User guide

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Attribute data for a "geometry" group attribute may consist of child group attributes like "point", "poly", "vertex", and
"arbitrary", which can contain vertex normals and texture coordinates, for example. The actual attributes to include
for a "geometry" attribute depend on the type of location. For more information, please see the Katana Reference
Guide.
Providing Error Feedback
A scene graph generator plug-in can provide error feedback to the user if an error occurs while initializing the plug-in
or while generating scene graph locations and/or attributes.
Two scene graph attributes are used for providing error feedback:
• A location's type can be set to error to indicate a fatal error. The render output modules abort a render when
they encounter a location of type error . No further traversal occurs at that point.
• A location can have an errorMessage attribute added to it, which is interpreted as the description of an error that
occurred in the location. The given message is displayed underneath the location in the Scene Graph tab, and the
ScenegraphGeneratorResolve node that executed the SGG plug-in is displayed with a red halo in the Node Graph
tab (see images below).
If only an error message is provided without setting the location's type to error, the render output modules treat
the error as non-fatal and continue with traversing the scene graph for rendering.
8 SCENE GRAPH GENERATOR PLUG-INS | SGG PLUG-IN API CLASSES