These nodes can be used to retrieve attributes from the attached geometry. When the scene is translated to Arnold, attributes are not exported automatically. They must be declared, according to the Arnold scene syntax, in the User Options field of the Arnold Parameters (see below for some examples). On export, MAXtoA translates them into user attributes on the Arnold geometry. To retrieve this data, a node is then required of the correct type. While there are more types than listed below, these should cover the type dimensions, (int, string, 1,3, and 4 floats). In Arnold, the parameter is selected by name only. The nodes below are very accepting of inputs. If for example, an attribute is named in user_data_rgb but the input passed is actually an integer, then it will still work and just convert the integer to float and pass it to each of the R, G & B values.
It is also possible to read user data fields from volumetric shapes, allowing things like per-particle user data on volumetric spherical point clouds to affect the result of volumetric shading.
User Data Float
Attribute
Read float value from shape user data, at the current shading point on the surface.
Default
Output value to use if user data with the specified name is not available.
User Data Int
Attribute
Read integer value from shape user data, at the current shading point on the surface.
Default
Output value to use if user data with the specified name is not available.
User Data RGB
Attribute
Read RGB color from shape user data, at the current shading point on the surface.
Default
Output value to use if user data with the specified name is not available.
User Data RGBA
Attribute
Read RGB color and alpha from shape user data, at the current shading point on the surface.
Default
Output value to use if user data with the specified name is not available.
User Data String
Attribute
Reads the string from shape user data.
Default
Output value to use if user data with the specified name is not available.