MFnClip Class Reference

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Detailed Description

clip function set

Maya uses animation clips as the building block of its nonlinear animation system, "Trax". An animation clip allows the user to bundle a set of animation curves independent of time so that they can be reused multiple times, with different timing then the original clip.

Character sets (MFnCharacter) are integral to Maya's clip architecture, since a clip contains whatever attributes of the character were animated when the clip was created. For more information on character sets, refer to the MFnCharacter documentation.

Clips in maya can be of two types: source clips and scheduled clips. In the Maya UI, source clips are visible in the Visor while scheduled clips are visible in Trax. A source clip contains the animation curves for the clip. A scheduled clip contains data about the placement of an instance of a source clip in the Maya timeline. In this context, an "instance" means that the animation curves from the source clip are shared by the scheduled clip. Scheduled clips never contain their own animation curves, they always refer to a source clip's curves.

For example, if you create a clip called "run" in maya that lasts from frames 1-20, a source clip node will be created with a start of 1, a duration of 19, and dependency graph connections to all of the animation curves that make up the "run". If you then place an instance of the run clip at frame 5 and another instance of the run clip at frame 20, you have 2 scheduled clips: one with a start frame of 5 and one with a start frame of 20. As mentioned in the previous paragraph, only a single set of animation curves exist for the run regardless of the number of times the run is scheduled.

Trax also allows you to create "blends" between clips, which enable you to control the transition between the clips. A blend is represented in the dependency graph by an "animBlendInOut" node, which uses an animation curve to determine the transition type.

In the dependency graph, when a character has animation clips, the character node will always be connected to a "clipLibrary" node and a "clipScheduler" node. The clipLibrary node is connected to all of the source clips and their animation curves. The clipScheduler node is connected to the scheduled clips and blends. It is the clipScheduler that computes the final animation by looking at the placement and overlap of the clips and feeding the attribute data back into the character set.

To create a source clip, the typical steps are:

1. If the attributes are not already in a character, create a character containing the attributes.
2. Create a source clip using MFnClip::createSourceClip
3. Attach the clip to a character using MFnCharacter::attachSourceToCharacter
4. Attach animation curves to the clip using MFnCharacter::addCurveToClip

To create a scheduled clip so that it appears in the Trax Editor, the typical steps are:

1. Create an instanced animClip node using MFnClip::createInstancedClip, and associate it with the source clip that you want to instance.
2. Attach the clip instance to the character using MFnCharacter::attachInstanceToCharacter

Examples:

createClipCmd.cpp.

#include <MFnClip.h>

Inheritance diagram for MFnClip:

List of all members.

Public Member Functions
virtual MFn::Type	type () const
	Function set type.
virtual	~MFnClip ()
	Destructor.
	MFnClip ()
	Default constructor.
	MFnClip (MObject &object, MStatus *ReturnStatus=NULL)
	Constructor.
MObject	createSourceClip (const MTime &sourceStart, const MTime &sourceDuration, MDGModifier &dgMod, MStatus *ReturnStatus=NULL)
	Creates a source clip node and associates it with this function set.
MObject	createInstancedClip (MObject &sourceClip, const MTime &start, MDGModifier &dgMod, MStatus *ReturnStatus=NULL, bool absolute=1, double postCycle=0.0, double weight=1.0, double scale=1.0, double preCycle=0.0)
	Creates an instance of a clip that will be viewable in the Trax editor.
bool	isInstancedClip (MStatus *ReturnStatus=NULL)
	Return true or false as to whether the clip node represents the source clip or an instanced clip.
bool	isPose (MStatus *ReturnStatus=NULL)
	Return true or false as to whether the clip node represents a pose.
MObject	sourceClip (MStatus *ReturnStatus=NULL)
	Return the source clip associated with the MFnClip's clip.
double	getPreCycle (MStatus *ReturnStatus=NULL)
	Return the value of this clip's pre cycle attribute.
double	getPostCycle (MStatus *ReturnStatus=NULL)
	Return the value of this clip's post cycle attribute.
double	getCycle (MStatus *ReturnStatus=NULL)
	This method is obsolete.
double	getWeight (MStatus *ReturnStatus=NULL)
	Return the value of this clip's weight attribute.
double	getScale (MStatus *ReturnStatus=NULL)
	Return the value of this clip's scale attribute.
bool	getAbsolute (MStatus *ReturnStatus=NULL)
	This method is obsolete.
bool	getEnabled (MStatus *ReturnStatus=NULL)
	Return the value of this clip's enable attribute.
MTime	getStartFrame (MStatus *ReturnStatus=NULL)
	Return the value of this clip's start frame.
MTime	getSourceStart (MStatus *ReturnStatus=NULL)
	Return the value of the start frame of this clip's source clip.
MTime	getSourceDuration (MStatus *ReturnStatus=NULL)
	Return the value of the start frame of this clip's source duration.
MStatus	getMemberAnimCurves (MObjectArray &curves, MPlugArray &associatedAttrs)
	Return two arrays: the first contains the animCurves associated with this clip.
MStatus	getAbsoluteChannelSettings (MIntArray &absoluteChannels)
	Return an array indicating which channels of the clip are absolute and which are relative.
int	getTrack (MStatus *ReturnStatus=NULL)
	Return the track number for the clip.
MStatus	setPoseClip (bool state, MDGModifier *mod=NULL)
	Specify whether or not this clip node should be tagged as a pose rather than a clip.
MStatus	setPreCycle (double cycle, MDGModifier *mod=NULL)
	Specify the pre cycle value for the clip.
MStatus	setPostCycle (double cycle, MDGModifier *mod=NULL)
	Specify the post cycle value for the clip.
MStatus	setCycle (double cycle, MDGModifier *mod=NULL)
	This method is obsolete.
MStatus	setWeight (double wt, MDGModifier *mod=NULL)
	Specify a weight value for the clip.
MStatus	setScale (double scale, MDGModifier *mod=NULL)
	Specify a scale value for the clip.
MStatus	setAbsolute (bool abs, MDGModifier *mod=NULL)
	This method is obsolete.
MStatus	setEnabled (bool val, MDGModifier *mod=NULL)
	Specify whether or not the clip is enabled.
MStatus	setStartFrame (const MTime &start, MDGModifier *mod=NULL)
	Specify the start frame for the instanced clip.
MStatus	setSourceData (const MTime &start, const MTime &duration, MDGModifier *mod=NULL)
	Specify the start frame and duration for the source clip associated with this clip.
MStatus	setTrack (int index, MDGModifier *mod=NULL)
	Specify the one-based track number for the clip.
MStatus	setAbsoluteChannelSettings (const MIntArray &absoluteChannels, MDGModifier *mod=NULL)
	Set which channels of the clip are absolute and which are relative.
	MFnClip (const MObject &object, MStatus *ReturnStatus=NULL)
	Constructor.
Protected Member Functions
virtual const char *	className () const
	Class name.

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Constructor & Destructor Documentation

MFnClip	(	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

MFnClip	(	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

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Member Function Documentation

MFn::Type type

(

)

const [virtual]

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Function set type.

Return the class type : MFn::kClip.

Reimplemented from MFnDependencyNode.

const char * className

(

)

const [protected, virtual]

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Class name.

Return the class name : "MFnClip".

Reimplemented from MFnDependencyNode.

MObject createSourceClip	(	const MTime &	sourceStart,
		const MTime &	sourceDuration,
		MDGModifier &	dgMod,
		MStatus *	ReturnStatus = NULL
	)

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Creates a source clip node and associates it with this function set.

Each animation clip has a single source clip, which defines the startFrame and duration of the clip's animation curves. The startFrame and duration act as a window onto the animation curves, defining the range of animation that is considered part of the clip. After a source clip node is created, it can be passed to a MFnCharacter along with the clip animCurves in order to associate the clip with the character.

Parameters:

[in]	sourceStart	time on clip animCurves that represents clip start
[in]	sourceDuration	time extent of the clip
[in]	dgMod	command modifier used for undo and redo
[out]	ReturnStatus	return status

Returns:

The newly created clip.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure operation failed
• MS::kInsufficientMemory out of memory

Examples:

createClipCmd.cpp.

MObject createInstancedClip	(	MObject &	sourceClip,
		const MTime &	start,
		MDGModifier &	dgMod,
		MStatus *	ReturnStatus = NULL,
		bool	absolute = 1,
		double	postCycle = 0.0,
		double	weight = 1.0,
		double	scale = 1.0,
		double	preCycle = 0.0
	)

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Creates an instance of a clip that will be viewable in the Trax editor.

Parameters:

[in]	sourceClip	the source clip node
[in]	start	start frame where the instance will be scheduled
[in]	dgMod	command modifier used for undo and redo
[in]	ReturnStatus	return status
[in]	absolute	whether the clip is absolute (1) or relative (0)
[in]	preCycle	pre cycle for the clip
[in]	postCycle	post cycle for the clip
[in]	weight	weight for the clip
[in]	scale	scale for the clip

Returns:

The newly created clip.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure invalid source clip was provided
• MS::kInsufficientMemory out of memory

Examples:

createClipCmd.cpp.

bool isInstancedClip

(

MStatus *

ReturnStatus = NULL

)

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Return true or false as to whether the clip node represents the source clip or an instanced clip.

All clips maintained by the clipScheduler node and visible in the TraX editor are instanced clips. All clips maintained by the clipLibrary node and visible in the Visor are non-instanced clips, also called "Source Clips". Each instanced clip has a corresponding source clip.

Parameters:

[out]

ReturnStatus

return status

Returns:

True or false as to whether the clip is an instanced clip.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

bool isPose

(

MStatus *

ReturnStatus = NULL

)

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Return true or false as to whether the clip node represents a pose.

Parameters:

[out]

ReturnStatus

return status

Returns:

True or false as to whether the clip is a pose.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MObject sourceClip

(

MStatus *

ReturnStatus = NULL

)

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Return the source clip associated with the MFnClip's clip.

Parameters:

[out]

ReturnStatus

return status

Returns:

MObject containing the associated source clip.

Status Codes:

• MS::kSuccess operation successful
• MS::kObjectDoesNotExist this clip does not have an associated source clip
• MS::kFailure this function set does not have a valid clip object

double getPreCycle

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's pre cycle attribute.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's pre cycle attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

double getPostCycle

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's post cycle attribute.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's post cycle attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

double getCycle

(

MStatus *

ReturnStatus = NULL

)

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This method is obsolete.

Deprecated:

Use the method MFnClip::getPostCycle instead.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's cycle attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

double getWeight

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's weight attribute.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's weight attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

double getScale

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's scale attribute.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's scale attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

bool getAbsolute

(

MStatus *

ReturnStatus = NULL

)

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This method is obsolete.

Deprecated:

Use the method MFnClip::getAbsoluteChannelSettings instead.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's offset attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

bool getEnabled

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's enable attribute.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's enable attribute.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MTime getStartFrame

(

MStatus *

ReturnStatus = NULL

)

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Return the value of this clip's start frame.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's start frame.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MTime getSourceStart

(

MStatus *

ReturnStatus = NULL

)

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Return the value of the start frame of this clip's source clip.

The sourceStart and sourceDuration define the region of the animCurve that is treated as the clip.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's source start frame.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object
• MS::kObjectDoesNotExist this clip does not have an associated source clip

MTime getSourceDuration

(

MStatus *

ReturnStatus = NULL

)

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Return the value of the start frame of this clip's source duration.

The sourceStart and sourceDuration define the region of the animCurve that is treated as the clip.

Parameters:

[out]

ReturnStatus

return status

Returns:

The value of this clip's source duration.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object
• MS::kObjectDoesNotExist this clip does not have an associated source clip

MStatus getMemberAnimCurves	(	MObjectArray &	curves,
		MPlugArray &	associatedAttrs
	)

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Return two arrays: the first contains the animCurves associated with this clip.

The second contains the character member that is driven by this animCurve.

Parameters:

[out]	curves	array to store the result curves
[out]	associatedAttrs	array to store the character members

Returns:

Return status

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object
• MS::kObjectDoesNotExist this clip does not have an associated source clip

MStatus getAbsoluteChannelSettings

(

MIntArray &

absoluteChannels

)

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Return an array indicating which channels of the clip are absolute and which are relative.

The length of the array is equal to the members in the character. A value of one in the array indicates absolute and a value of 0 indicates relative.

Parameters:

[out]

absoluteChannels

array to store the result

Returns:

Return status

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

int getTrack

(

MStatus *

ReturnStatus = NULL

)

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Return the track number for the clip.

Track indices are one-based. If a track index of zero is returned, it indicates that a track has not yet been assigned to the clip.

Parameters:

[out]

ReturnStatus

return status

Returns:

The index of this clip's track

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this clip is a source clip and does not have a track
• MS::kObjectDoesNotExist this function set does not have a valid clip object

MStatus setPoseClip	(	bool	state,
		MDGModifier *	mod = NULL
	)

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Specify whether or not this clip node should be tagged as a pose rather than a clip.

By default, clip nodes are not poses.

Parameters:

[in]	state	true, to tag the clip as a pose
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setPreCycle	(	double	cycle,
		MDGModifier *	mod = NULL
	)

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Specify the pre cycle value for the clip.

Parameters:

[in]	cycle	cycle value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setPostCycle	(	double	cycle,
		MDGModifier *	mod = NULL
	)

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Specify the post cycle value for the clip.

Parameters:

[in]	cycle	cycle value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setCycle	(	double	cycle,
		MDGModifier *	mod = NULL
	)

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This method is obsolete.

Deprecated:

Use the method MFnClip::setPostCycle instead.

Parameters:

[in]	cycle	cycle value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setWeight	(	double	wt,
		MDGModifier *	mod = NULL
	)

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Specify a weight value for the clip.

Parameters:

[in]	wt	weight value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setScale	(	double	scale,
		MDGModifier *	mod = NULL
	)

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Specify a scale value for the clip.

Parameters:

[in]	scale	scale value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setAbsolute	(	bool	abs,
		MDGModifier *	mod = NULL
	)

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This method is obsolete.

Deprecated:

Use the method MFnClip::setAbsoluteChannelSettings instead.

Parameters:

[in]	abs	true if absolute, false if relative
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setEnabled	(	bool	val,
		MDGModifier *	mod = NULL
	)

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Specify whether or not the clip is enabled.

Note: should not be called for source clips since the enabled attribute is ignored on source clips.

Parameters:

[in]	val	enable value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setStartFrame	(	const MTime &	start,
		MDGModifier *	mod = NULL
	)

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Specify the start frame for the instanced clip.

Note: should not be called for source clips since the start frame attribute is ignored on source clips.

Parameters:

[in]	start	start frame value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object

MStatus setSourceData	(	const MTime &	start,
		const MTime &	duration,
		MDGModifier *	mod = NULL
	)

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Specify the start frame and duration for the source clip associated with this clip.

Parameters:

[in]	start	source start frame value
[in]	duration	source duration value
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status.

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object
• MS::kObjectDoesNotExist this clip does not have an associated source clip

MStatus setTrack	(	int	trackIndex,
		MDGModifier *	mod = NULL
	)

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Specify the one-based track number for the clip.

Parameters:

[in]	trackIndex	the track number for the clip
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status

Status Codes:

• MS::kSuccess operation successful
• MS::kFailure this function set does not have a valid clip object
• MS::kObjectDoesNotExist clip track value cannot be set

MStatus setAbsoluteChannelSettings	(	const MIntArray &	absoluteChannels,
		MDGModifier *	mod = NULL
	)

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Set which channels of the clip are absolute and which are relative.

The length of the specified array should be equal to the number of members in the character. A value of one in the array indicates absolute and a value of 0 indicates relative.

Parameters:

[in]	absoluteChannels	array containing the absolute channels to be set
[in]	mod	modifier to use when calling this method from commands that support undo

Returns:

Return status

Status Codes:

• MS::kSuccess operation successful
• MS::kObjectDoesNotExist this function set does not have a valid clip object