStatus=NULL) const
	Determines the dormant color used by this node. More...
MColor	activeColor (MStatus *ReturnStatus=NULL) const
	Determines the active color used by this node. More...
bool	drawOverrideEnabled (MStatus *ReturnStatus=NULL) const
	Determines whether or not draw override is turned on for this node. More...
bool	drawOverrideIsReference (MStatus *ReturnStatus=NULL) const
	Determines whether or not Display Type of the draw override is Reference for this node. More...
bool	drawOverrideIsTemplate (MStatus *ReturnStatus=NULL) const
	Determines whether or not Display Type of the draw override is Template for this node. More...
bool	drawOverrideColor (MColor &color, MStatus *ReturnStatus=NULL) const
	Determines the draw override color used by this node. More...
MStatus	getConnectedSetsAndMembers (unsigned int instanceNumber, MObjectArray &sets, MObjectArray &comps, bool renderableSetsOnly) const
	Returns all the sets connected to the specified instance of this DAG object. More...
MBoundingBox	boundingBox (MStatus *ReturnStatus=NULL) const
	Returns the bounding box for the dag node in object space. More...
MDagPath	dagPath (MStatus *ReturnStatus=NULL) const
	Returns the DagPath to which the Function Set is attached. More...
virtual MStatus	setObject (const MDagPath &path)
	Attaches Function Set to the DAG Node that has the given DAG Path. More...
virtual MStatus	setObject (MObject &object)
	Attaches Function Set to given DAG Node. More...
MObject	model (MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...
	MFnDagNode (const MObject &object, MStatus *ret=NULL)
	No script support. More...
virtual MStatus	setObject (const MObject &object)
	No script support. More...
Public Member Functions inherited from MFnDependencyNode
virtual	~MFnDependencyNode ()
	Destructor.
	MFnDependencyNode ()
	Default constructor.
	MFnDependencyNode (MObject &object, MStatus *ReturnStatus=NULL)
	Constructor. More...
MObject	create (const MTypeId &typeId, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type tag. More...
MObject	create (const MTypeId &typeId, const MString &name, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type tag. More...
MObject	create (const MString &type, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type. More...
MObject	create (const MString &type, const MString &name, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type. More...
MTypeId	typeId (MStatus *ReturnStatus=NULL) const
	Returns the type id of this node. More...
MString	typeName (MStatus *ReturnStatus=NULL) const
	Returns the type name of this node. More...
MString	name (MStatus *ReturnStatus=NULL) const
	Returns the name of this node. More...
MString	absoluteName (MStatus *ReturnStatus=NULL) const
	Returns the absolute name of this node. More...
MString	pluginName (MStatus *ReturnStatus=NULL) const
	Returns the name of the plug-in this MFnDependendencyNode was defined in. More...
MString	setName (const MString &name, bool createNamespace=false, MStatus *ReturnStatus=NULL)
	Sets the name of this node. More...
MUuid	uuid (MStatus *ReturnStatus=NULL) const
	Returns the node's UUID. More...
void	setUuid (const MUuid &uuid, MStatus *ReturnStatus=NULL)
	Sets the node's UUID. More...
MStatus	getConnections (MPlugArray &array) const
	Get all of the current connections to this node as an array of plugs. More...
unsigned int	attributeCount (MStatus *ReturnStatus=NULL) const
	Returns the number of attributes that this node has. More...
MObject	attribute (unsigned int index, MStatus *ReturnStatus=NULL) const
	Finds the attribute of this node at the given index. More...
MObject	reorderedAttribute (unsigned int index, MStatus *ReturnStatus=NULL) const
	Some nodes, such as the various animCurve nodes, require that their attributes be set in a specific order for proper operation. More...
MObject	attribute (const MString &attrName, MStatus *ReturnStatus=NULL) const
	Finds the attribute of this node that has the given name. More...
MAttrClass	attributeClass (const MObject &attr, MStatus *ReturnStatus=NULL) const
	Returns the class (normal, dynamic, extension) of the specified attribute. More...
MStatus	getAffectedAttributes (const MObject &attr, MObjectArray &affectedAttributes) const
	Returns an array of attributes that are affected by the attribute passed in. More...
MStatus	getAffectedByAttributes (const MObject &attr, MObjectArray &affectedByAttributes) const
	Returns an array of attributes that affect the attribute passed in, attr. More...
MPlug	findPlug (const MObject &attr, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
	Attempt to find a plug for the given attribute. More...
MPlug	findPlug (const MString &attrName, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
	Attempt to find a plug for the given attribute. More...
MPlug	findPlug (const MObject &attr, MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...
MPlug	findPlug (const MString &attrName, MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...
MStatus	addAttribute (const MObject &attr)
	Add a new dynamic attibute to this node. More...
MStatus	removeAttribute (const MObject &attr)
	Remove a dynamic attribute from a node. More...
MPxNode *	userNode (MStatus *ReturnStatus=NULL) const
	If the function set's node is a plug-in node, then this method will extract the MPxNode pointer from it. More...
bool	isFromReferencedFile (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node came from a referenced file. More...
bool	isShared (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node is shared. More...
bool	isTrackingEdits (MStatus *ReturnStatus=NULL) const
	Returns whether or not edits on the given node are being tracked by the generalized edit system. More...
bool	hasUniqueName (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node's name is unique within the scene. More...
MString	parentNamespace (MStatus *ReturnStatus=NULL) const
	Returns the name of the namespace in which this node resides. More...
bool	isLocked (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node is locked. More...
MStatus	setLocked (bool locked)
	Locks or unlocks this node. More...
bool	isNewAttribute (const MObject &attr, MStatus *ReturnStatus=NULL) const
	Indicates whether or not the specified attribute was added to this node within the current scene. More...
MStatus	setFlag (unsigned int flag, bool state)
	Sets the state of the specified flag for the node. More...
bool	isFlagSet (unsigned int flag, MStatus *ReturnStatus=NULL) const
	Retrieves the current state of the specified flag for a node. More...
bool	isDefaultNode (MStatus *ReturnStatus=NULL) const
	Returns true if the node is a default node. More...
MStatus	setDoNotWrite (bool flag)
	Use this method to mark the "do not write" state of this node. More...
bool	canBeWritten (MStatus *ReturnStatus=NULL) const
	Returns the do not write state of the node. More...
bool	hasAttribute (const MString &name, MStatus *ReturnStatus=NULL) const
	Returns true if the node already has an attribute with the given name. More...
MObject	getAliasAttr (bool force, MStatus *ReturnStatus=NULL)
	Returns the node's alias attribute, which is a special attribute used to store information about the node's attribute aliases. More...
bool	setAlias (const MString &alias, const MString &name, const MPlug &plug, bool add=true, MStatus *ReturnStatus=NULL)
	Sets or removes an alias (i.e. More...
bool	findAlias (const MString &alias, MObject &attrObj, MStatus *ReturnStatus=NULL) const
	Retrieves the attribute with the given alias. More...
bool	getAliasList (MStringArray &strArray, MStatus *ReturnStatus=NULL)
	Returns a list of all attribute aliases for this node. More...
MString	plugsAlias (const MPlug &plug, MStatus *ReturnStatus=NULL)
	Returns the alias for the plug's attribute or the empty string if that attribute has no alias. More...
MStatus	setIcon (const MString &filename)
	Associates a custom icon with the node for display in the Maya UI. More...
MString	icon (MStatus *ReturnStatus=NULL) const
	Returns the custom icon filename associated with the node. More...
MStatus	getExternalContent (MExternalContentInfoTable &table) const
	Returns the external content (files) that this node depends on. More...
MStatus	addExternalContentForFileAttr (MExternalContentInfoTable &table, const MObject &attr) const
	Adds content info to the specified table from a file path attribute. More...
MStatus	setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &table)
	Sets content info in the specified attribute from the table. More...
MStatus	setExternalContent (const MExternalContentLocationTable &table)
	Changes the location of external content. More...
MString	setName (const MString &name, MStatus *ReturnStatus)
	OBSOLETE FUNCTION, NO SCRIPT SUPPORT. More...
	MFnDependencyNode (const MObject &object, MStatus *ReturnStatus=NULL)
	NO SCRIPT SUPPORT. More...
bool	getPlugsAlias (const MPlug &plug, MString &aliasName, MStatus *ReturnStatus=NULL)
	NO SCRIPT SUPPORT. More...
virtual const adsk::Data::Associations *	metadata (MStatus *ReturnStatus=NULL) const
	This method is not available in Python. More...
virtual MStatus	setMetadata (const adsk::Data::Associations &)
	This method is not available in Python. More...
virtual MStatus	deleteMetadata ()
	This method is not available in Python. More...
virtual MStatus	validateMetadata (MString &errors) const
	This method is not available in Python. More...
MStatus	dgTimerOn ()
	Indicates that this node should collect DG timing data whenever DG timing is enabled. More...
MStatus	dgTimerOff ()
	Indicates that this node should no longer collect DG timing data when DG timing is enabled. More...
MdgTimerState	dgTimerQueryState (MStatus *ReturnStatus=NULL)
	The function returns the current on/off state of the node's timer. More...
MStatus	dgTimerReset ()
	The function resets the dependency graph timers and counters for this node to zero. More...
double	dgTimer (const MdgTimerMetric timerMetric, const MdgTimerType timerType, MStatus *ReturnStatus=NULL) const
	The function returns the specified timer value for the current node. More...
MStatus	dgCallbacks (const MdgTimerType type, MStringArray &callbackName, MDoubleArray &value)
	Node callbacks that occur when timing is enabled get logged with the node and can be queried via this method. More...
MStatus	dgCallbackIds (const MdgTimerType type, const MString &callbackName, MCallbackIdArray &callbackId, MDoubleArray &value)
	This method provides a further breakdown of the per-callback time returned via dgCallbacks() by returning the data on a per-callbackId basis. More...
MStatus	addAttribute (const MObject &attr, MAttrClass type)
	This method is obsolete. More...
MStatus	removeAttribute (const MObject &attr, MAttrClass type)
	This method is obsolete. More...
Public Member Functions inherited from MFnBase
virtual	~MFnBase ()
	Class Destructor. More...
bool	hasObj (MFn::Type) const
	Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...
bool	hasObj (const MObject &) const
	Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...
MObject	object (MStatus *ReturnStatus=NULL) const
	Returns the MObject that is attached to the Function Set. More...

Protected Member Functions
virtual const char *	className () const
	Class name. More...

Additional Inherited Members
Static Public Member Functions inherited from MFnDependencyNode
static MString	classification (const MString &nodeTypeName)
	Retrieves the classification string for a node type. More...
static unsigned int	allocateFlag (const MString pluginName, MStatus *ReturnStatus=NULL)
	Allocates a node flag for sole use by the caller. More...
static MStatus	deallocateFlag (const MString pluginName, unsigned int flag)
	Deallocates a node flag which was previously allocated by a call to allocateFlag. More...
static MStatus	deallocateAllFlags (const MString pluginName)
	Deallocates all of the node flags which are currently allocated to the specified plugin. More...
static void	enableDGTiming (bool enable)
	Globally enables or disables the DG node timing mechanism. More...
Static Public Member Functions inherited from MFnBase
static const char *	className ()
	Returns the name of this class. More...

Member Enumeration Documentation

enum Form

Forms that a curve may take.

Enumerator
kInvalid
kOpen	Ends are independent.
kClosed	Endpoints are coincident.
kPeriodic	Ends overlap such that there is no break in tangency.
kLast

Constructor & Destructor Documentation

~MFnNurbsCurve ( )

virtual

Destructor.

Class desctructor.

MFnNurbsCurve	(	MObject &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

MFnNurbsCurve	(	const MDagPath &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

Class constructor that initializes the function set to the given constant MDagPath object.

Parameters

[in]	object	The const MDagPath to attach the function set to
[out]	ReturnStatus	The return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

MFnNurbsCurve	(	const MObject &	object,
		MStatus *	ReturnStatus = NULL
	)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

• MS::kSuccess if the function set is successfully attached
• MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

Member Function Documentation

MFn::Type type ( ) const

virtual

Function set type.

Return the class type : MFn::kNurbsCurve.

Reimplemented from MFnDagNode.

const char * className ( ) const

protectedvirtual

Class name.

Return the class name : "MFnNurbsCurve".

Reimplemented from MFnDagNode.

MObject create	(	const MPointArray &	controlVertices,
		const MDoubleArray &	knots,
		unsigned int	degree,
		MFnNurbsCurve::Form	form,
		bool	create2D,
		bool	createRational,
		MObject &	parentOrOwner = MObject::kNullObj,
		MStatus *	ReturnStatus = NULL
	)

This method creates a nurbs curve from the given control vertices and knot vector and sets this function set to operate on the new curve.

The parentOrOwner argument is used to specify the owner of the new curve.

If the parentOrOwner is kNurbsCurveData then the created curve will be of type kNurbsCurveGeom and will be returned. The parentOrOwner will become the owner of the new curve.

If parentOrOwner is NULL then a new transform will be created and returned which will be the parent for the curve. The new transform will be added to the DAG.

If parentOrOwner is a DAG node then the new curve will be returned and the parentOrOwner will become its parent.

The knot vector is valid if it is non-decreasing and of length spans + 2 * degree - 1. The cvs are assumed to be in rational form (as opposed to homogeneous)

If the form specified is kClosed and the endpoints are not close then a new span will be created inorder to close the curve.

Parameters

[in]	controlVertices	an array of control vertices
[in]	knots	an array of knots
[in]	degree	the degree to create the curve with
[in]	form	either kOpen, kClosed, kPeriodic
[in]	create2D	true means that the Z-coordinates of the controlVertices will be ignored, giving a curve in the local XY plane
[in]	createRational	true means curve being created will be rational
[in]	parentOrOwner	the DAG parent or kNurbsCurveData the new curve will belong to
[out]	ReturnStatus	Status code

Returns

• If parentOrOwner is NULL then the transform for this curve is returned
• If parentOrOwner is a DAG object then the curve shape is returned
• The curve geometry is returned if parentOrOwner is of type kNurbsCurveData

Status Codes:

• MS::kSuccess Curve was successfully created
• MS::kInvalidParameter Invalid parameter specified
• MS::kLicenseFailure Application not licensed for attempted operation
• MS::kFailure Error creating curve

Examples:

MObject createWithEditPoints	(	const MPointArray &	editPoints,
		unsigned int	degree,
		MFnNurbsCurve::Form	form,
		bool	create2D,
		bool	createRational,
		bool	uniformParam,
		MObject &	parentOrOwner = MObject::kNullObj,
		MStatus *	ReturnStatus = NULL
	)

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

The parentOrOwner argument is used to specify the owner of the new curve.

If the parentOrOwner is kNurbsCurveData then the created curve will be of type kNurbsCurveGeom and will be returned. The parentOrOwner will become the owner of the new curve.

If parentOrOwner is NULL then a new transform will be created and returned which will be the parent for the curve. The new transform will be added to the DAG.

If parentOrOwner is a DAG node then the new curve will be returned and the parentOrOwner will become its parent.

If the form specified is kClosed and the endpoints are not close then a new span will be created inorder to close the curve.

Parameters

[in]	editPoints	an array of edit points
[in]	degree	the degree to create the curve with
[in]	form	either kOpen, kClosed, kPeriodic
[in]	create2D	true means that the Z-coordinates of the controlVertices will be ignored, giving a curve in the local XY plane
[in]	createRational	true means curve being created will be rational
[in]	uniformParam	true means curve being created will have uniform parameterization, false means chord length
[in]	parentOrOwner	the DAG parent or kNurbsCurveData the new curve will belong to
[out]	ReturnStatus	Status code

Returns

• If parentOrOwner is NULL then the transform for this curve is returned
• If parentOrOwner is a DAG object then the curve shape is returned
• The curve geometry is returned if parentOrOwner is of type kNurbsCurveData

Status Codes:

• MS::kSuccess Curve was successfully created
• MS::kInvalidParameter Invalid parameter specified
• MS::kLicenseFailure Application not licensed for attempted operation
• MS::kFailure Error creating curve

MObject create	(	const MObjectArray &	sources,
		MObject &	parentOrOwner = MObject::kNullObj,
		MStatus *	ReturnStatus = NULL
	)

This method creates a single curve that combines all the curves in the MObjectArray.

The method assumes the curves in the sources are good for building a single curve:

• they are in the same direction,
• they do not intersect themselves or each other,
• there are no gaps between the endpoint of one curve and the start point of the next one in the array.

It is good enough to be C0 continouns (tangent breaks are okay).

Parameters

[in]	sources	Input array of souce curves.
[in]	parentOrOwner	the DAG parent or kNurbsCurveData the new curve will belong to
[out]	ReturnStatus	Status code

Returns

• If parentOrOwner is NULL then the transform for this curve is returned
• If parentOrOwner is a DAG object then the curve shape is returned
• The curve geometry is returned if parentOrOwner is of type kNurbsCurveData

Status Codes:

• MS::kSuccess Curve was successfully created
• MS::kInvalidParameter Invalid parameter specified
• MS::kFailure Error creating curve

MObject copy	(	const MObject &	source,
		MObject &	parentOrOwner = MObject::kNullObj,
		MStatus *	ReturnStatus = NULL
	)

This method creates a copy of a nurbs curve.

The parentOrOwner argument is used to specify the owner of the new curve.

If the parentOrOwner is kNurbsCurveData then the created curve will be of type kNurbsCurveGeom and will be returned. The parentOrOwner will become the owner of the new curve.

If parentOrOwner is NULL then a new transform will be created and returned which will be the parent for the curve. The new transform will be added to the DAG.

If parentOrOwner is a DAG node then the new curve will be returned and the parentOrOwner will become its parent.

Parameters

[in]	source	the curve to be copied
[in]	parentOrOwner	the DAG parent or kNurbsCurveData the new curve will belong to
[out]	ReturnStatus	Status code

Returns

• If parentOrOwner is NULL then the transform for this curve is returned
• If parentOrOwner is a DAG object then the curve shape is returned
• The curve geometry is returned if parentOrOwner is of type kNurbsCurveData

Status Codes:

• MS::kSuccess Curve was successfully created
• MS::kInvalidParameter Invalid parameter specified
• MS::kLicenseFailure Application not licensed for attempted operation
• MS::kFailure Error creating curve

MStatus reverse

(

bool

constructionHistory = false

)

This method reverse the curve direction.

Parameters

[in]

constructionHistory

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.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus 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.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MObject cv	(	unsigned int	index,
		MStatus *	ReturnStatus = NULL
	)		const

Returns a CV as a component.

MItCurveCV can be used to examine or modify the returned CV.

Any modifications to the CV will affect the curve. After all modifications are done, updateCurve should be called to have the curve recalculate its cached geometry.

Parameters

[out]	index	Index of the CV
[out]	ReturnStatus	Status code

Returns

A handle to the CVs requested

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter CV index out of range
• MS::kFailure An object error has occurred

MStatus getCV	(	unsigned int	index,
		MPoint &	pt,
		MSpace::Space	space = MSpace::kObject
	)		const

Get the CV at the given index.

Parameters

[in]	index	The index of the CV that will be retrieved
[out]	pt	Storage for the CV
[in]	space	Specifies the coordinate system for this operation

Returns

Status code

Status Codes:

• MS::kSuccess The CV was successfully set
• MS::kInvalidParameter CV index out of range
• MS::kFailure Object error

MStatus setCV	(	unsigned int	index,
		const MPoint &	pt,
		MSpace::Space	space = MSpace::kObject
	)

Set the CV at the given index to the given point.

The method updateCurve should be called to trigger changes in the curve.

Parameters

[in]	index	The index of the CV that will be changed
[in]	pt	The new value that the CV will take
[in]	space	Specifies the coordinate system for this operation

Returns

Status code

Status Codes:

• MS::kSuccess The CV was successfully set
• MS::kInvalidParameter CV index out of range
• MS::kFailure Object error

MFnNurbsCurve::Form form

(

MStatus *

ReturnStatus = NULL

)

const

This method returns the form of the curve.

The curve can be open, closed, or periodic.

Parameters

[out]

ReturnStatus

Status code

Returns

• MFnNurbsCurve::kOpen
• MFnNurbsCurve::kClosed
• MFnNurbsCurve::kPeriodic

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

int degree

(

MStatus *

ReturnStatus = NULL

)

const

Return the degree of this curve.

If the degree cannot be determined then 0 is returned.

Parameters

[out]

ReturnStatus

Status code

Returns

The degree of this curve.

Status Codes:

• MS::kSuccess The degree was successfully returned.
• MS::kFailure An object error has occurred.

Examples:

int numCVs

(

MStatus *

ReturnStatus = NULL

)

const

Return the number of CVs for this curve.

If the number of CVs cannot be determined then 0 is returned.

Parameters

[out]

ReturnStatus

Status code

Returns

The number of CVs for this curve.

Status Codes:

• MS::kSuccess The number of CVs was successfully returned.
• MS::kFailure An object error has occurred.

Examples:

int numSpans

(

MStatus *

ReturnStatus = NULL

)

const

Return the number of spans for this curve.

If the number of spans cannot be determined then 0 is returned.

Parameters

[out]

ReturnStatus

Status code

Returns

The number of spans for this curve.

Status Codes:

• MS::kSuccess The number of spans was successfully returned.
• MS::kFailure An object error has occurred.

int numKnots

(

MStatus *

ReturnStatus = NULL

)

const

Return the number of knots for this curve.

If the number of knots cannot be determined then 0 is returned.

Parameters

[out]

ReturnStatus

Status code

Returns

The number of knots for this curve.

Status Codes:

• MS::kSuccess The number of knots was successfully returned.
• MS::kFailure An object error has occurred.

MStatus getKnotDomain	(	double &	start,
		double &	end
	)		const

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

Parameters

[out]	start	storage for the max parameter value
[out]	end	storage for the min parameter value

Returns

Status code

Status Codes:

• MS::kSuccess The range was successfully returned
• MS::kFailure Object error

MStatus getKnots

(

MDoubleArray &

array

)

const

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

Parameters

[out]

array

storage where the parameter values of the knots for this curve will be copied

Returns

Status code

Status Codes:

• MS::kSuccess The knots were successfully copied
• MS::kFailure Object error

Examples:

MStatus setKnots	(	const MDoubleArray &	array,
		unsigned int	startIndex,
		unsigned int	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.

Knot indices range from 0 to numKnots() - 1

Parameters

[in]	array	a double array of knot points
[in]	startIndex	the starting index of the knots to be altered.
[in]	endIndex	the ending index of the knots to be altered.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Invalid start or end indices, or the length of the array is not sufficient to fill the range given, or the knots are in decreasing order.
• MS::kFailure An object error has occurred

MStatus setKnot	(	unsigned int	index,
		double	param
	)

Set the given knot's parameter value.

Knot indices range from 0 to numKnots() - 1.

If a knot value is set that breaks the non-decreasing requirement for the knot array, the knot value will be changed and a kInvalidParameter error will be returned.

Parameters

[in]	index	Index of the knot to be set
[in]	param	The parameter value that the knot will take

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Knot index out of range or new knot value breaks the non-decreasing requirement for the knot array.
• MS::kFailure An object error has occurred

MObject cvs	(	unsigned int	startIndex,
		unsigned int	endIndex,
		MStatus *	ReturnStatus = NULL
	)		const

Returns a contiguous group of CVs as a component.

MItCurveCV can be used to examine or modify the returned CVs.

Any modifications to these CVs will affect the curve. After all modifications are done, updateCurve should be called to have the curve recalculate its cached geometry.

Parameters

[in]	startIndex	the start index for the CVs to return
[in]	endIndex	the end index for the CVs to return
[out]	ReturnStatus	Status code

Returns

An MObject providing direct-access to the specified CVs

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter CV index out of range
• MS::kFailure An object error has occurred.

MStatus getCVs	(	MPointArray &	array,
		MSpace::Space	space = MSpace::kObject
	)		const

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

[out]	array	The array of point values for the CVs
[in]	space	Specifies the coordinate system for this operation

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Cannot do world space transform
• MS::kFailure An object error has occurred

Examples:

MStatus setCVs	(	const MPointArray &	array,
		MSpace::Space	space = MSpace::kObject
	)

Set the CVs for this curve to the given points.

Parameters

[in]	array	The array of point values for the CVs
[in]	space	Specifies the coordinate system for this operation

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter Cannot do world space transform.
• MS::kFailure An object error has occurred.

double knot	(	unsigned int	index,
		MStatus *	ReturnStatus = NULL
	)		const

Get the parameter value of the specified knot for this curve.

Knot indices range from 0 to numKnots() - 1

Parameters

[in]	index	The knot index
[out]	ReturnStatus	Status code

Returns

The parameter value for the knot at index.

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Knot index out of range
• MS::kFailure An object error has occurred

MStatus removeKnot	(	double	atThisParam,
		bool	removeAll = false
	)

Remove one or more knots at the given parameter.

If there are multiple knots at the given parameter then removeAll determines the number to be removed. If it is true then they will all be removed. If it is false then all but one will be removed.

Parameters

[in]	atThisParam	Status code
[in]	removeAll	How to handle multiple knots at the same param.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Parameter value is out of range
• MS::kFailure An object error has occurred

bool isPointOnCurve	(	const MPoint &	point,
		double	tolerance = kMFnNurbsEpsilon,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

Determines whether the given point is on this curve.

Parameters

[in]	point	The point to test
[in]	tolerance	The amount of error (epsilon value) in the calculation
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

true if the given point is on the curve, false otherwise.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus getPointAtParam	(	double	param,
		MPoint &	point,
		MSpace::Space	space = MSpace::kObject
	)		const

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

[in]	param	The parameter value that we are examining
[out]	point	Storage for the point being returned
[in]	space	Specifies the coordinate system for this operation

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter Invalid parameter specified.
• MS::kFailure An object error has occurred.

Examples:

MStatus getParamAtPoint	(	const MPoint &	atThisPoint,
		double &	param,
		MSpace::Space	space = MSpace::kObject
	)		const

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

Parameters

[in]	atThisPoint	Point to check
[out]	param	storage for the parameter value
[in]	space	Specifies the coordinate system for this operation

Returns

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus getParamAtPoint	(	const MPoint &	atThisPoint,
		double &	param,
		double	tolerance,
		MSpace::Space	space = MSpace::kObject
	)		const

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

Parameters

[in]	atThisPoint	Point to check
[out]	param	storage for the parameter value
[in]	tolerance	tolerance used for operation
[in]	space	Specifies the coordinate system for this operation

Returns

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

bool isParamOnCurve	(	double	param,
		MStatus *	ReturnStatus = NULL
	)		const

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

Parameters

[in]	param	The parameter value to check
[out]	ReturnStatus	Status code

Returns

• true The parameter is on this curve.
• false Parameter is NOT on this curve.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MVector normal	(	double	param,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

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

[in]	param	The parameter of the point on the curve from which to get the normal
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

The normal vector for the given parameter

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Normal cannot be found for the given parameter value
• MS::kFailure An object error has occurred

Examples:

MVector tangent	(	double	param,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

This method returns the tangent at the given parameter value on the curve.

The resulting tangent vector is normalized.

Parameters

[in]	param	The parameter of the point on the curve from which to get the tangent
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

The tangent vector for the given parameter

Status Codes:

• MS::kSuccess The method was successful
• MS::kInvalidParameter Tangent cannot be found for the given parameter value
• MS::kFailure An object error has occurred

Examples:

MStatus getDerivativesAtParm	(	double	param,
		MPoint &	pos,
		MVector &	dU,
		MSpace::Space	space,
		MVector *	dUU = NULL
	)		const

Evaluate the curve at the given parameter returning the position, first derivative and optionally the second derivative.

Derivatives are not normalized.

Parameters

[in]	param	U parameter value to evaluate
[out]	pos	Storage for the XYZ position of the curve
[out]	dU	Storage for the first order partial derivative with respect to u
[in]	space	Coordinate space for the returned vectors
[out]	dUU	Pointer to storage for the second order partial derivative with respect to u

Returns

Status Code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter Parameter does not define a point on the curve
• MS::kFailure An object error has occurred.

bool isPlanar	(	MVector *	planeNormal = NULL,
		MStatus *	ReturnStatus = NULL
	)		const

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

[in]	planeNormal	Normal to the plane containing this curve
[out]	ReturnStatus	Status code

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MPoint closestPoint	(	const MPoint &	toThisPoint,
		double *	param = NULL,
		double	tolerance = kMFnNurbsEpsilon,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

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

Parameters

[in]	toThisPoint	The point to test
[in]	param	If non-null, on successful returns this will contain the parameter value of the returned point.
[in]	tolerance	The amount of error (epsilon value) to allow in the calculation
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

The point on the curve closest to the given point.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

MPoint closestPoint	(	const MPoint &	toThisPoint,
		bool	paramAsGuess,
		double *	param = NULL,
		double	tolerance = kMFnNurbsEpsilon,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

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

Performance can be greatly increased by supplying a starting parameter value that is reasonably close to the final point.

Parameters

[in]	toThisPoint	The point to test
[in]	paramAsGuess	If true use the incoming 'param' value as a guess as to the location of the closest point. If the closest point lies within the same span as the guess then this can greatly speed up the search. If not then the search may be slowed a bit.
[in,out]	param	pointer to a double. If non-null, on successful returns this will contain the parameter value of the returned point.
[in]	tolerance	The amount of error (epsilon value) in the calculation
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

The point on the curve closest to the given point.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

double distanceToPoint	(	const MPoint &	pt,
		MSpace::Space	space = MSpace::kObject,
		MStatus *	ReturnStatus = NULL
	)		const

Returns the distance from the given point to the point on the curve which is closest to it.

Parameters

[in]	pt	The point to calculate the distance to
[in]	space	Specifies the coordinate system for this operation
[out]	ReturnStatus	Status code

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

double area	(	double	tolerance = kMFnNurbsEpsilon,
		MStatus *	ReturnStatus = NULL
	)		const

This method returns the area bounded by this curve.

The curve must be closed and planar.

A value of 0.0 will be returned if area cannot be determined.

Parameters

[in]	tolerance	The amount of error (epsilon value) in the calculation
[out]	ReturnStatus	Status code

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

double length	(	double	tolerance = kMFnNurbsEpsilon,
		MStatus *	ReturnStatus = NULL
	)		const

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

Parameters

[in]	tolerance	The amount of error (epsilon value) in the calculation
[out]	ReturnStatus	Status code

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

Examples:

double findParamFromLength	(	double	partLength,
		MStatus *	ReturnStatus = NULL
	)		const

Returns the parameter value corresponding to a given length along the curve.

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

[in]	partLength	Length along the curve to find parameter value at
[out]	ReturnStatus	Status code

Returns

The parameter value corresponding to the given length. If a parameter cannot be found for the given length then the parameter for the end point of the curve is returned.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter Parameter value cannot be found
• MS::kFailure An object error has occurred.

Examples:

double findLengthFromParam	(	double	param,
		MStatus *	ReturnStatus = NULL
	)		const

Returns the length along the curve corresponding to a given parameter value on the curve.

If the length cannot be found for the given parameter value then ReturnStatus is set to kInvalidParameter and a length of zero is returned.

Parameters

[in]	param	Parameter value on the curve
[out]	ReturnStatus	Status code

Returns

The length corresponding to the given parameter value. If the given parameter value cannot be found then a length of zero is returned.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kInvalidParameter length cannot be determined
• MS::kFailure An object error has occurred.

bool hasHistoryOnCreate

(

MStatus *

ReturnStatus = NULL

)

const

This method determines if the shape was created with history.

If the object that this function set is attached to is not a shape then this method will fail.

Parameters

[out]

ReturnStatus

Returns

• true shape has history
• false shape does not have history

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MStatus updateCurve

(

)

This method signals that this curve has changed and needs to be recalculated.

This method is useful when a large number of CVs for the curve are being modified. Instead of updating the curve every time a CV is changed it is more efficient to call this method once after updating all of the CVs.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An object error has occurred.

MObject rebuild	(	unsigned int	spans,
		unsigned int	degree = 3,
		unsigned int	keepRange = 1,
		unsigned int	endKnots = 0,
		bool	keepEndPoints = true,
		bool	keepTangents = true,
		bool	keepControlPoints = false,
		float	tolerance = 0.01f,
		MStatus *	ReturnStatus = NULL
	)		const

This method rebuilds a new curve based on the current curve and parameters.

This method does not change current curve, but put the newly rebuilt curve data inside a MFnNurbsCurveData and then return it back.

This method is useful when you want to use Maya native algorithm to do nurbs curve rebuilding.

It uses same algorithm and similar controls as command 'rebuildCurve'.

Parameters

[in]	spans	The number of spans in resulting curve
[in]	degree	The degree of the resulting curve 1 - linear, 2 - quadratic, 3 - cubic, 5 - quintic, 7 - heptic
[in]	keepRange	Determine the parameterization for the resulting curve. 0 - reparameterize the resulting curve from 0 to 1, 1 - keep the original curve parameterization, 2 - reparameterize the result from 0 to number of spans
[in]	endKnots	End conditions for the curve 0 - uniform end knots, 1 - multiple end knots
[in]	keepEndPoints	If true, keep the endpoints the same
[in]	keepTangents	If true, keep the end tangents the same
[in]	keepControlPoints	If true, the CVs will remain the same.
[in]	tolerance	The tolerance with which to rebuild
[out]	ReturnStatus	Status code

Returns

• The new MObject containing the rebuilt curve

Status Codes:

• MS::kSuccess Curve was successfully rebuilt
• MS::kInvalidParameter Invalid parameter specified
• MS::kFailure Error rebuilding curve

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The documentation for this class was generated from the following files:

• MFnNurbsCurve.h
• MFnNurbsCurve.cpp