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Synopsis

curveIntersect [-caching boolean] [-constructionHistory boolean] [-direction linear linear linear] [-directionX linear] [-directionY linear] [-directionZ linear] [-nodeState int] [-tolerance linear] [-useDirection boolean] string string

curveIntersect is undoable, queryable, and editable.

You must specify two curves to intersect.

This command either returns the parameter values at which the given pair of curves intersect, or returns a dependency node that provides the intersection information. If you want to find the intersection of the curves in a specific direction you must use BOTH the "-useDirection" flag and the "direction" flag.

Return value

stringthe parameter values at which two curves intersect.

In query mode, return type is based on queried flag.

Flags

caching, constructionHistory, direction, directionX, directionY, directionZ, nodeState, tolerance, useDirection
Long name (short name) Argument types Properties
Common flags
-caching(-cch) boolean createqueryedit
Toggle caching for all attributes so that no recomputation is needed
-constructionHistory(-ch) boolean create
Turn the construction history on or off.
-direction(-d) linear linear linear queryedit
The direction that the input curves are projected in before intersecting. This vector is only used if "useDirection" flag is true.
-directionX(-dx) linear queryedit
The X component of the direction that the input curves are projected in before intersecting. This vector is only used if "useDirection" flag is true.
-directionY(-dy) linear queryedit
The Y component of the direction that the input curves are projected in before intersecting. This vector is only used if "useDirection" flag is true.
-directionZ(-dz) linear queryedit
The Z component of the direction that the input curves are projected in before intersecting. This vector is only used if "useDirection" flag is true.
-nodeState(-nds) int createqueryedit

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-Blocking will reset back to Blocking.

The Normal and Blocking cases apply to all nodes, while HasNoEffect is node specific; many nodes do not support this option. Plug-ins store state in the MPxNode::state attribute. Anyone can set it or check this attribute. Additional details about each of these 3 states follow.

State Description
Normal The normal node state. This is the default.
HasNoEffect

The HasNoEffect option (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.

It’s typical to implement support for the HasNoEffect state in the node’s 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.

Blocking

This is implemented in the depend node base class and applies to all nodes. Blocking is 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 Blocking the 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 won’t evaluate after that. Note that a blocked node will still respond to getAttr requests but a getAttr on a downstream node will not reevaluate the blocked node.

Setting the root transform of a hierarchy to Blocking won’t automatically influence child transforms in the hierarchy. To do this, you’d need to explicitly set all child nodes to the Blocking state.

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
-tolerance(-tol) linear queryedit
The tolerance that the intersection is calculated with. For example, given two curves end-to-end, the ends must be within tolerance for an intersection to be returned.
Default: 0.001
-useDirection(-ud) boolean queryedit
If true, use direction flag. The input curves are first projected in a specified direction and then intersected. If false, this command will only find true 3D intersections.
Default: false
Flag can appear in Create mode of command Flag can appear in Edit mode of command
Flag can appear in Query mode of command Flag can be used more than once in a command.

MEL examples

curveIntersect curve1 curve2;
// Returns the parameter values that the curves intersect at.
// eg. if 6 parameter values are returned, the first 3 are
// on curve1 and the last 3 are on curve2.

curveIntersect -useDirection true -direction 0 1 0 curve1 curve2;
// Returns the parameter values that the curves intersect at
// when projected along vector (0, 1, 0).  This is useful
// for example when you are viewing the two curves in an orthographic
// view and the curves appear to intersect, even though
// they do not intersect in 3D.

string $node = `curveIntersect -ch on curve1 curve2`;
float $p1[] = `getAttr ($node + ".parameter1")`;    // or use ".p1"
float $p2[] = `getAttr ($node + ".parameter2")`;    // or use ".p2"
// Returns a string which is the name of a new curveIntersect
// dependency node.
// The "getAttr" commands return the parameter values at
// which the curves intersect each other.