Model physical systems
the way engineers think.
BondGraph Studio is a WYSIWYG bond graph editor for multi-domain dynamic systems — mechanical, hydraulic, electrical, thermal, magnetic — with causality analysis, simulation, and one-click export to Modelica, DAE and ODE. Built for MBSE workflows and for the AI agents that now sit alongside them.
No sign-up. Your models stay in your browser.
Engineers who model the physical world
Bond graphs unify every energetic domain on the same canvas — the lingua franca for multi-physics MBSE.
Control & mechatronics
Plant + actuator + sensor in one diagram. Linearise around an operating point, hand the state-space to your controller stack.
Hydraulic & fluid power
Pumps, valves, accumulators and lines as bond-graph primitives. No more rewriting effort/flow conventions across tools.
Thermal & energy systems
Heat capacities, conductances and sources — built-in cottage and data-center examples to start from.
Systems engineering & MBSE
BGIF (open JSON IR) makes models version-controllable and toolchain-portable. Trace requirements through SPDM steps.
A complete bond-graph workbench
Everything you need from sketch to validated simulation, without leaving the browser.
Multi-domain modelling
R, C, I, TF, GY, 0, 1 across mechanical, hydraulic, electrical, thermal, magnetic.
Causality analysis
SCAP runs as you wire. See effort/flow assignment and over-/under-constrained junctions immediately.
Built-in simulation
Native ODE/DAE solver in the browser with event detection, plots and CSV export.
Equation export
Symbolic DAE, ODE and Modelica — copy-paste into OpenModelica, Dymola or your own pipeline.
Linearisation & frequency
Numeric Jacobians, eigenvalues, Bode and step response around any operating point.
Reusable component libraries
BGLIB v1 packs of subsystems with SVG icons. Import, export, share across projects.
Your AI agent gets the same tools you do
A native Model Context Protocol endpoint exposes the simulator, validator, analysis and editing tools — so Claude, Cursor, ChatGPT or your own agent can build and run models alongside you.
MCP endpoint
Point any MCP-capable client at /api/mcp. Tools include simulate, validate, linearize, sweep, edit, render, and the full BGLIB library API.
# Discover tools
curl -X POST https://xn--lda.se/api/mcp \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'
# Run a simulation
curl -X POST https://xn--lda.se/api/mcp \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","id":2,"method":"tools/call",
"params":{"name":"simulate",
"arguments":{"model":"rc_circuit","tEnd":5}}}'From idea to integrated model in minutes
- step 1ModelDrag elements, wire bonds, set parameters.
- step 2SimulateRun native ODE/DAE solver, plot, export CSV.
- step 3ExportModelica · DAE · ODE · BGIF · SVG · PNG.
- step 4IntegrateDrop into Modelica tools or call from agents.
Frequently asked questions
Where are my models stored?
In your browser's local storage. The app does not upload your models to any server. The public simulation API only runs the model you POST to it for the duration of the request.
Is it free?
Yes. BondGraph Studio is free to use in your browser. Heavier integrations and on-prem deployments are on the roadmap.
Which solvers and formats are supported?
A built-in adaptive ODE/DAE solver with event detection runs in the browser. Models export to Modelica (validated against OpenModelica and Rumoca), symbolic DAE, ODE, and the open BGIF JSON intermediate representation.
How do AI agents connect?
Via the Model Context Protocol endpoint at /api/mcp, or the OpenAPI 3.1 HTTP API at /api/public/*. Any MCP-capable client (Claude Desktop, Cursor, custom) can use it directly.
Does it work offline?
The editor and built-in simulator run entirely client-side, so once the page is loaded most features work without a network connection.
Open a fresh canvas and start modelling.
No install, no sign-up. Bring your AI agent if you like.