User guide

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For cameras and lights.
• geometry.arbitrary is used to hold arbitrary data to be sent to the renderer together with geometry, such as
primvars in RenderMan or user data in Arnold.
Common attributes at material nodes include:
• Material.
For declarations of shaders and their parameters.
Location type, such as camera, light or polygon mesh, is held by an attribute called type. Common values for type
include:
• group for general group locations in the hierarchy.
• camera for cameras.
• light for lights.
• polymesh for a polygon mesh.
• subdmesh for a sub-division surface.
• nurbspatch for a NURBS surface.
• material for a location holding a material made of monolithic shaders.
• network material for a location holding a material defined by network nodes.
• renderer procedural for a location to run a renderer specific procedural such as a RenderMan procedural.
• scenegraph generator for a location to run a Katana Scene Graph Generator procedural.
NOTE: Attributes are also used to store data about procedural operations that need to be run
downstream, such as AttributeScripts deferred to run later in the node graph, or the set-ups for Scene
Graph Generators and Attribute Modifiers. For example, if you create an AttributeScript and ask for it to
be run during MaterialResolve, all the necessary data about the script is held in an attribute group called
scenegraphLocationModifiers.
Generating Scene Graph Data
The principle end-user interface in Katana is the Node Graph. Here you can create networks of nodes to - among
other things - import assets, create materials and cameras, set edits and overrides, and create multiple render
outputs in a single project. Node parameters can be animated, set using expressions, and manipulated in the Curve
Editor and Dope Sheet. The Node Graph can have multiple outputs, and even separate, disconnected parts, with
potentially different parameter settings at any time on the timeline.
When you evaluate scene data, the nodes are used to create a description of all necessary filters. The resulting filter
tree has a single root, and represents the recipe of filters needed to create the scene graph data for the current
frame, at your chosen output node.
7 SCENE ATTRIBUTES AND HIERARCHY | GENERATING SCENE GRAPH DATA