pymel.core.animation.tangentConstraint

tangentConstraint(*args, **kwargs)

Constrain an object’s orientation based on the tangent of the target curve[s] at the closest point[s] to the object. A tangentConstraint takes as input one or more NURBS curves (the targets) and a DAG transform node (the object). The tangentConstraint orients the constrained object such that the aimVector (in the object’s local coordinate system) aligns in world space to combined tangent vector. The upVector (again the the object’s local coordinate system) is aligned in world space with the worldUpVector. The combined tangent vector is a weighted average of the tangent vector for each target curve at the point closest to the constrained object.

Maya Bug Fix:

• when queried, angle offsets would be returned in radians, not current angle unit

Modifications:

• added new syntax for querying the weight of a target object, by passing the constraint first:

  aimConstraint( 'pCube1_aimConstraint1', q=1, weight ='pSphere1' )
  aimConstraint( 'pCube1_aimConstraint1', q=1, weight =['pSphere1', 'pCylinder1'] )
  aimConstraint( 'pCube1_aimConstraint1', q=1, weight =[] )
  

Flags:

Long name (short name)		Argument Types	Properties
aimVector (aim)		float, float, float
	Set the aim vector. This is the vector in local coordinates that points at the target. If not given at creation time, the default value of (1.0, 0.0, 0.0) is used.
layer (l)		unicode
	Specify the name of the animation layer where the constraint should be added.
name (n)		unicode
	Sets the name of the constraint node to the specified name. Default name is constrainedObjectName_constraintType
remove (rm)		bool
	removes the listed target(s) from the constraint.
targetList (tl)		bool
	Return the list of target objects.
upVector (u)		float, float, float
	Set local up vector. This is the vector in local coordinates that aligns with the world up vector. If not given at creation time, the default value of (0.0, 1.0, 0.0) is used.
weight (w)		float
	Sets the weight value for the specified target(s). If not given at creation time, the default value of 1.0 is used.
weightAliasList (wal)		bool
	Returns the names of the attributes that control the weight of the target objects. Aliases are returned in the same order as the targets are returned by the targetList flag
worldUpObject (wuo)		PyNode
	Set the DAG object use for worldUpType “object” and “objectrotation”. See worldUpType for greater detail. The default value is no up object, which is interpreted as world space.
worldUpType (wut)		unicode
	Set the type of the world up vector computation. The worldUpType can have one of 5 values: “scene”, “object”, “objectrotation”, “vector”, or “none”. If the value is “scene”, the upVector is aligned with the up axis of the scene and worldUpVector and worldUpObject are ignored. If the value is “object”, the upVector is aimed as closely as possible to the origin of the space of the worldUpObject and the worldUpVector is ignored. If the value is “objectrotation” then 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. If the value is “vector”, the upVector is aligned with worldUpVector as closely as possible and worldUpMatrix is ignored. Finally, if the value is “none” no twist calculation is performed by the constraint, with the resulting “upVector” orientation based previous orientation of the constrained object, and the “great circle” rotation needed to align the aim vector with its constraint. The default worldUpType is “vector”.Flag can appear in Create mode of commandFlag can have multiple arguments, passed either as a tuple or a list.
worldUpVector (wu)		float, float, float
	Set world up vector. This is the vector in world coordinates that up vector should align with. See -wut/worldUpType (below)for greater detail. If not given at creation time, the default value of (0.0, 1.0, 0.0) is used.

Derived from mel command maya.cmds.tangentConstraint

Example:

import pymel.core as pm

import maya.cmds as cmds

# orients the aim vector of cube1 in it's local coordinate space,
# to the tangent vector of curve1 at the closest point to  cube1.
pm.tangentConstraint( 'curve1', 'cube1' )

# uses the average of the tangents from curve1 and curve2.
pm.tangentConstraint( 'curve1', 'curve2', 'cube2', w=.1 )

# sets the weight for curve1's effect on cube2 to 10.
pm.tangentConstraint( 'curve1', 'cube2', e=True, w=10. )

# removes curve2 from cube2's tangentConstraint
pm.tangentConstraint( 'curve2', 'cube2', e=True, rm=True )

# adds curve3 to cube2's tangent constraint with the default weight
pm.tangentConstraint( 'curve3', 'cube2' )