Three.js is an open-source JavaScript library for creating and displaying 3D graphics on the web. It provides tools for scenes, cameras, geometry, materials, lighting and animation.
The scene, the viewpoint and the resulting image
Think of a small stage. The scene contains objects and their relationships; a camera defines the view; a renderer draws that view into an image on the page. Three.js gives developers a way to describe and update these pieces. In the animation, a cube changes orientation in the scene, then the drawn view changes with it. The diagram is a simplified explanation of rendering, not a screenshot of Painta’s editor.
A library is not the same thing as an AR experience
Three.js can draw an animated sculpture in a browser without knowing where a physical painting is. An AR experience needs additional input that relates the virtual view or content to the surroundings. WebAR describes how the experience is delivered; WebXR is a browser API for supported immersive capabilities. Image-tracking software has another job: estimating the pose of a known image. These pieces can work together, but their names are not interchangeable.
What an artist needs to understand
You do not need to write JavaScript to prepare a well-structured 3D artwork. The useful vocabulary is already familiar: mesh for shape, material for surface appearance, scene graph for relationships, and animation for changes over time. Three.js helps a developer put those elements on screen. A compatible loader can read assets such as GLB files; support for a particular extension or effect still depends on the application and its version.
Where Painta fits
Painta uses Three.js in its 3D stack and provides a visual editor around the experience-building workflow. For the artist, this makes model preparation more relevant than writing a rendering loop: check materials, scale, animation and file weight before importing. A model that looks good on a desktop still needs a check in the intended mobile viewer. The library handles drawing, while asset quality, tracking, browser support and the surrounding product determine the visitor’s full experience.
Related concepts and further reading
For the graphics interfaces beneath a rendering library, compare WebGL and WebGPU. Support for an API depends on the application and device, not merely on using Three.js.