This guide explains how to launch and use the Aircraft Model Creator through RunModelCreator.jl, the one-click entry point that starts the Julia backend, serves the browser frontend, and opens the app at http://localhost:<port>/.
When you include("RunModelCreator.jl") from a Julia REPL, the script performs the following steps in order:
Activates the Julia environment under 🛫_CREATE_AIRCRAFT_MODEL/ (Project.toml + Manifest.toml).
Bootstraps packages the first time it runs (or whenever Project.toml / Manifest.toml change). A SHA1 stamp under <DEPOT>/openflight/package_bootstrap/ makes subsequent launches skip the slow Pkg.instantiate() step.
Finds a free port starting at 8765. By default it refuses to fall back to another port — keeping the port stable preserves the browser-stored Gemini API key and any cached state. See §5 Troubleshooting to override.
Injects the port into 🛫_CREATE_AIRCRAFT_MODEL/src/js/analysis-setup.js so the frontend's WebSocket client connects to the right server.
Loads the AeroModel module from 🛫_CREATE_AIRCRAFT_MODEL/src/AeroModel/AeroModel.jl.
Starts the HTTP + WebSocket server asynchronously.
Launches your default browser at http://localhost:<port>/. On Windows it tries the OS default first, then Edge → Chrome → Firefox; on macOS, Safari → Chrome → Firefox; on Linux, xdg-open → Chrome → Chromium → Firefox.
Blocks on the server task. Press Ctrl-C in the REPL to stop.
Julia — a working Julia install (download from julialang.org). The first launch will install required packages automatically: StaticArrays, HTTP, Sockets, JSON, MsgPack, Printf.
Web browser — a modern Chromium-based browser (Edge, Chrome) or Firefox. The frontend uses Babylon.js for 3D rendering and a binary MessagePack WebSocket protocol.
Project files — the complete OpenFLIGHT folder structure as shipped, with 🛫_CREATE_AIRCRAFT_MODEL/ intact next to RunModelCreator.jl.
(Optional) Gemini API key — the frontend's AI-assistant panel uses Google Gemini. The key is stored in the browser's local storage; the stable port is what lets the key survive restarts.
From a Julia REPL opened in the project root (the folder that contains RunModelCreator.jl):
include("RunModelCreator.jl")
Expected console output on a warm start (environment already instantiated):
============================================================
Aircraft Model Creator - Startup
============================================================
Julia environment already instantiated — skipping Pkg.instantiate().
All packages ready.
HTTP/WebSocket server will use port: 8765
Injected port 8765 into analysis-setup.js
Loading AeroModel module...
AeroModel module loaded.
Starting AeroModel HTTP + WebSocket server on port 8765...
Press Ctrl-C to stop.
Launching browser at http://localhost:8765/ ...
If the browser does not open automatically, manually point it at the URL printed on the last line.
Once the page loads at http://localhost:<port>/, you'll see the Aircraft Model Creator workspace. The main areas are:
3D viewport — interactive Babylon.js scene where the aircraft is rendered.
Component panel — add / edit lifting surfaces, fuselage, propulsion, etc.
Analysis & results panel — runs VLM (Vortex Lattice Method) and tabular aero solvers via the Julia backend over WebSocket.
Gemini assistant panel — natural-language helper backed by Google Gemini (requires API key, stored in browser local storage).
Export panel — save the model to disk, including .glb mesh and OpenFLIGHT-compatible aero/prop YAML files.
[IMAGE: Full-page screenshot of the Model Creator UI with each panel labeled (3D viewport, component tree, analysis/results, Gemini assistant, export controls).]
Create or load an aircraft component tree (wing, horizontal/vertical tail, fuselage, engine).
Adjust geometry — span, chord, sweep, dihedral, twist, airfoil — directly in the panel; the 3D view updates live.
Run an analysis — the frontend sends a MessagePack request to the Julia backend, which runs VLM and returns lift/drag/moment polars and stability derivatives.
Inspect results — review polars, induced-drag plots, stability derivatives, and the inertia ellipsoid in the results panel.
Export — write the aircraft folder (.glb + .tabular.aero_prop.yaml + render settings) into 🏭_HANGAR/ so the OpenFLIGHT simulator can fly it.
By design, RunModelCreator.jl will not silently switch to a different port — keeping the port stable is what preserves the browser-stored Gemini API key. You will see:
ERROR: Port 8765 is already in use. Close the existing Model Creator server,
or set OPENFLIGHT_ALLOW_PORT_FALLBACK=true to use another port. ...
Fix (preferred): find and stop the previous Julia / Model Creator process holding the port, then re-run.
Fix (override): allow the script to scan up to 200 ports for a free one:
ENV["OPENFLIGHT_ALLOW_PORT_FALLBACK"] = "true"
include("RunModelCreator.jl")
Note: with a fallback port, the browser will treat it as a different origin and your stored Gemini API key will not carry over.
The script tries the OS default first, then Edge → Chrome → Firefox (Windows). If all attempts fail, it prints:
Could not auto-launch browser. Please open manually:
http://localhost:<port>/
Just paste that URL into any modern browser.
The script rewrites the line var aeromodel_port = …; in 🛫_CREATE_AIRCRAFT_MODEL/src/js/analysis-setup.js on every launch. If you see a Could not find 'var aeromodel_port = …' warning, the line was edited or removed — restore it to:
var aeromodel_port = 8765; // Auto-set by RunModelCreator.jl
…then re-run. The exact integer doesn't matter; the script will overwrite it.
That means the bootstrap stamp file is missing or the environment hash changes between runs. Check:
The depot is writable: <DEPOT>/openflight/package_bootstrap/ should be created on first run.
Project.toml / Manifest.toml are not being modified by another tool between launches (some editors reformat TOML files on save).
Press Ctrl-C in the Julia REPL where RunModelCreator.jl is running. The server task will be interrupted and the REPL will return to its prompt. Closing the browser tab alone does not stop the backend.
RunModelCreator.jl — this entry point.
🛫_CREATE_AIRCRAFT_MODEL/Project.toml — Julia environment for the Model Creator.
🛫_CREATE_AIRCRAFT_MODEL/src/AeroModel/AeroModel.jl — server module loaded at step 5.
🛫_CREATE_AIRCRAFT_MODEL/src/js/analysis-setup.js — frontend file the port is injected into.
🛫_CREATE_AIRCRAFT_MODEL/create_aircraft_model.html — frontend page served at /.
DOCS/USER_GUIDE.md — companion guide for the OpenFLIGHT simulator (flying an aircraft once it has been exported to 🏭_HANGAR/).