RenderMan Options and Attributes

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Custom options and attributes

The RenderMan standard allows implementations to define non-standard per-scene "Options" and per-object "Attributes" to control implementation-specific features. As an example, the Pixie render engine has a nonstandard "visibility" attribute that can be used to control raytracing-related features of geometry such as whether it casts a shadow or not.

K-3D provides special User Properties allowing you to take advantage of the options and attributes supported by your render engine.

Usage

  • You can add options to a RenderManEngine node only.
  • You can add attributes to any renderable node, including MeshInstance, and the Quadrics Plugins primitives.
  • Use the Node Properties Panel "Add User Property" button to add an option or attribute to a node.
  • In the Add User Property dialog, change "Property Type" to "RenderMan Option" or "RenderMan Attribute" as appropriate.
  • Use the "Value Type" dropdown to select the data type for the attribute or option.
  • Use the "Parameter List" and "Name" fields to specify the identifier for the attribute or option. Refer to your render engine documentation for valid values for these fields.
  • Use the "Add" button to create the new property, then change it to the desired value in the usual way.
  • Add an optional human-readable label and description for the property. These will be used by the Node Properties Panel when displaying the new option.
  • Note: to specify attributes for a mesh, use the MeshInstance node, not the mesh source or mesh modifiers.

Caveats

  • The user interface does not prevent you from adding attribute and option properties to nodes that will ignore them.
  • Not all RenderMan types have corresponding controls for editing in the Node Properties Panel - as an example, hpoint attributes cannot be edited through the panel.
  • Attributes and options do not support array types - an attribute of type int[2] cannot be created.
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