Cornell torus

This demo is part of my “Three.js in a Hurry” collection—an effort to help fellow spatial computing folks get up to speed quickly with the Three.js WebGL-based 3D rendering library. This example contains a rotating torus knot inside a Cornell Box rendered live, complete with interactive controls for adjusting various parameters. The code is clean, commented, and contains links to relevant third-party documentation. This demonstration code is live at http://stewartsmith.io/studies/cornell-torus/.

How to: Download this code package

If you’re not familiar with GitHub, the easiest way to download this code package is to click the green “↓ Code” button near the top of this page. Choose the “Download ZIP” option.

How to: Run this from your Mac desktop

Sadly, you cannot just drag and drop the index.html file onto a browser window to view this application from your own Macintosh desktop. You’ll need to spin up a server and view the application from a URL like http://localhost:8000/ instead. But don’t worry—that’s easy!

1. Open the Terminal application. (Just hit ⌘ + Spacebar, then type “terminal” to search for it on your Mac. Once found, hit Enter to open it.)

2. Type cd  (yes, with that space after it), then drag and drop this whole code package folder that you’ve downloaded onto the Terminal window—it will fill in the folder’s full path address for you. (You’ll see something like cd ~/YourName/Downloads/cornell-torus/.) Now hit Enter to tell Terminal it must change directories to that folder.

3. Paste this into Terminal, then hit Enter: python -m SimpleHTTPServer 8000. You are now running a web server on port 8000. (You could instead use a different number to listen on a different port. This is handy if you need many servers running at once; each will need to listen to a different port.)

4. Now you can visit this website at http://localhost:8000 and everything should be fine 👍

When you’re ready to shut down the server, go back to Terminal and tap Control + C. That’s all!

For more information on running a barebones local server, (including Python 3 commands) see Mozilla’s Set up a local testing server article.