My First FUSEE App


Create a FUSEE App in VS Code from scratch

NOTE: Developing FUSEE Apps is currently only supported on Windows operating systems.


After a successful FUSEE Installation you might want to create your first FUSEE App in Visual Studio Code.

Create a simple FUSEE App

  1. Create a new empty directory somewhere on your hard-disk. This will contain your first FUSEE App. Name the directory MyFirstFuseeApp.

  2. Open the the directory in Visual Studio Code in one of the following ways.

    • Either Open VS Code, click on “File → Open Folder” from the menu and select the MyFirstFuseeApp directory.
    • Or In Windows Explorer, right-click on the MyFirstFuseeApp directory and select “Open With Code” from the context menu.
    • Or In a Console (Command Prompt or PowerShell), cd to MyFirstFuseeApp and enter code . at the command line.
  3. In Visual Studio Code (with the open folder), Open the integrated terminal (“View → Integrated Terminal” from the menu, Ctrl+` on English keybards, Ctrl+Ö on German keyboards).

  4. In the terminal window at the lower part of VS Code, enter dotnet new fusee. This will populate your MyFirstFuseeApp folder with all necessary sources, assets and project settings needed to build a simple FUSEE app.

Screen Cast: Create a simple FUSEE App

Create a simple FUSEE App


Build and run the App

  1. In Visual Studio Code, open the Debug Side Bar by clicking on the debug symbol (“No Bugs Roadsign”) on the left.

  2. On top of the Debug Side Bar, make sure that the drop-down box next to the green arrow shows Debug in FUSEE Player. If not, select this option from the drop-down box.

  3. Click on the green arrow to build your new FUSEE App and start it in the Debugger. As your new FUSEE App was never built before, the build process might take some time.

  4. As a result, the FUSEE Player application starts and runs the code from your FUSEE application. Try to view the rocket from different angles by clicking and dragging the mouse.

Screen Cast: Build and run the App

Build and run the App

If you’re curious how your FUSEE App works look at the source code file MyFirstFuseeApp.cs that was generated in your project directory.


Publish as Web App and start in Browser

  1. In Visual Studio Code’s Debug Side Bar, select Start in FUSEE Web Player from the drop-down box next to the green arrow.

  2. Click on the green arrow. This will start the following process:

    • If not already done, your project will be built.
    • The compiled code with your App’s functionality will be cross-compiled to JavaScript
    • The resulting JavaScript will be embedded into a cross-compiled version of the FUSEE Player
    • A local Web Server will be started hosting the generated Web App on port 4655 (Hex-Ascii for “FU”).
    • Your System’s default browser will be started on “localhost:4655” to display your FUSEE Web App
  3. As a result, you should see your new web-ified FUSEE App a inside a web browser. Don’t forget to click on the “Stop” button (red square) in Visual Studio Code after closing the browser window.

  4. The “publish as web app” process generated the Web App below MyFirstFuseeApp/pub/Web. Look at the folder contents. Simply copy the entire folder contents to some Web Space to deploy your FUSEE App to the world.

Screen Cast: Publish as Web App and start in Browser

Publish as Web App


Things to know

Now that you created your first FUSEE App, there are some things to know about the build process.

Console commands

All steps mentioned above are individually available as commands from within Visual Studio Code as well as from the command line. Make sure to cd to the root directory of your project. In our example above this would be MyFirstFuseeApp/.

Build/Publish/Run Step Visual Studio Code command Console command line
Build Tasks → Run Build Task… → build dotnet build
Publish Web App Tasks → Run Build Task… → Publish FUSEE Web App fusee publish -p Web
Run Web App Debug Side Bar → Start in FUSEE Web Player fusee server pub/Web
Publish Desktop App Tasks → Run Build Task… → Publish FUSEE Desktop App fusee publish -p Desktop

Publishing as Desktop App

As mentioned in the table above, in addition to publishing to the Web there is also a build step available allowing you to publish your Desktop App (as .exe file). The result will be written to pub/Desktop.

Project folder naming rules

When creating new FUSEE Apps in the way described above, several things in your new project will be named after your project folder. Make sure your folder name obeys to the C# identifier rules. Roughly, that means:

  • First character may be only letter (a-z, A-Z) or underscore (_).
  • Every other character may be letter, underscore or number (0-9).
  • Don’t start the folder name with a number.
  • Don’t use punctuation or other special characters in the folder name, not even a minus (-)!