aimConstraint

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This node implements an aimConstraint. Each constraint has a set of targets that are connected under the target attribute, a single constrained object that is connected to the constraint* attributes, and possibly other information to help compute the correct results. In the case of the aimConstraint, the additional information is: aimVector, upVector, worldUpVector, worldUpMatrix, and worldUpType.

The aimConstraint node can have any number of target inputs. Each target is connected to attributes inside a single element of the target attribute. For example, the first target object would be connected elements of target[0], the second target object would be connected to elements of target[1], etc. The elements of each target are: targetTranslate, targetRotatePivot, targetRotateTranslate, targetParentMatrix, and targetWeight.

The elements of each target are normally connected to the target objects as follows:

aimConstraint attribute	connected to
targetTranslate	translate
targetRotatePivot	rotatePivot
targetRotateTranslate	rotatePivotTranslate
targetParentMatrix	parentMatrix[i]
targetWeight	set to 1.0

The targetWeight attribute is not generally connected to the target object. Instead, it may be animated by other means to adjust the weighted average computation for the target point.

The aimConstraint node uses these inputs to compute the world space position of the pivot point of each target object. It then computes a weighted average of the these pivot points. This weighted average is called the target point.

The constrained object is connected to the constraint* attributes. For an aimConstraint, the constraintTranslate, constraintRotatePivot, constraintRotateTranslate, constraintJointOrient, and constraintParentInverseMatrix are inputs to the aimConstraint. The attributes constraintRotate and constraintVector are outputs.

The additional aimConstraint inputs tell the constraint node how to orient the constrained object. The aimVector attribute defines a vector in the space of the constrained object that should be oriented along the line from the pivot point of the constrained object to the target point. The upVector, worldUpVector, worldUpMatrix, and worldUpType define how the constrained object is rotated about the aimVector.

The upVector defines a vector in the space of the constrained object, very much like the aimVector does. The constrained object is rotated so that the aimVector points at the target point and so that the upVector aligns as closely as possible with the computed world up vector. The world up vector is determined by the worldUpType, worldUpVector, and worldUpMatrix attributes.

The attribute worldUpType can have one of 5 values, which affects the calculation of the world up vector as shown in the following table.

Mnemonic	Value	Description
scene	0	The upVector is aligned with the up axis of the scene and worldUpVector and worldUpObject are ignored.
object	1	The upVector is aimed as closely as possible to the origin of the space of the worldUpObject and the worldUpVector is ignored.
objectrotation	2	The worldUpVector is interpreted as being in the coordinate space of the worldUpObject, transformed into world space and the upVector is aligned as closely as possible to the result.
vector	3	Default: The upVector is aligned with worldUpVector as closely as possible and worldUpMatrix is ignored.
none	4	No up vector is used in the computation of the orientation of the constrained object; only the aim vector and the target's position are used. Specifying an up vector can cause flipping to occur if the constrained object's new orientation vector is close to the up vector. If the worldUpType is instead set to none, this flipping won't happen, at a loss of control over twisting.

While setAttr requires the numeric values for the worldUpType attribute, both numeric and mnemonic values are allowed by the aimConstraint command.

Although the all the constraint nodes inherit from transform, they do not actively use any of the attributes from transform.

geometryConstraint, normalConstraint, orientConstraint, parentConstraint, pointConstraint, poleVectorConstraint, tangentConstraint, scaleConstraint, lookAt

The following quick index only shows top-level attributes (too many attributes to show them all): aimVector (3), constraintJointOrient (3), constraintParentInverseMatrix, constraintRotate (3), constraintRotateOrder, constraintRotatePivot (3), constraintRotateTranslate (3), constraintTranslate (3), constraintVector (3), inverseScale (3), offset (3), restRotate (3), scaleCompensate, target (14), upVector (3), useOldOffsetCalculation, worldUpMatrix, worldUpType, worldUpVector (3)

Long name (short name)	Type	Default	Flags
target (tg)	compound	n/a
Array of all information for all the targets
targetTranslate (tt) double3 Input translate of a target. targetTranslateX (ttx) distance (double) 0.0cm Input translateX of a target. targetTranslateY (tty) distance (double) 0.0cm Input translateY of a target. targetTranslateZ (ttz) distance (double) 0.0cm Input translateZ of a target.
targetRotatePivot (trp) double3 Input rotatePivot of a target. targetRotatePivotX (trpx) distance (double) 0.0cm Input rotatePivotX of a target. targetRotatePivotY (trpy) distance (double) 0.0cm Input rotatePivotY of a target. targetRotatePivotZ (trpz) distance (double) 0.0cm Input rotatePivotZ of a target.
targetRotateTranslate (trt) double3 Input rotatePivotTranslate of a target. targetRotateTranslateX (trtx) distance (double) 0.0cm Input rotatePivotTranslateX of a target. targetRotateTranslateY (trty) distance (double) 0.0cm Input rotatePivotTranslateY of a target. targetRotateTranslateZ (trtz) distance (double) 0.0cm Input rotatePivotTranslateZ of a target.
targetParentMatrix (tpm) matrix identity Input parentMatrix of a target.
targetWeight (tw) double 1.0 Input weight for a target.
constraintParentInverseMatrix (cpim)	matrix	identity
Input parentInverseMatrix for the constrained object.
aimVector (a)	double3	1.0,0.0,0.0
Input aimVector in constrained object coordinate system.
aimVectorX (ax) double 1.0 Input aimVectorX in constrained object coordinate system.
aimVectorY (ay) double 0.0 Input aimVectorY in constrained object coordinate system.
aimVectorZ (az) double 0.0 Input aimVectorZ in constrained object coordinate system.
upVector (u)	double3	0.0,1.0,0.0
Input upVector in constrained object coordinate system.
upVectorX (ux) double 0.0 Input upVectorX in constrained object coordinate system.
upVectorY (uy) double 1.0 Input upVectorY in constrained object coordinate system.
upVectorZ (uz) double 0.0 Input upVectorZ in constrained object coordinate system.
worldUpVector (wu)	double3	0.0,1.0,0.0
Input worldUpVector in world coordinates.
worldUpVectorX (wux) double 0.0 Input worldUpVectorX in world coordinates.
worldUpVectorY (wuy) double 1.0 Input worldUpVectorY in world coordinates.
worldUpVectorZ (wuz) double 0.0 Input worldUpVectorZ in world coordinates.
worldUpMatrix (wum)	matrix	identity
Input worldMatrix for the up object.
worldUpType (wut)	enum	3 vector
Input control value for computation of world up vector.
constraintTranslate (ct)	double3
Input constrained object translate value.
constraintTranslateX (ctx) distance (double) 0.0cm Input constrained object translateX value.
constraintTranslateY (cty) distance (double) 0.0cm Input constrained object translateY value.
constraintTranslateZ (ctz) distance (double) 0.0cm Input constrained object translateZ value.
constraintRotatePivot (crp)	double3
Input constrained object rotatelPivot value.
constraintRotatePivotX (crpx) distance (double) 0.0cm Input constrained object rotatelPivotX value.
constraintRotatePivotY (crpy) distance (double) 0.0cm Input constrained object rotatelPivotY value.
constraintRotatePivotZ (crpz) distance (double) 0.0cm Input constrained object rotatelPivotZ value.
constraintRotateTranslate (crt)	double3
Input constrained object rotatePivotTranslate value.
constraintRotateTranslateX (crtx) distance (double) 0.0cm Input constrained object rotatePivotTranslateX value.
constraintRotateTranslateY (crty) distance (double) 0.0cm Input constrained object rotatePivotTranslateY value.
constraintRotateTranslateZ (crtz) distance (double) 0.0cm Input constrained object rotatePivotTranslateZ value.
constraintRotateOrder (cro)	enum	0
Input constrained object rotate order value.
constraintJointOrient (cjo)	double3
Input constrained object joint orient (if any).
constraintJointOrientX (cjox) angle (double) 0.0deg Input constrained object joint orient X.
constraintJointOrientY (cjoy) angle (double) 0.0deg Input constrained object joint orient Y.
constraintJointOrientZ (cjoz) angle (double) 0.0deg Input constrained object joint orient Z.
scaleCompensate (ssc)	bool	true
Indicates whether to compensate for the scale of the parent joint.
inverseScale (is)	double3
Input constrained object scale of the parent joint.
inverseScaleX (isx) double 1.0 X component of aParentScale.
inverseScaleY (isy) double 1.0 Y component of aParentScale.
inverseScaleZ (isz) double 1.0 Z component of aParentScale.
constraintRotate (cr)	double3
Output constrained object rotate.
constraintRotateX (crx) angle (double) 0.0deg Output constrained object rotateX.
constraintRotateY (cry) angle (double) 0.0deg Output constrained object rotateY.
constraintRotateZ (crz) angle (double) 0.0deg Output constrained object rotateZ.
constraintVector (cv)	double3
Output vector from constrained object to target position
constraintVectorX (cvx) distance (double) 0.0cm Output X vector from constrained object to target position
constraintVectorY (cvy) distance (double) 0.0cm Output Y vector from constrained object to target position
constraintVectorZ (cvz) distance (double) 0.0cm Output Z vector from constrained object to target position
offset (o)	double3
object offset
offsetX (ox) angle (double) 0.0deg object X offset
offsetY (oy) angle (double) 0.0deg object Y offset
offsetZ (oz) angle (double) 0.0deg object Z offset
restRotate (rsrr)	double3
rest orientation
restRotateX (rrx) angle (double) 0.0deg rest X orientation
restRotateY (rry) angle (double) 0.0deg rest Y orientation
restRotateZ (rrz) angle (double) 0.0deg rest Z orientation
useOldOffsetCalculation (uooc)	bool	false
Turning this on switches the offset calculation from computing an offset rotation matrix, to simply adding the individual offset values to the x, y, and z rotation value computed by the constraint.