LibraryFEMTherm

C++20 static library for reading, writing, and manipulating THERM (.thmz) files. Provides data structures and serialization for thermal models, materials, boundary conditions, gases, glazing systems, and CMA data. Optional Python bindings via pybind11.

Requirements

• CMake 3.8+
• C++20 compiler (MSVC 2022, GCC 11+, Clang 14+)
• Ninja or Visual Studio generator
• Python 3.11+ (only when building Python bindings)

Building

C++ only (default)

cmake --preset default
cmake --build build/default --config Release

C++ with Python bindings

cmake --preset python
cmake --build build/python --config Release

Manual configuration (Visual Studio generator)

cmake -G "Visual Studio 17 2022" -A x64 -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --config Release

Add -DBUILD_PYTHON_BINDINGS=ON to include Python bindings.

CMake presets

Preset	Description	Python bindings	C++ tests
default	C++ only	OFF	ON
python	C++ with Python bindings	ON	ON

CLion and VS Code automatically detect these presets.

Running tests

ctest --test-dir build/python -C Release -V

This runs both C++ Google Tests and Python pytest tests (when built with the python preset).

CMake options

Option	Default	Description
BUILD_PYTHON_BINDINGS	OFF	Build Python bindings via pybind11
BUILD_LibraryFEMTHERM_TESTING	ON	Build C++ test targets

Python bindings

Install from PyPI:

pip install libraryfemtherm

Or build from source with BUILD_PYTHON_BINDINGS=ON (see above).

import pylibraryfemtherm as fem

# Load a THMZ file
model = fem.load_model_from_zip_file("sample-sill.thmz")
print(f"Polygons:   {len(model.polygons)}")
print(f"Boundaries: {len(model.boundary_conditions)}")

# Save to XML string
xml = fem.save_model_to_string(model)

# Save to a new THMZ file
fem.save_model_to_zip_file(model, "output.thmz")

# Work with ZIP contents directly
contents = fem.zip.unzip_files("sample.thmz", [fem.zip.MATERIALS_FILE_NAME])
db = fem.MaterialsDB()
db.load_from_string(contents[fem.zip.MATERIALS_FILE_NAME])

For comprehensive Python API documentation with examples, see doc/python.md.

Project structure

src/
  BCSteadyState/     # Steady-state boundary conditions
  BCTransient/       # Transient boundary conditions
  CMA/               # CMA (Component Modeling Approach) data
  Common/            # Shared utilities
  Gases/             # Gas properties and mixtures
  Materials/         # Material definitions (solid, cavity, radiation)
  THMZ/              # ThermModel, geometry, preferences, properties, zip I/O
  LibraryUtilities/  # Common helpers
  Schemas/           # XML/JSON schemas
python/
  src/               # pybind11 binding source files
  tests/             # pytest test suite
tst/
  units/             # C++ Google Test files
  products/          # Test THMZ data files
cmake/               # CMake macros and compiler config

Dependencies (fetched automatically)

• FileParse - XML/JSON serialization
• LBNLCPPCommon - Common utilities
• miniz - ZIP compression
• pybind11 v2.13.6 - Python bindings (optional)
• Google Test v1.13.0 - Testing (optional)