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Using Bitbybit with ThreeJS

This guide will walk you through setting up and using the @bitbybit-dev/threejs package to integrate Bitbybit's 3D CAD functionalities into your ThreeJS applications. We'll use Vite as our build tool, which simplifies the setup process.

The @bitbybit-dev/threejs package conveniently includes three as a dependency, so you don't need to install it separately.

Prerequisites​

  • Node.js and npm (or yarn) installed.
  • A basic understanding of TypeScript and ThreeJS.

Example on Bitbybit Github Repo​

1. Project Setup with Vite​

First, create a new Vite project with a TypeScript template:

npm create vite@latest my-bitbybit-threejs-app -- --template vanilla-ts
# or: yarn create vite my-bitbybit-threejs-app --template vanilla-ts

cd my-bitbybit-threejs-app

Next, install the Bitbybit ThreeJS package and its necessary worker dependencies:

npm install @bitbybit-dev/threejs
# or: yarn add @bitbybit-dev/threejs
Why these packages?
  • @bitbybit-dev/threejs: The main library for integrating Bitbybit with ThreeJS. It also installs these main packages listed below.
  • three: Provides main game engine to be used with this demo.
  • @bitbybit-dev/core: Collects all kernel web worker libraries into coherent bitbybit base. It also includes some higher level functionality.
  • @bitbybit-dev/occt-worker: Provides the OpenCascade (OCCT) geometry kernel running in a Web Worker.
  • @bitbybit-dev/jscad-worker: Provides the JSCAD geometry kernel running in a Web Worker.
  • @bitbybit-dev/manifold-worker: Provides the Manifold geometry kernel running in a Web Worker.
  • @bitbybit-dev/occt: Communicates with worker and contains main logic of OCCT geometry kernel - can be used in non web-worker environments.
  • @bitbybit-dev/jscad: Communicates with worker and contains main logic of JSCAD geometry kernel - can be used in non web-worker environments.
  • @bitbybit-dev/manifold: Communicates with worker and contains main logic of Manifold geometry kernel - can be used in non web-worker environments.
  • @bitbybit-dev/base: Contains base geometry types and functions, such as vector operations, matrix transformations, math and list helpers - they can be used in all kernels.

2. HTML Structure​

Modify your index.html file in the project root to include a <canvas> element where the ThreeJS scene will be rendered:

index.html
<!DOCTYPE html>
<html lang="en">
  <head>
      <meta charset="UTF-8" />
      <link rel="icon" type="image/svg+xml" href="/vite.svg" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0" />
      <title>Bitbybit & ThreeJS Example</title>
  </head>
  <body>
      <canvas id="three-canvas"></canvas>
      <script type="module" src="/src/main.ts"></script>
  </body>
</html>

This is a standard HTML setup. The key parts are:

  • <canvas id="three-canvas"></canvas>: This is where our 3D scene will be drawn.
  • <script type="module" src="/src/main.ts"></script>: This loads our main TypeScript application logic.

3. Setting up Web Workers​

Bitbybit utilizes Web Workers to run computationally intensive geometry kernels (OCCT, JSCAD, Manifold) off the main browser thread, preventing UI freezes. You need to create simple worker files that initialize these kernels.

Create a workers directory inside your src folder (src/workers/).

src/workers/occt.worker.ts
import initOpenCascade from '@bitbybit-dev/occt/bitbybit-dev-occt/cdn';
import type { OpenCascadeInstance } from '@bitbybit-dev/occt/bitbybit-dev-occt/bitbybit-dev-occt.js';
import {
initializationComplete,
onMessageInput,
} from '@bitbybit-dev/occt-worker';

// Initialize OpenCascade (OCCT)
initOpenCascade().then((occ: OpenCascadeInstance) => {
  // Notify the main thread that OCCT is ready
  initializationComplete(occ, undefined);
});

// Listen for messages from the main thread
addEventListener('message', ({ data }) => {
  // Process messages using the occt-worker helper
  onMessageInput(data, postMessage);
});

Explanation:

  • Imports initOpenCascade to load the OCCT WebAssembly module.
  • Calls initializationComplete once OCCT is loaded, signaling to the main Bitbybit instance that this kernel is ready.
  • onMessageInput handles communication between the main thread and the OCCT worker.
Worker File Location

Vite handles these worker files automatically when you instantiate them using new Worker(new URL('./path/to/worker.ts', import.meta.url), ...). Ensure the paths in main.ts correctly point to these files within your src/workers/ directory.

4. Main Application Logic (main.ts)​

Replace the content of src/main.ts with the following:

src/main.ts
import './style.css'; // Basic styling
import { BitByBitBase, Inputs } from '@bitbybit-dev/threejs';
import { OccStateEnum } from '@bitbybit-dev/occt-worker';
import { JscadStateEnum } from '@bitbybit-dev/jscad-worker';
import { ManifoldStateEnum } from '@bitbybit-dev/manifold-worker';

import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls';
import {
  Color,
  Group,
  HemisphereLight,
  PerspectiveCamera,
  Scene,
  Vector3,
  WebGLRenderer,
} from 'three';
import { first, firstValueFrom, tap } from 'rxjs';

// Define an interface for kernel options
interface KernelOptions {
  enableOCCT: boolean;
  enableJSCAD: boolean;
  enableManifold: boolean;
}

// --- 1. Main Application Entry Point ---
start();

async function start() {
  // Initialize basic ThreeJS scene
  const { scene } = initThreeJS();

  // Create an instance of BitByBitBase for ThreeJS
  const bitbybit = new BitByBitBase();

  // --- 2. Configure and Initialize Kernels ---
  // Users can control which kernels are loaded
  const kernelOptions: KernelOptions = {
      enableOCCT: true,
      enableJSCAD: true,
      enableManifold: true,
  };
  // Initialize Bitbybit with the selected kernels
  await initWithKernels(scene, bitbybit, kernelOptions);

  // --- 3. Create Geometry with Active Kernels ---
  if (kernelOptions.enableOCCT) {
      await createOCCTGeometry(bitbybit, '#ff0000'); // Red
  }
  if (kernelOptions.enableManifold) {
      await createManifoldGeometry(bitbybit, '#00ff00'); // Green
  }
  if (kernelOptions.enableJSCAD) {
      await createJSCADGeometry(bitbybit, '#0000ff'); // Blue
  }
}

// --- 4. ThreeJS Scene Initialization ---
function initThreeJS() {
  const domNode = document.getElementById('three-canvas') as HTMLCanvasElement;

  const camera = new PerspectiveCamera(
      70,
      window.innerWidth / window.innerHeight,
      0.1, // Adjusted near plane for typical scenes
      1000
  );
  const scene = new Scene();
  scene.background = new Color(0x1a1c1f); // Set background color

  const light = new HemisphereLight(0xffffff, 0x444444, 2); // Adjusted intensity
  scene.add(light);

  const renderer = new WebGLRenderer({ antialias: true, canvas: domNode });
  renderer.setSize(window.innerWidth, window.innerHeight);
  // renderer.setPixelRatio(window.devicePixelRatio); // Consider devicePixelRatio for sharpness

  camera.position.set(50, 50, 100); // Adjusted camera position
  camera.lookAt(0,0,0);

  const controls = new OrbitControls(camera, renderer.domElement);
  controls.enableDamping = true;
  controls.dampingFactor = 0.05; // Smoother damping
  controls.target.set(0, 0, 0); // Ensure controls target the origin
  controls.update(); // Initial update

  const onWindowResize = () => {
      camera.aspect = window.innerWidth / window.innerHeight;
      camera.updateProjectionMatrix();
      renderer.setSize(window.innerWidth, window.innerHeight);
  };
  window.addEventListener('resize', onWindowResize, false);

  const animate = () => {
      controls.update(); // Important for damping
      renderer.render(scene, camera);
  };
  renderer.setAnimationLoop(animate);

  return { scene, camera, renderer }; // Return renderer and camera if needed elsewhere
}

// --- 5. Bitbybit Kernel Initialization Logic ---
async function initWithKernels(
  scene: Scene,
  bitbybit: BitByBitBase,
  options: KernelOptions
): Promise<{ message: string }> {
  let occtWorkerInstance: Worker | undefined;
  let jscadWorkerInstance: Worker | undefined;
  let manifoldWorkerInstance: Worker | undefined;

  // 1. Conditionally create worker instances
  if (options.enableOCCT) {
      occtWorkerInstance = new Worker(
      new URL('./workers/occt.worker.ts', import.meta.url),
      { name: 'OCC_WORKER', type: 'module' }
      );
  }
  if (options.enableJSCAD) {
      jscadWorkerInstance = new Worker(
      new URL('./workers/jscad.worker.ts', import.meta.url),
      { name: 'JSCAD_WORKER', type: 'module' }
      );
  }
  if (options.enableManifold) {
      manifoldWorkerInstance = new Worker(
      new URL('./workers/manifold.worker.ts', import.meta.url),
      { name: 'MANIFOLD_WORKER', type: 'module' }
      );
  }

  // 2. Initialize Bitbybit
  await bitbybit.init(
      scene,
      occtWorkerInstance,
      jscadWorkerInstance,
      manifoldWorkerInstance
  );

  // 3. Collect promises for kernel initializations
  const initializationPromises: Promise<void>[] = [];
  let anyKernelSelectedForInit = false;

  if (options.enableOCCT) {
      anyKernelSelectedForInit = true;
      if (bitbybit.occtWorkerManager) {
      initializationPromises.push(
          firstValueFrom(
          bitbybit.occtWorkerManager.occWorkerState$.pipe(
              first((s) => s.state === OccStateEnum.initialised),
              tap(() => console.log('OCCT Initialized'))
          )
          ).then(() => {}) // Ensure the promise resolves to void for Promise.all
      );
      } else {
      console.warn(
          'OCCT enabled in options, but occtWorkerManager not found after init.'
      );
      }
  }

  if (options.enableJSCAD) {
      anyKernelSelectedForInit = true;
      if (bitbybit.jscadWorkerManager) {
      initializationPromises.push(
          firstValueFrom(
          bitbybit.jscadWorkerManager.jscadWorkerState$.pipe(
              first((s) => s.state === JscadStateEnum.initialised),
              tap(() => console.log('JSCAD Initialized'))
          )
          ).then(() => {})
      );
      } else {
      console.warn(
          'JSCAD enabled in options, but jscadWorkerManager not found after init.'
      );
      }
  }

  if (options.enableManifold) {
      anyKernelSelectedForInit = true;
      if (bitbybit.manifoldWorkerManager) {
      initializationPromises.push(
          firstValueFrom(
          bitbybit.manifoldWorkerManager.manifoldWorkerState$.pipe(
              first((s) => s.state === ManifoldStateEnum.initialised),
              tap(() => console.log('Manifold Initialized'))
          )
          ).then(() => {})
      );
      } else {
      console.warn(
          'Manifold enabled in options, but manifoldWorkerManager not found after init.'
      );
      }
  }

  // 4. Wait for selected & available kernels or handle no selection/availability
  if (!anyKernelSelectedForInit) {
      console.log('No kernels selected for initialization.');
      return { message: 'No kernels selected for initialization.' };
  }

  if (initializationPromises.length === 0) {
      // Kernels were selected, but none were awaitable (e.g., managers missing for all selected)
      console.log(
      'Kernels were selected, but none had managers available for awaiting initialization.'
      );
      return {
      message: 'Selected kernels were not awaitable for initialization state.',
      };
  }

  await Promise.all(initializationPromises);
  console.log('Selected and awaitable kernels initialized:', options);
  return {
      message: 'Selected and awaitable kernels initialized successfully.',
  };
}

// --- 6. Geometry Creation Functions (Examples) ---
async function createOCCTGeometry(bitbybit: BitByBitBase, color: string) {
  console.log('Creating OCCT geometry...');
  const cubeOptions = new Inputs.OCCT.CubeDto();
  cubeOptions.size = 25;
  cubeOptions.center = [0, 0, 0];

  const cube = await bitbybit.occt.shapes.solid.createCube(cubeOptions);

  const filletOptions = new Inputs.OCCT.FilletDto<Inputs.OCCT.TopoDSShapePointer>();
  filletOptions.shape = cube;
  filletOptions.radius = 4;
  const roundedCube = await bitbybit.occt.fillets.filletEdges(filletOptions);

  const drawOptions = new Inputs.Draw.DrawOcctShapeOptions();
  drawOptions.faceColour = color;
  await bitbybit.draw.drawAnyAsync({
      entity: roundedCube,
      options: drawOptions,
  });
  console.log('OCCT geometry created and drawn.');
}

async function createManifoldGeometry(bitbybit: BitByBitBase, color: string) {
  console.log('Creating Manifold geometry...');
  const sphereOptions = new Inputs.Manifold.SphereDto();
  sphereOptions.radius = 15;
  const sphere = await bitbybit.manifold.manifold.shapes.sphere(sphereOptions);

  const cubeOptions = new Inputs.Manifold.CubeDto();
  cubeOptions.size = 25;
  const cube = await bitbybit.manifold.manifold.shapes.cube(cubeOptions);

  const diffedShape = await bitbybit.manifold.manifold.booleans.differenceTwo({
      manifold1: cube,
      manifold2: sphere,
  });

  const translationOptions = new Inputs.Manifold.TranslateDto<Inputs.Manifold.ManifoldPointer>();
  translationOptions.manifold = diffedShape;
  translationOptions.vector = [0, -40, 0]; // Position below OCCT
  const movedShape = await bitbybit.manifold.manifold.transforms.translate(
      translationOptions
  );

  const drawOptions = new Inputs.Draw.DrawManifoldOrCrossSectionOptions();
  drawOptions.faceColour = color;
  await bitbybit.draw.drawAnyAsync({
      entity: movedShape,
      options: drawOptions,
  });
  console.log('Manifold geometry created and drawn.');
}

async function createJSCADGeometry(bitbybit: BitByBitBase, color: string) {
  console.log('Creating JSCAD geometry...');
  const geodesicSphereOptions = new Inputs.JSCAD.GeodesicSphereDto();
  geodesicSphereOptions.radius = 15;
  geodesicSphereOptions.center = [0, 40, 0]; // Position above OCCT
  const geodesicSphere = await bitbybit.jscad.shapes.geodesicSphere(
      geodesicSphereOptions
  );

  // Example: Create another simple sphere for a boolean operation
  const sphereOptions = new Inputs.JSCAD.SphereDto();
  sphereOptions.radius = 10; // Smaller sphere
  sphereOptions.center = [5, 45, 0]; // Slightly offset
  const simpleSphere = await bitbybit.jscad.shapes.sphere(sphereOptions);

  const unionOptions = new Inputs.JSCAD.BooleanTwoObjectsDto();
  unionOptions.first = geodesicSphere;
  unionOptions.second = simpleSphere;
  const unionShape = await bitbybit.jscad.booleans.unionTwo(unionOptions);

  const drawOptions = new Inputs.Draw.DrawBasicGeometryOptions();
  drawOptions.colours = color; // Note: 'colours' for JSCAD draw options
  await bitbybit.draw.drawAnyAsync({
      entity: unionShape,
      options: drawOptions,
  });
  console.log('JSCAD geometry created and drawn.');
}

Explanation of main.ts:​

  1. Imports:

    • BitByBitBase and Inputs: Core components from @bitbybit-dev/threejs. Inputs provides DTOs (Data Transfer Objects) for specifying parameters for geometry operations.
    • ...StateEnum: Enums used to check the initialization state of each kernel worker.
    • Standard ThreeJS modules for scene setup.
    • first from rxjs: Used to easily subscribe to the first emission of a kernel's state.

  2. KernelOptions Interface: Defines the structure for selecting which kernels to initialize.

  3. start() function (Main Entry Point):

    • Calls initThreeJS() to set up the basic ThreeJS scene, camera, renderer, and controls.
    • Creates an instance of BitByBitBase.
    • kernelOptions: This object is key. By setting enableOCCT, enableJSCAD, and enableManifold to true or false, you control which kernels Bitbybit attempts to initialize. This allows for optimizing load times and resource usage if not all kernels are needed.
    • Calls initWithKernels() to initialize Bitbybit with the selected kernels.
    • Conditionally calls geometry creation functions (createOCCTGeometry, createManifoldGeometry, createJSCADGeometry) based on which kernels were enabled and successfully initialized.

  4. initThreeJS() function:

    • Standard ThreeJS boilerplate: sets up the Scene, PerspectiveCamera, WebGLRenderer, HemisphereLight, and OrbitControls.
    • Includes a window resize listener and an animation loop.

  5. initWithKernels() function:

    • This is the core of Bitbybit's initialization.
    • It conditionally creates Worker instances for OCCT, JSCAD, and Manifold based on the options passed in. The new URL('./workers/worker-name.worker.ts', import.meta.url) syntax is Vite's way of correctly bundling and referencing web worker files.
    • Calls await bitbybit.init(scene, occtWorkerInstance, jscadWorkerInstance, manifoldWorkerInstance). BitByBitBase can handle undefined for worker instances it shouldn't initialize.
    • It then uses RxJS pipe(first(...)) to subscribe to the state observables of each enabled kernel (occWorkerState$, jscadWorkerState$, manifoldWorkerState$).
    • The Promise resolves only after all selected and enabled kernels have emitted an initialised state. This ensures that you don't try to use a kernel before it's ready.

  6. Geometry Creation Functions (createOCCTGeometry, createManifoldGeometry, createJSCADGeometry):

    • These are example functions demonstrating how to use the APIs for each kernel.
    • Inputs DTOs: You'll notice the use of Inputs.OCCT.CubeDto(), Inputs.Manifold.SphereDto(), etc. These objects are used to pass parameters to Bitbybit's geometry creation and modification functions. They provide type safety and often mirror the inputs you'd find in a visual programming environment. Intellisense (auto-completion in your IDE) will be very helpful here.
    • API Structure: Operations are typically namespaced under bitbybit.occt.*, bitbybit.manifold.*, and bitbybit.jscad.*.
    • Drawing: After creating a geometric entity, bitbybit.draw.drawAnyAsync() is used to render it into the ThreeJS scene. Different kernels might have slightly different drawing option DTOs (e.g., DrawOcctShapeOptions, DrawManifoldOrCrossSectionOptions, DrawBasicGeometryOptions).

5. Basic Styling (Optional)​

Create an src/style.css file if you haven't already:

src/style.css
body {
  margin: 0;
  overflow: hidden; /* Prevent scrollbars from canvas */
  background-color: #1a1c1f;
}

#three-canvas {
  display: block;
  width: 100vw;
  height: 100vh;
}

6. Running the Application​

npm run dev
# or: yarn dev

Vite will start a development server, and you should see a browser window open with your ThreeJS scene. If all kernels were enabled, you'll see three distinct shapes:

  • A red, filleted cube (OCCT) at the origin.
  • A green, subtracted shape (Manifold) positioned below the OCCT shape.
  • A blue, unioned sphere shape (JSCAD) positioned above the OCCT shape.

Check your browser's developer console for logs indicating the initialization status of each kernel and any errors.

Live Demo (StackBlitz)​

You can explore and interact with a live example of this setup on StackBlitz:

Bitbybit Platform

StackBlitz - Bitbybit & ThreeJS - All Kernels Setup

Key Takeaways​

  • Vite Simplifies Setup: Vite handles worker bundling and module resolution effectively.
  • KernelOptions for Control: You have fine-grained control over which geometry kernels are loaded, allowing you to tailor the application to specific needs and optimize performance.
  • Asynchronous Operations: Most Bitbybit operations are async because they communicate with Web Workers.
  • Inputs DTOs: Use these typed objects to configure geometry operations.
  • Separate Worker Files: Each kernel runs in its own dedicated worker.
  • Modular Design: The @bitbybit-dev/threejs package neatly integrates these complex components for use with ThreeJS.

This setup provides a robust foundation for building sophisticated 3D CAD applications in the browser with Bitbybit and ThreeJS.