Encapsulates 3D parameterization for pattern generators. Allows selection of Pref and specification of a coordinate system to transform to. Uses a simple struct to represent bundled dataflow of outputs. @parameters

scale: Scale the frequency of the feature uniformly in 3D

use: Select the type of position you want to use. You can only use __Pref and __WPref if these primitive variables have been attached to your geometry.

pref: Name of geometry Pref (Maya uses __Pref and __WPref). If empty, we will use __Pref or __WPref, depending on the value of 'use'. If all fails, we will use P.

coordsys: Name of coordinate system transform (e.g. place3dtexture node in Maya). Standard coordinate systems : 'object', 'world', 'screen', 'NDC'. If empty, we assume 'object' space, which is fine for non-deforming geometry.

VOP nodes