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Using Bitbybit with BabylonJS

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

The @bitbybit-dev/babylonjs package conveniently includes @babylonjs/core 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 BabylonJS.

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-babylonjs-app -- --template vanilla-ts
# or: yarn create vite my-bitbybit-babylonjs-app --template vanilla-ts

cd my-bitbybit-babylonjs-app

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

npm install @bitbybit-dev/babylonjs
# or: yarn add @bitbybit-dev/babylonjs
Why these packages?
  • @bitbybit-dev/babylonjs: The main library for integrating Bitbybit with BabylonJS. It also installs these main packages listed below.
  • @babylonjs/core: Provides the main 3D engine to be used with this demo.
  • @bitbybit-dev/core: Collects all kernel web worker libraries into a 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 the OCCT worker and contains the main logic of the OCCT geometry kernel. It can also be used in non-web-worker environments.
  • @bitbybit-dev/jscad: Communicates with the JSCAD worker and contains the main logic of the JSCAD geometry kernel. It can also be used in non-web-worker environments.
  • @bitbybit-dev/manifold: Communicates with the Manifold worker and contains the main logic of the Manifold geometry kernel. It can also 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, usable across all kernels.

2. HTML Structure​

Modify your index.html file in the project root to include a <canvas> element where the BabylonJS 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 & BabylonJS Example</title>
  </head>
  <body>
      <canvas id="babylon-canvas"></canvas>
      <script type="module" src="/src/main.ts"></script>
  </body>
</html>

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

  • <canvas id="babylon-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/babylonjs';
import { OccStateEnum } from '@bitbybit-dev/occt-worker';
import { JscadStateEnum } from '@bitbybit-dev/jscad-worker';
import { ManifoldStateEnum } from '@bitbybit-dev/manifold-worker';

import {
  Engine,
  Scene,
  ArcRotateCamera,
  Vector3,
  HemisphericLight,
  Color4, // Using Color4 for scene clearColor for alpha
} from '@babylonjs/core';
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 BabylonJS scene
  const { scene, engine } = initBabylonJS();

  // Create an instance of BitByBitBase for BabylonJS
  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
  }

  // Start the BabylonJS render loop
  engine.runRenderLoop(() => {
      if (scene.activeCamera) { // Ensure camera is ready
          scene.render();
      }
  });
}

// --- 4. BabylonJS Scene Initialization ---
function initBabylonJS() {
  const canvas = document.getElementById('babylon-canvas') as HTMLCanvasElement;
  const engine = new Engine(canvas, true, {
      preserveDrawingBuffer: true,
      stencil: true,
  });
  const scene = new Scene(engine);
  scene.metadata = { shadowGenerators: [] }; // Important for Bitbybit till we have better implementation...
  scene.clearColor = new Color4(0.1, 0.11, 0.12, 1); // Set background color

  const camera = new ArcRotateCamera(
      'camera',
      -Math.PI / 2,
      Math.PI / 2.5,
      150, // Adjusted radius for typical scenes
      new Vector3(0, 0, 0),
      scene
  );
  camera.attachControl(canvas, true);
  camera.wheelPrecision = 50; // Control zoom speed
  camera.lowerRadiusLimit = 10;
  camera.upperRadiusLimit = 500;


  const light = new HemisphericLight('light', new Vector3(0, 1, 0), scene);
  light.intensity = 0.7;

  const onWindowResize = () => {
      engine.resize();
  };
  window.addEventListener('resize', onWindowResize, false);

  return { scene, engine, camera };
}

// --- 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) ---
// These functions demonstrate using Bitbybit's core geometry API.
// You use Inputs DTOs to define geometry parameters.
// bitbybit.draw.drawAnyAsync() from @bitbybit-dev/babylonjs handles rendering into the BabylonJS scene.

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; // Bitbybit handles color conversion
  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
  );

  const sphereOptions = new Inputs.JSCAD.SphereDto();
  sphereOptions.radius = 10;
  sphereOptions.center = [5, 45, 0];
  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/babylonjs. 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 BabylonJS modules for scene setup: Engine, Scene, ArcRotateCamera, Vector3, HemisphericLight, Color4.
    • 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 initBabylonJS() to set up the basic BabylonJS Engine, Scene, Camera, and Light.
    • Creates an instance of BitByBitBase from the @bitbybit-dev/babylonjs package.
    • 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, passing the BabylonJS scene.
    • Conditionally calls geometry creation functions (createOCCTGeometry, createManifoldGeometry, createJSCADGeometry) based on which kernels were enabled and successfully initialized.
    • Starts the BabylonJS render loop using engine.runRenderLoop(...).

  4. initBabylonJS() function:

    • Standard BabylonJS boilerplate: sets up the Engine attached to the canvas.
    • Creates a Scene and sets its clear color (background).
    • Creates an ArcRotateCamera for user interaction and attaches its controls to the canvas.
    • Adds a HemisphericLight to illuminate the scene.
    • Includes a window resize listener to ensure the engine adapts to viewport changes.

  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). The @bitbybit-dev/babylonjs package's BitByBitBase is designed to work with a BabylonJS Scene object and 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 illustrating how to use Bitbybit's core geometry API (e.g., bitbybit.occt.*, bitbybit.manifold.*, bitbybit.jscad.*).
    • 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.
    • Drawing: After creating a geometric entity, bitbybit.draw.drawAnyAsync() (from @bitbybit-dev/babylonjs) is used to render it into the BabylonJS scene. Different kernels might have slightly different drawing option DTOs (e.g., DrawOcctShapeOptions, DrawManifoldOrCrossSectionOptions, DrawBasicGeometryOptions), but drawAnyAsync handles many common cases.

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; /* Match canvas background for seamless look */
}

#babylon-canvas {
  display: block;
  width: 100vw;
  height: 100vh;
  touch-action: none; /* Recommended for BabylonJS pointer events */
}

6. Running the Application​

npm run dev
# or: yarn dev

Vite will start a development server. You should see a browser window open with your BabylonJS 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 & BabylonJS - All Kernels Setup

Key Takeaways​

  • Vite Simplifies Setup: Vite handles worker bundling and module resolution effectively for a smooth development experience.
  • 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, ensuring the main thread remains responsive.
  • Inputs DTOs: Use these typed objects to configure geometry operations, promoting code clarity and type safety.
  • Separate Worker Files: Each geometry kernel runs in its own dedicated worker, maximizing performance for computationally intensive tasks.
  • Modular Design: The @bitbybit-dev/babylonjs package seamlessly integrates Bitbybit's powerful geometry kernels and functionalities with your BabylonJS applications.

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