OCT
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Radiance Octree.
At a glance
| Original creator | Greg Ward, Lawrence Berkeley National Laboratory (Radiance) |
| Purpose | A Radiance octree: the spatial index the oconv program builds over a scene so the renderers do not have to sort its geometry. |
| Extensions | .oct |
| Poka parser | poka-oct |
| Viewer | poka-metadata-card-viewer |
| Depth tier | Metadata card (see Depth tiers) |
| Breadth tier | B4 Summary (see Breadth tiers) |
How much Poka reads
B4 Summary. The container and metadata are read and summarised (counts, properties, structure), but the main content is not rendered.
Confidence: high (the reviewer read the code and a test that proves the claim). Basis: Reviewed 2026-10-16: poka-oct lib.rs (header split, NUL-terminated bounding cube, scene-file names, primitive-name scan, frozen/plain cross-check, unit tests) and tests/samples.rs over 5 corpus octrees (plain and frozen, from oconv). Metadata card only, no geometry view.
What Poka does not read
- Octree node structure is not decoded
- Frozen octrees: embedded geometry and materials are not decoded or drawn (only the presence of primitive type names)
- Light sources and sky data inside the octree are not read
- Plain octrees: referenced scene files are listed by name but not followed
Background
The file opens with Radiance's usual text header: the oconv command line that made it, FORMAT=Radiance_octree and a blank line. After it the file is binary, starting with the scene's bounding cube written as decimal strings. oconv writes two kinds of octree. A plain one records only the names of the scene files it was built from, which Radiance reads again at render time; a frozen one (oconv -f) embeds the geometry and stands alone. Poka shows which kind the file is, the command line, the bounding cube and, for a plain octree, the files it depends on.
Versions
| Version | Identifier | Poka | Note |
|---|---|---|---|
| Plain octree | FORMAT=Radiance_octree |
Partly read | The header, bounding cube and referenced scene file names are read; the octree node structure is not decoded. |
| Frozen octree (oconv -f) | FORMAT=Radiance_octree |
Partly read | Recognised, with its table of primitive types; the embedded geometry is not drawn. |