pymel.core.general.isDirty

isDirty(*args, **kwargs)

The isDirtycommand is used to check if a plug is dirty. The return value is 0 if it is not and 1 if it is. If more than one plug is specified then the result is the logical “or” of all objects (ie. returns 1 if *any* of the plugs are dirty).

Flags:

Long name (short name)		Argument Types	Properties
connection (c)		bool
	Check the connection of the plug (default).Flag can appear in Create mode of commandFlag can have multiple arguments, passed either as a tuple or a list.
datablock (d)		bool
	Check the datablock entry for the plug.

Derived from mel command maya.cmds.isDirty

Example:

import pymel.core as pm

# Create a plusMinusAverage node and a transform. We set the 'skipSelect'
# flag so that they are not displayed in the Attribute Editor because
# that would force an evaluation and cause the plugs to become clean.
import maya.cmds as cmds
pm.createNode('plusMinusAverage', n='pma', skipSelect=True)
# Result: nt.PlusMinusAverage(u'pma') #
pm.createNode('transform', n='t', skipSelect=True)
# Result: nt.Transform(u't') #

# Hide the transform so that Maya's draw won't force an evaluation which
# would clean its plugs.
pm.hide('t')

# Connect the transform's 'tx' to one of the plusMinusAverage node's
# inputs.
pm.connectAttr('t.tx', 'pma.input1D[0]')

# Set the value of the transform's 'tx' and check that the
# target of the connection has become dirty.
pm.setAttr('t.tx', 13)
pm.isDirty('pma.input1D[0]')
# Result: True #

# If we retrieve the value of the destination attribute
# then the connection becomes clean.
pm.getAttr('pma.input1D[0]')
# Result: 13.0 #
pm.isDirty('pma.input1D[0]')
# Result: False #

# A plusMinusAverage node's 'output1D' attribute depends
# upon the values in its 'input1D' array. Since we haven't
# retrieved its value yet, it should still be dirty. However,
# it seems to be clean:
pm.isDirty('pma.output1D')
# Result: False #

# The reason for this is that the 'isDirty' command
# by default only checks connections and 'output1D' has
# no connection to be dirty. If we instead check its
# value in the datablock, we get the expected result:
pm.isDirty('pma.output1D', d=True)
# Result: True #

# The output value will remain dirty until we
# force its evaluation by retrieving it.
pm.getAttr('pma.output1D')
# Result: 13.0 #
pm.isDirty('pma.output1D', d=True)
# Result: False #