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This page contains information about the V-Ray Pattern ID node.


The V-Ray Pattern ID VOP is intended to be used with the V-Ray Multi ID Material and/or the V-Ray Multi ID Texture. This V-Ray for Houdini-specific node was developed to simplify material assignments to Alembic Delayed Load Primitives. This is achieved by providing you with access to the primitive string attributes stored inside the Delayed-Load alembic file.

Access to the s@name attribute inside the Alembic file does not require unpacking it. Because of this, the generated VRScenes are kept as light as possible - the alembic geometry is loaded on-demand and the material assignments happen at render-time.

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Attribute – The primitive string attribute to sample.

Use Scene Name – When enabled, the "scene_name" parameter in the VRScene is used for pattern generation. The "scene_name" is based on the Geometry node name in the case of live mesh geometry, on the packed primitive "name" attribute for packed primitives, and on the "path" attribute in the case of Delayed-Load alembic files.

Num. Patterns – Specifies the number of unique ID values to generate. You can use regex-style notation in the pattern names – please refer to the example scene in the Overview section.

Pattern – Specifies the string to match. The following regex-style notation is supported:

  • * - matches any number of any characters including none ("Law*" matches "Law", "Laws", or "Lawyer")
  • ? - matches any single character ("?at" matches "Cat", "cat", "Bat" or "bat")
  • [abc] - matches one character given in the bracket ("[CB]at" matches "Cat" or "Bat")
  • [a-z] - matches one character from the range given in the bracket ("Letter[0-9]" matches "Letter0", "Letter2")

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