BRL-CAD Python Bindings

A Python binding prototype for BRL-CAD using CFFI, exposing BRL-CAD's geometry database to Python via a clean, Pythonic API.

Built Python Geometry Bindings project under BRL-CAD by Rohit S.

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Architecture

User Python code
      ↓
brlcad/ (Pythonic API — Database, GeometryObject, BoundingBox)
      ↓
_brlcad.pyd (CFFI compiled C extension)
      ↓
brlcad_wrap.c (C wrapper over BRL-CAD librt / libwdb)
      ↓
BRL-CAD .g geometry database

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What It Does

• Opens a BRL-CAD .g geometry database from Python
• Lists and queries all objects via clean Python classes
• Returns typed objects (GeometryObject) with attributes
• Computes 3D bounding boxes with center and size helpers
• Writes geometry to .g via libwdb (BOT mesh support)
• Procedural geometry generation from Python (rhombicuboctahedron demo)

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Requirements

• BRL-CAD compiled from source (tested on Windows, Visual Studio 2022)
• Python 3.13+
• CFFI (pip install cffi)
• scipy (pip install scipy) — for rhombicuboctahedron demo only

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Build

cd D:\python-brlcad
python build_brlcad.py

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Usage

import brlcad

# Open database
db = brlcad.open("model.g")
print(db)
# → Database(path='model.g', objects=7)

# Query object
obj = db.get("prim_0.s")
print(obj)
# → GeometryObject(name='prim_0.s', type='solid')

# Attributes
print(obj.type)          # → "solid"
print(obj.exists)        # → True

# Bounding box
bbox = obj.bounding_box
print(bbox.min)          # → (-46.0, 13.0, -51.0)
print(bbox.max)          # → (-10.0, 49.0, -15.0)
print(bbox.center)       # → (-28.0, 31.0, -33.0)
print(bbox.size)         # → (36.0, 36.0, 36.0)

# Existence check
db.exists("nonexistent") # → False
db.get_type("random_csg.c") # → "combination"

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Procedural Geometry Demo

Python-generated rhombicuboctahedron rendered in MGED (24 vertices, 44 faces):

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Sample Output

Database(path='random_csg.g', objects=7)
📦 Total objects: 7

🔷 GeometryObject(name='prim_0.s', type='solid')
   type  : solid
   bbox  : BoundingBox(min=(-46.0, 13.0, -51.0), max=(-10.0, 49.0, -15.0))
   center: (-28.0, 31.0, -33.0)
   size  : (36.0, 36.0, 36.0)

🔷 GeometryObject(name='random_csg.c', type='combination')
   type  : combination
   bbox  : BoundingBox(min=(-39.0, -20.0, -16.0), max=(18.0, 15.0, 35.0))
   center: (-10.5, -2.5, 9.5)
   size  : (57.0, 35.0, 51.0)

❌ 'nonexistent' not found

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Procedural Geometry Demo

python rhombicuboctahedron.py

Generates a mathematically precise rhombicuboctahedron (24 vertices, 44 faces) as a BRL-CAD BOT primitive, written to rhombicuboctahedron.g and renderable in MGED.

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Files

File	Purpose
brlcad/	Pythonic API package (Database, GeometryObject, BoundingBox)
brlcad_wrap.c	C wrapper over BRL-CAD librt / libwdb
brlcad_wrap.h	Public C API header
build_brlcad.py	CFFI build script
examples/demo.py	Clean usage demo
rhombicuboctahedron.py	Procedural geometry generator demo
random_csg.c	C procedural generator (also in BRL-CAD PR #224)

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Rohit S — GSoC 2026 applicant