pymel.core.general.addExtension

addExtension(*args, **kwargs)

This command is used to add an extension attribute to a node type. Either the longName or the shortName or both must be specified. If neither a dataType nor an attributeType is specified, a double attribute will be added. The dataType flag can be specified more than once indicating that any of the supplied types will be accepted (logical-or). To add a non- double attribute the following criteria can be used to determine whether the dataType or the attributeType flag is appropriate. Some types, such as double3can use either. In these cases the -dtflag should be used when you only wish to access the data as an atomic entity (eg. you never want to access the three individual values that make up a double3). In general it is best to use the -atin these cases for maximum flexibility. In most cases the -dtversion will not display in the attribute editor as it is an atomic type and you are not allowed to change individual parts of it. All attributes flagged as “(compound)” below or the compound attribute itself are not actually added to the node until all of the children are defined (using the “-p” flag to set their parent to the compound being created). See the EXAMPLES section for more details. Type of attributeFlag and argument to useboolean-at bool32 bit integer-at long16 bit integer- at short8 bit integer-at bytechar-at charenum-at enum (specify the enum names using the enumName flag)float-at “float” (use quotes since float is a mel keyword)double-at doubleangle value-at doubleAnglelinear value-at doubleLinearstring-dt “string” (use quotes since string is a mel keyword)array of strings-dt stringArraycompound-at compoundmessage (no data)-at messagetime-at time4x4 double matrix-dt “matrix” (use quotes since matrix is a mel keyword)4x4 float matrix-at fltMatrixreflectance-dt reflectanceRGBreflectance (compound)-at reflectancespectrum-dt spectrumRGBspectrum (compound)-at spectrum2 floats-dt float22 floats (compound)-at float23 floats-dt float33 floats (compound)-at float32 doubles-dt double22 doubles (compound)-at double23 doubles-dt double33 doubles (compound)-at double32 32-bit integers-dt long22 32-bit integers (compound)-at long23 32-bit integers-dt long33 32-bit integers (compound)-at long32 16-bit integers-dt short22 16-bit integers (compound)-at short23 16-bit integers-dt short33 16-bit integers (compound)-at short3array of doubles-dt doubleArrayarray of 32-bit ints-dt Int32Arrayarray of vectors-dt vectorArraynurbs curve-dt nurbsCurvenurbs surface-dt nurbsSurfacepolygonal mesh-dt meshlattice-dt latticearray of double 4D points-dt pointArray

Flags:

Long name (short name)		Argument Types	Properties
attributeType (at)		unicode
	Specifies the attribute type, see above table for more details. Note that the attribute types “float”, “matrix” and “string” are also MEL keywords and must be enclosed in quotes.
binaryTag (bt)		unicode
	This flag is obsolete and does not do anything any more
cachedInternally (ci)		bool
	Whether or not attribute data is cached internally in the node. This flag is currently not supported (it will always be set to a default value of true).
category (ct)		unicode
	An attribute category is a string associated with the attribute to identify it. (e.g. the name of a plugin that created the attribute, version information, etc.) Any attribute can be associated with an arbitrary number of categories however categories can not be removed once associated.
dataType (dt)		unicode
	Specifies the data type. See “setAttr” for more information on data type names.
defaultValue (dv)		float
	Specifies the default value for the attribute (can only be used for numeric attributes).
enumName (en)		unicode
	Flag used to specify the ui names corresponding to the enum values. The specified string should contain a colon-separated list of the names, with optional values. If values are not specified, they will treated as sequential integers starting with 0. For example: -enumName “A:B:C” would produce options: A,B,C with values of 0,1,2; -enumName “zero:one:two:thousand=1000” would produce four options with values 0,1,2,1000; and -enumName “solo=1:triplet=3:quintet=5” would produce three options with values 1,3,5. (Note that there is a current limitation of the Channel Box that will sometimes incorrectly display an enumerated attribute’s pull-down menu. Extra menu items can appear that represent the numbers inbetween non-sequential option values. To avoid this limitation, specify sequential values for the options of any enumerated attributes that will appear in the Channel Box. For example: “solo=1:triplet=2:quintet=3”.)
exists (ex)		bool
	Returns true if the attribute queried is a user-added, dynamic attribute; false if not.Flag can appear in Create mode of commandFlag can have multiple arguments, passed either as a tuple or a list.
fromPlugin (fp)		bool
	Was the attribute originally created by a plugin? Normally set automatically when the API call is made - only added here to support storing it in a file independently from the creating plugin.
hasMaxValue (hxv)		bool
	Flag indicating whether an attribute has a maximum value. (can only be used for numeric attributes).
hasMinValue (hnv)		bool
	Flag indicating whether an attribute has a minimum value. (can only be used for numeric attributes).
hasSoftMaxValue (hsx)		bool
	Flag indicating whether a numeric attribute has a soft maximum.
hasSoftMinValue (hsn)		bool
	Flag indicating whether a numeric attribute has a soft minimum.
hidden (h)		bool
	Will this attribute be hidden from the UI?
indexMatters (im)		bool
	Sets whether an index must be used when connecting to this multi-attribute. Setting indexMatters to false forces the attribute to non-readable.
internalSet (internalSet)		bool
	Whether or not the internal cached value is set when this attribute value is changed. This is an internal flag used for updating UI elements.
keyable (k)		bool
	Is the attribute keyable by default?
longName (ln)		unicode
	Sets the long name of the attribute.
maxValue (max)		float
	Specifies the maximum value for the attribute (can only be used for numeric attributes).
minValue (min)		float
	Specifies the minimum value for the attribute (can only be used for numeric attributes).
multi (m)		bool
	Makes the new attribute a multi-attribute.
niceName (nn)		unicode
	Sets the nice name of the attribute for display in the UI. Setting the attribute’s nice name to a non-empty string overrides the default behaviour of looking up the nice name from Maya’s string catalog. (Use the MEL commands “attributeNiceName” and “attributeQuery -niceName” to lookup an attribute’s nice name in the catalog.)
nodeType (nt)		unicode
	Specifies the type of node to which the attribute will be added. See the nodeType command for the names of different node types.
numberOfChildren (nc)		int
	How many children will the new attribute have?
parent (p)		unicode
	Attribute that is to be the new attribute’s parent.
readable (r)		bool
	Can outgoing connections be made from this attribute?
shortName (sn)		unicode
	Sets the short name of the attribute.
softMaxValue (smx)		float
	Soft maximum, valid for numeric attributes only. Specifies the upper default limit used in sliders for this attribute.
softMinValue (smn)		float
	Soft minimum, valid for numeric attributes only. Specifies the upper default limit used in sliders for this attribute.
storable (s)		bool
	Can the attribute be stored out to a file?
usedAsColor (uac)		bool
	Is the attribute to be used as a color definition? Must have 3 DOUBLE or 3 FLOAT children to use this flag. The attribute type “-at” should be “double3” or “float3” as appropriate. It can also be used to less effect with data types “-dt” as “double3” or “float3” as well but some parts of the code do not support this alternative. The special attribute types/data “spectrum” and “reflectance” also support the color flag and on them it is set by default.
usedAsFilename (uaf)		bool
	Is the attribute to be treated as a filename definition? This flag is only supported on attributes with data type “-dt” of “string”.
writable (w)		bool
	Can incoming connections be made to this attribute?

Derived from mel command maya.cmds.addExtension

Example:

import pymel.core as pm

import maya.cmds as cmds

# Add an attribute named ms/mass with a default value of 1 and a
# minimum value of 0.001 and a maximum of 10000 to all mesh shapes.
#
pm.addExtension( nodeType='mesh', shortName='ms', longName='mass', defaultValue=1.0, minValue=0.001, maxValue=10000 )
# Add a multi attribute named ff/forcefield of type double3 to all mesh shapes.
#
pm.addExtension( nodeType='mesh', shortName='ff', longName='forcefield', dataType='double3', multi=True )
# Add a compound attribute named sampson with children homeboy, midge,
# damien, elizabeth, and sweetpea of varying types to all choice nodes.
#
pm.addExtension( nodeType='choice', longName='sampson', numberOfChildren=5, attributeType='compound' )
pm.addExtension( nodeType='choice', longName='homeboy', attributeType='matrix', parent='sampson' )
pm.addExtension( nodeType='choice', longName='midge', attributeType='message', parent='sampson' )
pm.addExtension( nodeType='choice', longName='damien', attributeType='double', parent='sampson' )
pm.addExtension( nodeType='choice', longName='elizabeth', attributeType='double', parent='sampson' )
pm.addExtension( nodeType='choice', longName='sweetpea', attributeType='double', parent='sampson' )
# To add an attribute that is to be interpreted as a color the
# following attribute group must be used.
#
# Note that the word "float" must be in quotations since it is a
# MEL keyword.
#
pm.addExtension( nodeType='phong', longName='rainbow', usedAsColor=True, attributeType='float3' )
pm.addExtension( nodeType='phong', longName='redBow', attributeType='float', parent='rainbow' )
pm.addExtension( nodeType='phong', longName='greenBow', attributeType='float', parent='rainbow' )
pm.addExtension( nodeType='phong', longName='blueBow', attributeType='float', parent='rainbow' )
# Other legal attribute types that can be interpreted as colors need
# not specify the "-usedAsColor" flag as it will be assumed.  These
# include "-attributeType spectrum", "-attributeType reflectance",
# "-dataType spectrumRGB", and "-dataType reflectanceRGB".
#
pm.addExtension( nodeType='phong', longName='implColor', dataType='spectrumRGB' )
# Add a double3 attribute named sanders with children bess, les and wes
# to all dag nodes, including shapes, transforms, and joints.
#
pm.addExtension( nodeType='dagNode', longName='sanders', attributeType='double3' )
pm.addExtension( nodeType='dagNode', longName='bess', attributeType='double', parent='sanders' )
pm.addExtension( nodeType='dagNode', longName='les', attributeType='double', parent='sanders' )
pm.addExtension( nodeType='dagNode', longName='wes', attributeType='double', parent='sanders' )