Draw the model. Click run. Read the diagrams.

Pre-alpha. Under active development. APIs and file formats will change.

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SAP2000-style menus	Compact dark toolbar	Parametric grid wizard

What is OTKO?

OpenSees does nonlinear FEM well. Its user interface is a script. OTKO puts a visual front-end on top of it: draw nodes, frames, supports, and loads on a snapped grid; assign materials, sections, and load patterns through dialogs; run the analysis with progress and cancel; then read the results — deformed shapes, mode shapes, force diagrams, pushover curves, hysteresis loops.

Underneath, the core Pydantic model works fine from a script or notebook without any GUI. The GUI is a front-end, not the whole product.

Highlights

Area	What you get
Modeling	Grid wizards, nodes, frames (elastic + force-based), trusses, quads, zero-length sections, restraints, equalDOF constraints, distributed loads, ground motions (PathTimeSeries / UniformExcitation).
Materials & sections	Steel01, Steel02, Concrete01, Concrete02, ElasticPP, Hysteretic, fiber sections (rectangular / circular patches + rebar), SectionAggregator, BeamWithHinges.
Analysis	Static (load- or displacement-controlled), modal, pushover, transient time-history with mode-1 Rayleigh damping. Chained workflows: gravity preload → loadConst -time 0.0 → pushover or transient.
Post-processing	Deformed shape with scale slider, animated mode shapes, axial / shear / moment diagrams, pushover curves, time-history plots, hysteresis loops, response-spectrum SRSS / CQC, snapshot + video export.
Persistence	One Pydantic-validated .osmodel JSON per project — diffs cleanly in Git, builds cleanly from Python. Analysis output in HDF5 (*.osresults.h5).

20+ verified examples ship with the repo, including OpenSees Wiki Examples 1–4 and a fiber-section RC frame pushover. See examples/README.md.

Quick start

git clone ssh://git@smill-home.ddns.net/smill/otko.git
cd otko

python -m venv .venv
.venv\Scripts\activate              # Windows
source .venv/bin/activate           # Linux / macOS

pip install -e ".[gui,dev]"         # desktop: Qt + PyVista + dev tools
# pip install -e .                  # headless: core + services only

python -m otko

Then:

1. File → Open → examples/cantilever.osmodel.
2. Analyze → Cases → run Tip-Load.
3. Display → Show Force Diagram → M3: 50 kN·m at the fixed end. V2: constant −10 kN.
4. Display → Show Deformed Shape → the cantilever curve.

Nonlinear version: open examples/portal_pushover.osmodel, run Push-X, Display → Show Pushover Curve — elastic ramp, then a yield plateau as the base hinges form.

Python 3.10+. On Windows use 3.12+ — openseespywin==3.8.0.0 has no 3.11 wheel (Requires-Python >=3.12). Both pins already live in pyproject.toml.

Architecture

Strict MVVM + service layer, one direction only:

views (Qt)  →  viewmodels  →  services (OpenSeesRunner, Persistence)  →  core (model)

core is pure Python — no Qt, no OpenSeesPy imports — and unit-tests in isolation. PySide6 + PyVista on the view, pyqtgraph for 2D plots, Pydantic v2 for the model, h5py for results. Long version, including the OpenSeesPy command order the runner emits, in docs/architecture.md.

Roadmap

docs/roadmap.md has the phase-by-phase plan. Phases 0–7 (modeling, analysis, post-processing) are mostly done. Phase 8 — isolators, ground-motion library, IDA, fiber-section editor polish — is where the open work is.

Contributing

Collaborators welcome — most useful to people who already work with OpenSees and want a shorter path from idea to model:

• Structural / earthquake engineers who can tell us when a feature is almost right but not quite.
• Researchers running pushover, IDA, or response-spectrum studies against hand-built scripts.
• Python / Qt developers into scientific desktop apps, VTK rendering, or Pydantic schema design.
• Students learning FEM and GUI architecture — the examples and tests are meant to read as documentation.
• UX / icon designers willing to argue about dialogs and toolbars.

Bug reports and reproducible test cases count as contributions. Setup and the rules enforced in review: CONTRIBUTING.md.

Test suite:

pytest tests/unit          # pure logic, milliseconds
pytest tests/gui           # Qt event-loop tests (pytest-qt)
pytest tests/integration   # real OpenSeesPy runs on bundled examples

CI runs lint + the non-slow subset on Linux / macOS / Windows × Python 3.10 / 3.11 / 3.12.

License

OTKO is GNU Affero General Public License v3.0 (LICENSE). In short:

• Research, education, personal projects: fine, keep the copyright notice.
• Fork and modify: fine.
• Distribute it (modified or not): release your full source under AGPL-3.0.
• Run a modified version as a network service: release your modifications under AGPL-3.0.

Commercial forks stay open. If you need a different arrangement (e.g. a closed-source commercial license), open an issue.

Copyright © 2026 Ozan and contributors.