pymel.core.modeling.pointOnCurve¶

pointOnCurve(*args, **kwargs)¶

This command returns information for a point on a NURBS curve. If no flag is specified, it assumes p/position by default.

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.
curvatureCenter / cc		bool
	Returns the (x,y,z) center of curvature of the specified point on the curve
curvatureRadius / cr		bool
	Returns the radius of curvature of the specified point on the curve
frozen / fzn		bool
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
normal / no		bool
	Returns the (x,y,z) normal of the specified point on the curve
normalizedNormal / nn		bool
	Returns the (x,y,z) normalized normal of the specified point on the curve
normalizedTangent / nt		bool
	Returns the (x,y,z) normalized tangent of the specified point on the curve
parameter / pr		float
	The parameter value on curve Default:0.0
position / p		bool
	Returns the (x,y,z) position of the specified point on the curve
tangent / t		bool
	Returns the (x,y,z) tangent of the specified point on the curve
turnOnPercentage / top		bool
	Whether the parameter is normalized (0,1) or not Default:false Flag can have multiple arguments, passed either as a tuple or a list.

Derived from mel command maya.cmds.pointOnCurve

Example:

import pymel.core as pm

pm.pointOnCurve( 'curve1', pr=0.5, p=True )
# Returns the (x,y,z) position of curve1 at parameter 0.5.

pm.pointOnCurve( 'curve1', pr=0.5 )
# Returns the (x,y,z) position of curve1 at parameter 0.5, since
# position is the default information.

pm.pointOnCurve( 'curve1', pr=0.5, nn=True )
# Returns the (x,y,z) normalized normal of curve1 at parameter 0.5.

pm.pointOnCurve( 'curve1', pr=0.5, cr=True )
# Returns the curvature radius of curve1 at parameter 0.5.

infoNode = pm.pointOnCurve('curve1', ch=True, pr=0.55)
pm.getAttr(infoNode + ".position")  # returns the position
pm.getAttr(infoNode + ".normal")    # returns the normal

# Returns a string which is the name of a new pointOnCurveInfo
# dependency node.  With this node connected to the curve,
# the output values of the pointOnCurveInfo node are always current
# even if, for example, the parameter is being animated.