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This node runs the expression on every point/primitive/vertex
(depending on the Class parameter) in the input geometry.
Each expression will be assigned to the specified group. To get the group’s
current value, use the
It can access information from other geometry using attributes and VEX functions.
Unlike Wrangle nodes, you do not have to write a complete VEX statement, only a VEX expression. Each expression is wrapped with an assignment to the given group and a semicolon. If you need to write a more complicated multi-line function, use the Attribute Wrangle with
The generated VEX snippet can be viewed by updating the generated code tab.
Press on the node to see any error output from the snippet.
You can use the VEX function
chto evaluate parameters. The path is relative to this node (
ch("parm")will evaluate the parameter
parmon this node). This evaluation will be done at the current time.
Unlike the Attrib Create SOP, this does not use local variables. Further, all backtick expressions and
$Fvariables will be evaluated at frame 1, not the current time. Use
What type of groups to edit. All group expressions are run in a single pass so must have the same group type.
Number of vexpressions to apply.
Name of group to generate.
A single expression in VEX, with no assignment or semi-colon.
How to merge the expression with any existing group of the same name.
Evaluation Node Path
VEX functions like
ch() usually evaluate with respect to this node.
Enter a node path here to override where the path search starts from.
This is useful for embedding in a digital asset, where you want searches
to start from the asset root.
Attribute To Match
Which attribute to use for matching. This attribute must be
present on both inputs for matching to be done. Otherwise matching
is done by element number (e.g., point number when running over points).
The attribute should either be an integer or string attribute.
This controls how the
opinput#_ virtual bindings connect.
You can use
v@opinput1_Cd, for example, to read the second input’s
Updates the generated code parameter with the the current state of the set of snippets.
The equivalent code for an Attribute Wrangle SOP to perform the functions of the expressions. This is useful if a simple expression becomes complicated and you want to upgrade it to a full wrangle SOP. Changing this does not affect the behavior of the node.
The following examples include this node.
This example demonstrates dynamically stitching or gluing Vellum geometry together during a simulation.