ModOnda
Open the workbench

Free public beta · Modelica Standard Library 4.1 · in your browser

Model and simulate physical systems in your browser.

ModOnda compiles Modelica models to native code and WebAssembly, simulates them with its own solvers, and plots the results beside the diagram. Nothing to install, and the workbench is free to use.

Open the workbench Read the docs

Signing in is optional. The workbench runs without an account.

The ModOnda workbench with a hydraulic aileron actuator model in the diagram view, its package tree on the left and the component panel on the right.
Diagram view of the AileronActuator example from the Modelica Standard Library.
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MSL 4.1.0 example models run to the end
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match the MSL reference results
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reference exceptions, each documented with its reason
Free
public beta, nothing to install

01

Built for models that are too big to wait on

A Rust core runs the same compiler and solvers on a server and in a browser tab.

Symbolic backend

Alias elimination, Pantelides index reduction with dummy derivatives, BLT sorting and tearing, and exact symbolic Jacobians, evaluated by a compiled register tape.

Solvers you can choose

Variable-order BDF, Radau IIA and ESDIRK with colored Jacobians and dense or sparse LU. Dopri5 switches to BDF when a model turns stiff. RK4 and Euler are there for fixed steps.

Events and discrete logic

Zero-crossing events, when, elsewhen and reinit, and state machines drawn as diagrams.

Workbench in the Dymola style

Package browser, icon, diagram and text views of every class, a variable browser, a plot window with display units, and simulation setup in one place.

Standard Library ready

Modelica Standard Library 4.1.0 loads in the browser, including MultiBody, the QuasiStatic machines, Media (IF97 water, R134a, moist air) and Fluid. 3-D animation replays MultiBody models.

Results and scripting

Results go to Dymola-format .mat files or CSV, readable by Dymola, OMEdit and DyMat.

02

Inside the workbench

Every view below is a live part of the app, not a mock-up.

A plot window with simulated curves for several variables of a model.
Plot. Tick a variable to draw it, with display units and subplots.
The Modelica text view of a class, with syntax colouring.
Text. Edit Modelica source with go to definition, rename and completion.
A 3-D animation of an aileron actuator model replayed after a simulation.
Animation. Replay a MultiBody model in 3-D after a run.

03

Checked against the reference results

Each Standard Library example is compared with its reference result. The scoreboard lists every example, the signals that differ, and the reference exceptions with the reason each one is documented.

04

Pricing

The beta is free, and it takes no payment. The paid parts are not live yet, so they are marked as coming soon.

Available now

Beta

$0

  • The workbench, in the browser
  • Documentation, examples and the scoreboard
  • Assistant with your own OpenRouter key
Open the workbench

Coming soon

Hosted assistant

$0 for 10 messages a month

  • 10 free assistant messages for each user, every month
  • No key of your own needed

Coming soon

Message packs

10¢ a message, in packs

  • 50 messages for $5, 100 for $10, 500 for $50
  • Buy more when the free ones run out; packs do not expire

Prices are the planned launch prices and can change before the paid parts go live.