sysml

Read SysML v2 and KerML models from Python. Every metaclass of the specification is a Python class, and every property and operation keeps its specification name (ownedFeature, qualifiedName, effectiveName()). A model is read through one of two backends, with the same classes over both:

• the OpenMBEE SysML Toolkit reads your .sysml and .kerml files, resolves names and computes derived properties;
• a payload is a model exported as full-form interchange JSON by any SysML v2 tool.

pip install sysml

Python 3.10 or newer. The wheels for Windows x64, Linux x64 (glibc 2.28 or later), and macOS on Apple silicon (11 or later) and on Intel (10.12 or later) carry the SysML Toolkit's binding library and the standard library models. On other platforms pip installs the source distribution, which reads payloads only.

First: the standard library

Most models refer to the KerML and SysML standard library (ScalarValues::Real, ISQ::mass, and implicitly Parts::parts and the like). Get it once, at the start of your program:

from sysml import standard_library, standard_library_json

library_dir = standard_library()          # the library models the wheel carries, for the SysML Toolkit
library_json = standard_library_json()    # the library as JSON, for payloads

standard_library_json() downloads the JSON (about 11 MB) from this version's GitHub release on its first call, checks it against the SHA-256 GitHub states for the file, and keeps it in your user cache; later calls read the cache. Where GitHub cannot be reached, download sysml_library-<version>.zip from the release yourself and set SYSML_LIBRARY_JSON to the sysml.library.full.json it holds.

Read a model through the SysML Toolkit

from sysml import Model, standard_library

model = Model.from_toolkit("model.sysml", library_dir=standard_library())
vehicle = model.resolve("Vehicles::Vehicle")
print(vehicle.qualifiedName, [f.declaredName for f in vehicle.ownedFeature])

Read a payload

import json
from sysml import Model, PayloadLibrary, standard_library_json

with open(standard_library_json(), encoding="utf-8") as f:
    library = PayloadLibrary(json.load(f))      # read once, share it
with open("model.json", encoding="utf-8") as f:
    model = Model.from_full_json(json.load(f), library=library)

More

• The Python guide: https://github.com/Open-MBEE/sysml-sdk/blob/main/examples/python/README.md
• The SDK, its other languages (JavaScript/TypeScript, Java, C#, C++) and its documentation: https://github.com/Open-MBEE/sysml-sdk
• What is new, and what the SysML Toolkit does not answer yet: https://github.com/Open-MBEE/sysml-sdk/blob/main/CHANGELOG.md

The SDK is licensed under the Apache License 2.0. The standard library models the wheels carry, and the library JSON, are licensed under the Eclipse Public License 2.0: see sysml/stdlib/LICENSE and sysml/stdlib/NOTICE in the installed package.