ModelScript is a comprehensive Modelica compilation, simulation, optimization, and visualization framework. It provides a robust engine for parsing Modelica code, performing semantic analysis, flattening models, simulating dynamic systems, solving optimal control problems, and rendering interactive diagrams — all from the browser or the command line.
This project is a monorepo managed with Lerna, Nx, and npm workspaces.
| Package | Description |
|---|---|
@modelscript/core | Compiler engine — parsing, semantic analysis, flattening, simulation, linting |
@modelscript/cosim | Co-simulation orchestration and SSP archive generation |
@modelscript/ecad | ECAD integration utilities for ModelScript |
@modelscript/fmi | Functional Mock-up Interface (FMI) support |
@modelscript/lsp | Language Server Protocol — completions, hover, diagnostics, formatting, colors |
@modelscript/mcp | Model Context Protocol implementation |
@modelscript/modelica | Tree-sitter grammar (native + WASM) and polyglot queries for Modelica |
@modelscript/optimizer | Direct collocation optimizer for optimal control problems |
@modelscript/polyglot | AST querying and transformation utilities |
@modelscript/simulator | ODE/DAE solver engine (Pantelides index reduction, BLT ordering) |
@modelscript/symbolics | Symbolic manipulation engine for equations |
@modelscript/sysml2 | SysML v2 AST querying and handling |
@modelscript/utils | Common utility functions across the ModelScript monorepo |
@modelscript/cli | msc command-line interface — flatten, simulate, optimize, lint, render, and more |
@modelscript/api | REST API server — simulation, publishing, GraphQL, SPARQL, and RDF |
@modelscript/morsel | Visual Modelica editor — code editing, diagram viewer, simulation, and plotting |
@modelscript/site | Main modelscript.org website |
@modelscript/web | Web frontend for browsing and exploring Modelica libraries |
@modelscript/ide | VS Code Web IDE — browser-based Modelica development environment |
@modelscript/vscode | VS Code extension — syntax highlighting, LSP client, diagram view |
- Accurate Parsing — custom Tree-sitter grammar for efficient, incremental parsing
- Semantic Analysis — full scope and name resolution for complex Modelica hierarchies
- Flattening — transforms hierarchical models into flat Differential Algebraic Equations (DAE)
- Simulation — ODE/DAE solver with Pantelides index reduction and BLT ordering
- Optimization — optimal control problem solver using direct collocation
- Diagram Rendering — interactive SVG diagrams and X6-based visual layouts with auto-placement
- Language Server — completions, hover, diagnostics, formatting, and color provider
- Linting — 15+ lint rules covering syntax, types, semantics, and equations
- Modelica Scripting — interpreter for evaluating Modelica expressions and algorithms
- i18n Support — extracting translatable strings from Modelica models
- Node.js ≥ 24 (see
.nvmrc) - emsdk (required for building the Tree-sitter WASM parser):
git clone https://github.com/emscripten-core/emsdk.git cd emsdk ./emsdk install latest ./emsdk activate latest source ./emsdk_env.sh
git clone https://github.com/modelscript/modelscript.git
cd modelscript
npm installBuild all packages (in dependency order via Nx):
npm run buildStart all services concurrently:
npm run devThis launches:
| Service | URL | Description |
|---|---|---|
| Morsel (editor) | http://localhost:3002 | Visual editor with diagrams and simulation |
| Web (library browser) | http://localhost:3001 | Browse and explore Modelica libraries |
| API | http://localhost:3000 | REST API for simulation, publishing, queries |
| IDE (VS Code Web) | http://localhost:3003 | Browser-based VS Code with Modelica support |
The IDE includes a browser-local AI assistant powered by WebLLM (Qwen3-0.6B). To enable it, download the model weights (~350 MB, one-time):
npm run download-model --workspace=@modelscript/ideOnce downloaded, restart npm run dev and open the ModelScript AI panel in the IDE sidebar.
After building, the CLI is available as msc:
# Flatten a model to DAE
npx msc flatten Modelica.Electrical.Analog.Examples.CauerLowPassAnalog path/to/MSL
# Simulate a model (outputs CSV by default)
npx msc simulate BouncingBall model.mo --stop-time 5
# Simulate with JSON output
npx msc simulate BouncingBall model.mo --format json
# Solve an optimal control problem
npx msc optimize MyModel model.mo \
--objective "u^2" --controls "u" --control-bounds "u:-1:1" --stop-time 10
# Lint Modelica files
npx msc lint model.mo
# Render a diagram to SVG (outputs to stdout)
npx msc render MyModel model.mo > diagram.svgRun the test suite across all packages:
npm testnpm run lintnpm run formatPre-built images are published to the GitHub Container Registry on every push to main.
Run the latest images without building:
docker compose pull # Pull latest images from ghcr.io/modelscript/*
docker compose up -d # Start containers
docker compose down # Stop containers
docker compose logs -f # Tail logsTo build from source instead:
npm run docker:build # Build images locally
npm run docker:up # Start containers| Service | Port | URL |
|---|---|---|
| API | 3000 | http://localhost:3000 |
| Morsel | 3002 | http://localhost:3002 |
| Web | 3001 | http://localhost:3001 |
| IDE | 3003 | http://localhost:3003 |
ModelScript is licensed under the AGPL-3.0-or-later. See COPYING for more details.