Creating a 3D Scene with Three.js in Svelte

A step-by-step guide to integrating the popular 3D library Three.js into a Svelte 5 component to create interactive WebGL scenes.

6/22/2025

Bringing 3D to the Web with Svelte

Three.js is the leading library for creating and displaying 3D computer graphics in a web browser. It simplifies the complexities of WebGL, providing a high-level API to build everything from simple geometric shapes to complex, photorealistic scenes. When paired with Svelte, it becomes a potent combination for building performant, interactive, and visually stunning web applications.

Svelte’s component-based nature and efficient reactivity model make it an ideal partner for managing the state and lifecycle of a 3D scene, while Three.js handles the heavy lifting of rendering.

Live Demonstration

Below is a live, interactive 3D scene rendered by a Svelte component using Three.js. You can use your mouse to rotate and zoom, exploring the object from all angles.

The Integration Process

Integrating Three.js into a Svelte component involves a few key steps, managed within Svelte’s lifecycle functions.

1. Setup in onMount: All Three.js setup code must run on the client after the component’s DOM elements are available. Svelte’s onMount is the perfect place for this. It ensures that our code, which needs a <canvas> element to render on, executes at the right time.

2. Canvas Binding: We create a <canvas> element in our Svelte template and use bind:this to get a direct reference to it in our script. This reference is then passed to the Three.js renderer.

   <canvas bind:this={canvas}></canvas>

3. Core Three.js Objects: Inside onMount, we initialize the fundamental Three.js objects:

   • THREE.Scene: The container for all objects, lights, and cameras.
   • THREE.Camera: Defines the viewpoint. We use a PerspectiveCamera for a realistic 3D view.
   • THREE.WebGLRenderer: Does the work of rendering the scene onto the canvas.

4. Animation Loop: A 3D scene is not static. We create an animate function that calls itself with requestAnimationFrame. Inside this loop, we update object rotations, handle controls, and call renderer.render(scene, camera) to draw the new frame.

5. Cleanup: It’s crucial to clean up resources to prevent memory leaks when the component is unmounted. The function returned from onMount is where we call the dispose() method on the Three.js renderer, geometries, and materials.

This structured approach encapsulates the 3D logic entirely within a Svelte component, making it reusable and easy to manage within your larger SvelteKit application.