cad2d-ir 0.1.0

Intermediate representation (IR) for 2D CAD and DXF converters

cad2d-ir

cad2d-ir is an intermediate representation (IR) for 2D CAD data, plus converters between DXF and that IR.

The goal is to provide a stable, machine-friendly format for:

• CAD ingestion pipelines
• geometric post-processing
• round-trip conversion workflows

Status

The project currently supports:

• LINE, CIRCLE, ARC, LWPOLYLINE, TEXT
• MTEXT, INSERT, HATCH
• staged support for SPLINE, DIMENSION, and constraints

See ir_schema.json for the canonical schema.

Installation

With pip

pip install cad2d-ir

For development (uv)

uv sync
uv run pytest

CLI

# Validate IR JSON
cad2d-ir validate examples/ir/minimal.json

# DXF -> IR
cad2d-ir dxf2ir examples/dxf/simple_line.dxf -o /tmp/out.json --pretty

# IR -> DXF
cad2d-ir ir2dxf examples/ir/minimal.json -o /tmp/out.dxf

Warnings (for example when constraints cannot be represented in plain DXF) are printed to stderr.

Python API

from cad2d_ir import convert_dxf_text_to_ir, convert_ir_to_dxf_text

dxf_text = "0\nSECTION\n2\nENTITIES\n0\nLINE\n10\n0\n20\n0\n11\n1\n21\n1\n0\nENDSEC\n0\nEOF\n"
to_ir = convert_dxf_text_to_ir(dxf_text)
print(to_ir.document["entities"][0]["kind"])  # LINE

to_dxf = convert_ir_to_dxf_text(to_ir.document)
print(len(to_dxf.warnings))

Lower-level conversion functions (dxf_to_ir, ir_to_dxf) are also available.

Repository layout

src/cad2d_ir/
  api.py             # public high-level API
  cli.py             # CLI entrypoint
  schema.py          # schema loading + validation
  codecs/dxf.py      # DXF <-> IR conversion
  data/ir_schema.json
ir_schema.json       # canonical schema source
tests/
examples/
docs/

Compatibility and limitations

• constraints are preserved in IR but omitted when exporting to DXF.
• DIMENSION support is semantic/staged and may not preserve every CAD-system-specific detail.
• HATCH currently focuses on polyline-style loops.

Development

uv run pytest -q
uv run cad2d-ir --help

See:

• CONTRIBUTING.md
• docs/API.md
• docs/SCHEMA_NOTES.md

License

MIT (LICENSE)