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This is the expression node. It takes an arbitrary list of doubles as input and performs any legal MEL expression on them to generate a list of double outputs.

Caution: Use of the 'setAttr' or 'getAttr' statements from within an expression node can have unexpected results. Using these statements bypasses the normal dependency graph evaluation mechanism and may cause incorrect or incomplete evaluation.

Node nameParentsClassificationMFn typeCompatible function sets
expressionnodemathkExpressionkBase
kNamedObject
kDependencyNode
kExpression

Related nodes

animCurve, animCurveUT, animCurveUU, animCurveUA, animCurveTT, animCurveTU, animCurveUL, resultCurve, resultCurveTimeToLinear, resultCurveTimeToTime, resultCurveTimeToUnitless, resultCurveTimeToAngular, animCurveTA, animCurveTL, animBlend, animBlendInOut

Attributes (15)

animated, attribute, evaluateNow, exprConnCount, expression, frame, input, internalExpression, lastTimeEvaluated, newFileFormat, object, objectMsg, output, time, unitOption

Long name (short name)TypeDefaultFlags
input (in) double0.0arrayoutputinputconnectablestorable
This is the multi that holds the connection as input into the expression.
output (out) double0.0arrayoutputinputconnectable
This is the multi that holds the connection as output of the expression.
object (ob) stringNULLoutputconnectablehidden
Default object for attribute names in expression.
attribute (a) stringNULLoutputinputconnectablehidden
Default attribute if no lvalue in expression
expression (e) stringNULLoutputinputconnectablehidden
Evaluated value of the expression
exprConnCount (xcc) integer0outputconnectablehidden
number of input and output connections for expressions
internalExpression (ixp) stringNULLoutputinputconnectablestorablehidden
This is the internal representation for the expression.
time (tim) time0filmoutputinputconnectablehidden
This holds the value for time to be queried in seconds.
frame (frm) time0filmoutputinputconnectablehidden
This holds the value for time to be queried in frames.
lastTimeEvaluated (lte) time0filmoutputinputconnectablehidden
The last time that this expression was evaluated.
evaluateNow (xen) short0outputconnectablehidden
This attribute depends on aTime. Dirtying aTime and asking for this will force evaluation.
animated (ani) enum1outputinputconnectablestorablehidden
This attribute tells whether or not the expression node was forced to be "animated" from the expression command. Records the unit conversion option used to create/edit this expression.
newFileFormat (nff) short0outputconnectablehidden
Obsolete.
objectMsg (obm) Messagen/aoutputinputconnectablehidden
Identifies the default object.
unitOption (uno) enum0outputinputconnectablestorablehidden
Records the unit conversion option used to create/edit this expression.