What is ThinkInsideTheBox?
ThinkInsideTheBox is a 3D physics playground that runs in your browser. You build scenes with rigid bodies and cloth, write GLSL shaders, and control the simulation with JavaScript that runs every frame.
Which physics engine does it use?
Rigid bodies run on Rapier, through @react-three/rapier. Cloth is a separate Verlet simulation with wind and pin points.
What can scripts do?
Scripts are plain JavaScript that run once per simulation frame. They can read every object's position, spawn cubes and spheres, set velocity, apply impulses and torque, change an object's gravity, edit mesh vertices, keep state between frames and add live sliders.
Are scripts from shared scenes safe to run?
Scripts run in a sandbox: a hidden iframe with its own blank origin that starts a Web Worker. Code there cannot read your login session, cookies or browser storage, and cannot make network requests. A script stuck in an endless loop is stopped without freezing the editor. Scripts that come from someone else's scene start switched off, and the editor asks you before turning one on, because a script can move, add and change things in the scene.
Can I write my own shaders?
Yes. The shader editor takes GLSL vertex and fragment shaders and updates the surface as you type. There is also a standalone GLSL playground.
Is it free?
The editor, lessons and tools are free. A free account adds 100 MB of cloud saves. The Creator plan adds 5 GB for $5 a month or $48 a year.
Do I need an account?
No account is needed to open the editor, build scenes, run scripts or share a scene by link. You need a free account to save scenes to the cloud.
How do I share a scene?
The Share button packs the whole scene into a link. Anyone who opens it loads your scene in their own editor, with no sign-up.
Can I export my work?
You can record the canvas as a GIF. There is no export to 3D model formats such as glTF or OBJ.
What do I need to run it?
A modern browser with WebGL2. The editor needs a screen at least 768 pixels wide, so use a laptop, a desktop or a large tablet.
Is there a way to learn the math behind it?
Yes. There are 14 free interactive lessons, from vectors and transforms to shaders, forces and collisions, plus deeper articles on cloth, rigid bodies and Verlet integration.