An open-source 3D building editor is surging on GitHub, attracting 171 stars in a single day as architects and developers take notice of its WebGPU-powered approach to collaborative architectural design.
What Is Pascal Editor?
Pascal Editor is a browser-based 3D building editor built with React Three Fiber and WebGPU, designed for creating and sharing architectural projects directly in the browser. The project is published under the MIT license and is organized as a Turborepo monorepo with a clean package separation.
The core architecture splits into focused packages:
- @pascal-app/core — Node schemas, scene state (Zustand), registry contracts, spatial queries, and an event bus - @pascal-app/viewer — 3D rendering via React Three Fiber, shared render systems, and default camera/controls - @pascal-app/editor — Editing tools, panels, selection, and direct-manipulation UI - @pascal-app/nodes — Built-in node definitions, renderers, geometry, and systems - @pascal-app/cli — Persistent local editor installer and process manager - @pascal-app/mcp — Model Context Protocol server for AI agent integration
Key Technical Highlights
Node-based scene graph: All 3D objects are described as nodes in a flat dictionary with parent-child relationships. The hierarchy flows from Site to Building to Level to Wall/Slab/Ceiling/Roof, with items like doors and windows as children of walls.
WebGPU rendering: The project uses Three.js with the WebGPU renderer, taking advantage of the modern GPU API for performance-critical 3D operations.
Dirty-node system: Rather than re-rendering the entire scene on every change, Pascal uses a dirty-node tracking system. When a node is modified, it's marked dirty, and systems process only dirty nodes on the next frame — a pattern common in game engines but less common in web-based CAD tools.
MCP integration: The `@pascal-app/mcp` package exposes scene tools, resources, and local storage to MCP-compatible AI hosts, allowing AI agents to interact with and modify 3D scenes programmatically.
Plugin architecture: The editor is extensible through plugins that ship new node kinds, 3D/2D rendering, placement tools, and sidebar panels using the same manifest as built-in components. An example plugin for procedural trees, flowers, and grass is available as a template.
Getting Started
The fastest way to try Pascal is:
``` npx @pascal-app/cli editor ```
This creates a persistent local installation, selects collision-free loopback ports, and stores projects in `~/.pascal/data/pascal.db`. The CLI also starts an authenticated MCP service in the background for AI agent connectivity.
For development, the project uses Bun as its package manager and supports hot reload across all packages:
``` bun install && bun dev ```
Technology Stack
The project is built on a modern web stack: React 19, Next.js 16, Three.js (WebGPU), React Three Fiber with Drei, Zustand for state management, Zod for schema validation, Zundo for undo/redo, three-bvh-csg for Boolean geometry operations, and Turborepo for monorepo management.
Why It Matters
Web-based 3D CAD tools have historically struggled with performance and extensibility. Pascal Editor's combination of WebGPU rendering, a game-engine-inspired dirty-node system, and a clean plugin architecture positions it as a serious contender for browser-native architectural design. The MCP integration for AI agents is a notable addition, suggesting the project is betting on AI-assisted design workflows as a core use case.
The project was created by Pascal (pascalorg) and is trending on GitHub as of September 9, 2026.
