Module orc 

OpenRocket’s .orc parts catalogs: nose cones, tubes, rings, transitions, parachutes and streamers as their makers sell them, by maker and part number.

A .orc file is XML: an <OpenRocketComponent> root holding a <Version>, a <Materials> list (each a name, a density, the density’s units and its kind: BULK, SURFACE or LINE) and a <Components> list of parts. A part names its maker, part number and description, its dimensions each with its own Unit attribute, and its material by name and kind; the material must be defined in the same file. The format has no published schema; its field list and units are the ones the openrocket-database project documents (docs/TechnicalInfo.md at the pinned commit), and what each field means is what OpenRocket 24.12’s preset loader makes of it, measured by running that loader on the same files as an oracle (validation/oracles/openrocket/orc_presets.py).

read reads one file into a Catalog. bundled is the catalog OpenRocket 24.12 ships: the 16 files of openrocket-database (Apache-2.0) at the commit validation/refs.lock.toml pins, compiled into this crate unchanged, 3,449 parts. Catalog::find looks a part up by maker and part number.

What is read, and how far it agrees with OpenRocket. Every value is converted to SI as the file states it: lengths in meters, masses in kilograms, densities in kg/m³, kg/m² or kg/m. On the bundled files, every part OpenRocket reads is read here, in the same order, and every value equals OpenRocket’s bit for bit (17,911 of 18,306 numbers), with four exceptions that the test crates/hpr-io/tests/orc_openrocket.rs counts:

• Ounces. OpenRocket’s ounce is 0.0283495231 kg; the avoirdupois ounce is exactly 0.028349523125 kg (NIST Handbook 44, Appendix C), and that is the one used here. The difference is 9e-10 of the value, on the 185 masses stated in ounces. OpenRocket rounds a few other imperial factors the same way (lb/ft³, oz/in², oz/ft², lb/ft², oz/ft); no bundled file uses them.
• Makers’ names. OpenRocket shows two makers under names of its own: “LOC Precision” as “LOC/Precision” and “Public Missiles” as “Public Missiles, Ltd.” The name here is the file’s.
• A stated mass. When a solid part states its mass, OpenRocket replaces its material’s density with the one that gives the part that mass. Here the material keeps the file’s density and the part keeps its mass (Part::mass_kg), which a design built from the part by hand can set as its mass. This is 207 parts; with the masses taken out of the files, OpenRocket’s density is the one read here on every one of them. A parachute’s or streamer’s stated mass leaves its fabric’s density alone, here and in OpenRocket.
• Undefined materials. A material the file names but doesn’t define has no density here (MaterialRef::density is None); OpenRocket gives it zero. This is 3 parts.

What the file leaves unsaid. No .orc field gives a nose or transition shape’s parameter (an ogive’s radius, a Haack series’ C), a shoulder’s wall, or a parachute’s drag coefficient; OpenRocket uses its own defaults for these when a part is put in a design. A part’s material is only as good as the file’s density, and the database’s own README warns to weigh real parts.

Warnings. A part or material that can’t be read is left out with a Warning saying why, rather than failing the file; so are fields ignored or repeated, and values read as written but implausible (an inside diameter not less than the outside, a solid lighter than air, a fabric under 1 g/m²). The bundled files give 55.

Structs

Bulkhead

A bulkhead: a solid disc.

Catalog

Parts, from one catalog file or several.

CatalogFile

A catalog file read, with what was left out of it.

CatalogMaterial

A material a catalog file defines.

MaterialRef

The material a part names, with the density its file defines for it.

NoseCone

A nose cone.

Parachute

A parachute.

Part

One part as its catalog lists it.

Streamer

A streamer.

Transition

A transition.

Tube

A tube-like part: a body tube, coupler, engine block, centering ring or launch lug.

Warning

Something read differently from what the file says, or left out. Reading goes on.

Enums

MaterialKind

The kind of density a material has.

OrcError

A .orc file that can’t be read at all.

PartKind

A part’s kind and dimensions.

Shape

A nose cone’s or transition’s profile, as the file names it.

WarningKind

What a Warning is about.

Constants

BUNDLED_FILES

The openrocket-database project’s catalog files (Apache-2.0; the license is data/openrocket-database/LICENSE beside them), unchanged, at the commit validation/refs.lock.toml pins (1512874a, 2025-07-27), which OpenRocket 24.12 ships byte for byte: each name with its text, in byte order of the names. generic_materials.orc defines materials and no parts.

MAX_DEPTH

The deepest nesting read. A .orc nests four deep (the root, the parts list, a part, its field); the parser below has been seen to exhaust a 2 MiB stack at 130 levels (the .ork reader’s measurement, crate::ork::MAX_DEPTH).

MAX_WARNINGS

The most warnings one file gives; past it, one last warning says how many more there were.

Functions

bundled

Every part of BUNDLED_FILES, file by file in their order: 3,449 parts. Read once, on the first call. The files’ 55 warnings are dropped here; read each of BUNDLED_FILES to see them.

read

Reads one .orc file’s text; file names it in each Part::file.