pymel.core.modeling.pointCurveConstraint¶

pointCurveConstraint(*args, **kwargs)¶

The command enables direct manipulation of a NURBS curve. It does so by apply a position constraint at the specified parameter location on the NURBS curve. If construction history for the cmd is enabled, a locator is created to enable subsequent interactive manipulation of the curve. The locator position may be key framed or transformed and the curve1will try to match the position of the locator. The argument is a curve location

Flags:

Long Name / Short Name		Argument Types	Properties
caching / cch		bool
	Toggle caching for all attributes so that no recomputation is needed
constructionHistory / ch		bool
	Turn the construction history on or off.
frozen / fzn		bool
name / n		unicode
	Sets the name of the newly-created node. If it contains namespace path, the new node will be created under the specified namespace; if the namespace does not exist, it will be created.
nodeState / nds		int
	Maya dependency nodes have 6 possible states. The Normal (0), HasNoEffect (1), and Blocking (2)states can be used to alter how the graph is evaluated. The Waiting-Normal (3), Waiting-HasNoEffect (4), Waiting-Blocking (5)are for internal use only. They temporarily shut off parts of the graph during interaction (e.g., manipulation). The understanding is that once the operation is done, the state will be reset appropriately, e.g. Waiting-Blockingwill reset back to Blocking. The Normaland Blockingcases apply to all nodes, while HasNoEffectis node specific; many nodes do not support this option. Plug-ins store state in the MPxNode::stateattribute. Anyone can set it or check this attribute. Additional details about each of these 3 states follow. StateDescriptionNormalThe normal node state. This is the default.HasNoEffectThe HasNoEffectoption (a.k.a. pass-through), is used in cases where there is an operation on an input producing an output of the same data type. Nearly all deformers support this state, as do a few other nodes. As stated earlier, it is not supported by all nodes. Its typical to implement support for the HasNoEffectstate in the nodes compute method and to perform appropriate operations. Plug-ins can also support HasNoEffect. The usual implementation of this state is to copy the input directly to the matching output without applying the algorithm in the node. For deformers, applying this state leaves the input geometry undeformed on the output. BlockingThis is implemented in the depend node base class and applies to all nodes. Blockingis applied during the evaluation phase to connections. An evaluation request to a blocked connection will return as failures, causing the destination plug to retain its current value. Dirty propagation is indirectly affected by this state since blocked connections are never cleaned. When a node is set to Blockingthe behavior is supposed to be the same as if all outgoing connections were broken. As long as nobody requests evaluation of the blocked node directly it wont evaluate after that. Note that a blocked node will still respond to getAttrrequests but a getAttron a downstream node will not reevaluate the blocked node. Setting the root transform of a hierarchy to Blockingwont automatically influence child transforms in the hierarchy. To do this, youd need to explicitly set all child nodes to the Blockingstate. For example, to set all child transforms to Blocking, you could use the following script. import maya.cmds as cmds def blockTree(root): nodesToBlock = [] for node in {child:1 for child in cmds.listRelatives( root, path=True, allDescendents=True )}.keys(): nodesToBlock += cmds.listConnections(node, source=True, destination=True ) for node in {source:1 for source in nodesToBlock}.keys(): cmds.setAttr( ‘%s.nodeState’ % node, 2 ) Applying this script would continue to draw objects but things would not be animated. Default:kdnNormal
object / o		bool
	Create the result, or just the dependency node.
pointConstraintUVW / puv		float, float, float
	Point constraint parameter space location on input NURBS Object
pointWeight / pw		float
	Point constraint weight. Determines how strong an influence the constraint has on the input NURBS object. Default:1.0
position / p		float, float, float
	The new desired position in space for the nurbs object at the specified parameter space component. If not specified, the position is taken to be the one evaluated at the parameter space component on the nurbs object.
replaceOriginal / rpo		bool
	Create in place(i.e., replace). Flag can have multiple arguments, passed either as a tuple or a list.
weight / w		float
	weight of the lsq constraint. The larger the weight, the least squares constraint is strictly met. Common flags

Derived from mel command maya.cmds.pointCurveConstraint

Example:

import pymel.core as pm

# Apply a constraint to manipulate the  position corresponding to
# the 1st edit point on curve1.
pm.pointCurveConstraint( 'curve1.ep[1]', ch=True )

# Apply a constraint to manipulate the end point on curve1.
pm.pointCurveConstraint( 'curve1.un[1.0]', ch=True, w=1.0 )

# Apply a constraint around the midpoint in the parameter domain on curve1.
pm.pointCurveConstraint( 'curve1.un[0.5]', ch=True, w=-1.0 )