The Viewer tab allows you to see bounding boxes on native USD geometry. By default, bounding boxes are shown for Prims meeting the following criteria:

• The Prim is a ‘model’ with valid authored extentsHint attribute.

• No descendants are Viewer-visible (according to scene graph expansion / Viewer Visibility).

Additionally, bounding boxes are drawn for boundable prims if they are unloaded (and so are excluded from Hydra rendering). Bounding boxes for unloaded prims have a subtle red tint, distinguishing them from those for loaded prims.

Note:  Where extentsHint is authored for multiple purposes, Katana displays only those for geometry that would be rendered in a final render (namely 'default' and 'render'), since the visual representation is a proxy for final geometry.

Bounding Box Options

Display of bounding boxes may be customized (or disabled) by setting the following values for the `KATANA_VIEWER_PRIM_BBOX` environment variable, as detailed in the Environment Variables section of the Katana Developer Guide.

• 0: No bounding boxes are shown.

• 1: Default (as described above).

• 2: Bounds are drawn for unloaded prims (not loaded prims), even if descendants are Viewer-visible.

• 3: A combination of the two previous options (loaded Viewer-visible leaf prims, and all [visible] unloaded prims).

Viewing Bounding Boxes

Bounding boxes are enabled by default. To turn bounding boxes on and off you can use the Viewer dropdown.

In the Viewer, find View > Bounding Boxes. Toggle the checkbox to enable or disable them.

Bounding Boxes in the Attributes Tab

In the Attributes tab, you can see the USD prim’s bounding box data and use the extentsHint attribute to add bounding box data to higher up locations.

Note:  We expect for the case of Payloads, that the extentHint parameter is placed on the location where the payload state is set, in order to avoid "loading" it to obtain their bounding box information.