Pascal Editor

A 3D building editor built with React Three Fiber and WebGPU.

https://github.com/user-attachments/assets/8b50e7cf-cebe-4579-9cf3-8786b35f7b6b

Run the Editor Locally

Node.js 22.13 or newer can create a persistent local Pascal installation without cloning this repository:

npx @pascal-app/cli editor

The CLI starts the editor and an authenticated MCP service in the background, selects collision-free loopback ports, and keeps projects in ~/.pascal/data/pascal.db. Configure an agent to launch pascal mcp connect. See Run Pascal locally for pnpm/Bun commands, project management, MCP setup, updates, storage paths, and troubleshooting.

Agent skills

Install Pascal's public agent workflows from this repository with skills.sh:

npx skills add pascalorg/editor \
  --skill pascal-3d \
  --skill furniture-fit

Claude Code users can install the same canonical skill source as a plugin:

/plugin marketplace add pascalorg/editor
/plugin install pascal-agent-skills@pascal

Codex users can install the same plugin from the repository marketplace:

codex plugin marketplace add pascalorg/editor
codex plugin add pascal-agent-skills@pascal

pascal-3d covers safe local or hosted MCP setup and verified scene work. furniture-fit produces a bounded, evidence-based footprint assessment without claiming unsupported height, swing, or delivery checks. See skills/README.md for package details and validation.

The skills inspect the connected MCP tool schemas before using optional fields. A capability present in this repository may be absent from an older installed or hosted release; the agent should report the narrower supported result instead of assuming source-only inputs are available.

Using Published Packages

The viewer runtime and built-in node definitions are separate packages. Install the full built-in viewer set, then load the built-in plugin once before mounting <Viewer>. Capture sessions are an optional transport-neutral extension:

npm install @pascal-app/core @pascal-app/viewer @pascal-app/editor @pascal-app/nodes
npm install @pascal-app/capture-protocol @pascal-app/capture-viewer

import { loadPlugin } from '@pascal-app/core'
import { builtinPlugin } from '@pascal-app/nodes'

await loadPlugin(builtinPlugin)

See the @pascal-app/viewer quick start for a React example.

Repository Architecture

This is a Turborepo monorepo with the reusable editor packages, the standalone app, and the CLI that distributes it:

editor/
├── apps/
│   └── editor/          # Next.js application
├── packages/
│   ├── core/            # Schemas, scene state, and registry contracts
│   ├── viewer/          # 3D rendering runtime and shared systems
│   ├── capture-protocol/ # Static/live capture-session contracts
│   ├── capture-viewer/  # Capture source runtime and reference renderers
│   ├── editor/          # Editing tools and UI components
│   ├── nodes/           # Built-in node definitions, renderers, and systems
│   ├── cli/             # Persistent local editor installer and process manager
│   ├── mcp/             # Model Context Protocol server and scene storage
│   └── ui/              # Shared UI components

Separation of Concerns

The viewer renders the scene with sensible defaults. The editor extends it with interactive tools, selection management, and editing capabilities.

Stores

Each package has its own Zustand store for managing state:

Access patterns:

// Subscribe to state changes (React component)
const nodes = useScene((state) => state.nodes)
const levelId = useViewer((state) => state.selection.levelId)
const activeTool = useEditor((state) => state.tool)

// Access state outside React (callbacks, systems)
const node = useScene.getState().nodes[id]
useViewer.getState().setSelection({ levelId: 'level_123' })

Core Concepts

Nodes

Nodes are the data primitives that describe the 3D scene. All nodes extend BaseNode:

BaseNode {
  id: string              // Auto-generated with type prefix (e.g., "wall_abc123")
  type: string            // Discriminator for type-safe handling
  parentId: string | null // Parent node reference
  visible: boolean
  camera?: Camera         // Optional saved camera position
  metadata?: JSON         // Arbitrary metadata (e.g., { isTransient: true })
}

Node Hierarchy:

Site
└── Building
    └── Level
        ├── Wall → Item (doors, windows)
        ├── Slab
        ├── Ceiling → Item (lights)
        ├── Roof
        ├── Zone
        ├── Scan (3D reference)
        └── Guide (2D reference)

Nodes are stored in a flat dictionary (Record<id, Node>), not a nested tree. Parent-child relationships are defined via parentId and children arrays.

Scene State (Zustand Store)

The scene is managed by a Zustand store in @pascal-app/core:

useScene.getState() = {
  nodes: Record<id, AnyNode>,  // All nodes
  rootNodeIds: string[],       // Top-level nodes (sites)
  dirtyNodes: Set<string>,     // Nodes pending system updates

  createNode(node, parentId),
  updateNode(id, updates),
  deleteNode(id),
}

Middleware:

• Persist - Saves to IndexedDB (excludes transient nodes)
• Temporal (Zundo) - Undo/redo with 50-step history

Scene Registry

The registry maps node IDs to their Three.js objects for fast lookup:

sceneRegistry = {
  nodes: Map<id, Object3D>,    // ID → 3D object
  byType: {
    wall: Set<id>,
    item: Set<id>,
    zone: Set<id>,
    // ...
  }
}

Renderers register their refs using the useRegistry hook:

const ref = useRef<Mesh>(null!)
useRegistry(node.id, 'wall', ref)

This allows systems to access 3D objects directly without traversing the scene graph.

Node Renderers

Renderers are React components that create Three.js objects for each node type:

SceneRenderer
└── NodeRenderer (dispatches by type)
    ├── BuildingRenderer
    ├── LevelRenderer
    ├── WallRenderer
    ├── SlabRenderer
    ├── ZoneRenderer
    ├── ItemRenderer
    └── ...

Pattern:

1. Renderer creates a placeholder mesh/group
2. Registers it with useRegistry
3. Systems update geometry based on node data

Example (simplified):

const WallRenderer = ({ node }) => {
  const ref = useRef<Mesh>(null!)
  useRegistry(node.id, 'wall', ref)

  return (
    <mesh ref={ref}>
      <boxGeometry args={[0, 0, 0]} />  {/* Replaced by WallSystem */}
      <meshStandardMaterial />
      {node.children.map(id => <NodeRenderer key={id} nodeId={id} />)}
    </mesh>
  )
}

Systems

Systems are React components that run in the render loop (useFrame) to update geometry and transforms. They process dirty nodes marked by the store.

Core Systems (in @pascal-app/core):

Viewer Systems (in @pascal-app/viewer):

Processing Pattern:

useFrame(() => {
  for (const id of dirtyNodes) {
    const obj = sceneRegistry.nodes.get(id)
    const node = useScene.getState().nodes[id]

    // Update geometry, transforms, etc.
    updateGeometry(obj, node)

    dirtyNodes.delete(id)
  }
})

Dirty Nodes

When a node changes, it's marked as dirty in useScene.getState().dirtyNodes. Systems check this set each frame and only recompute geometry for dirty nodes.

// Automatic: createNode, updateNode, deleteNode mark nodes dirty
useScene.getState().updateNode(wallId, { thickness: 0.2 })
// → wallId added to dirtyNodes
// → WallSystem regenerates geometry next frame
// → wallId removed from dirtyNodes

Manual marking:

useScene.getState().dirtyNodes.add(wallId)

Event Bus

Inter-component communication uses a typed event emitter (mitt):

// Node events
emitter.on('wall:click', (event) => { ... })
emitter.on('item:enter', (event) => { ... })
emitter.on('zone:context-menu', (event) => { ... })

// Grid events (background)
emitter.on('grid:click', (event) => { ... })

// Event payload
NodeEvent {
  node: AnyNode
  position: [x, y, z]
  localPosition: [x, y, z]
  normal?: [x, y, z]
  stopPropagation: () => void
}

Spatial Grid Manager

Handles collision detection and placement validation:

spatialGridManager.canPlaceOnFloor(levelId, position, dimensions, rotation)
spatialGridManager.canPlaceOnWall(wallId, t, height, dimensions)
spatialGridManager.getSlabElevationAt(levelId, x, z)

Used by item placement tools to validate positions and calculate slab elevations.

Editor Architecture

The editor extends the viewer with:

Tools

Tools are activated via the toolbar and handle user input for specific operations:

• SelectTool - Selection and manipulation
• WallTool - Draw walls
• ZoneTool - Create zones
• ItemTool - Place furniture/fixtures
• SlabTool - Create floor slabs

Selection Manager

The editor uses a custom selection manager with hierarchical navigation:

Site → Building → Level → Zone → Items

Each depth level has its own selection strategy for hover/click behavior.

Editor-Specific Systems

• ZoneSystem - Controls zone visibility based on level mode
• Custom camera controls with node focusing

Data Flow

User Action (click, drag)
       ↓
Tool Handler
       ↓
useScene.createNode() / updateNode()
       ↓
Node added/updated in store
Node marked dirty
       ↓
React re-renders NodeRenderer
useRegistry() registers 3D object
       ↓
System detects dirty node (useFrame)
Updates geometry via sceneRegistry
Clears dirty flag

Building a Plugin

The editor is extensible: a plugin ships node kinds (schema, 3D/2D rendering, placement tools, inspector parametrics) and left-rail panels through the same Plugin manifest the built-ins use — there is no separate internal API.

• Developer guide — Create a plugin: the Plugin shape, panel contributions, discovery, lifecycle, and what's in/out of v1.
• Worked example — pascalorg/plugin-trees: a standalone plugin with procedural trees, flowers, grass, and a presets panel. Clone it as a starting point.

Technology Stack

• React 19 + Next.js 16
• Three.js (WebGPU renderer)
• React Three Fiber + Drei
• Zustand (state management)
• Zod (schema validation)
• Zundo (undo/redo)
• three-bvh-csg (Boolean geometry operations)
• Turborepo (monorepo management)
• Bun (package manager)

Getting Started

Development

Run the development server from the root directory to enable hot reload for all packages:

# Install dependencies
bun install

# Run development server (builds packages + starts editor with watch mode)
bun dev

# This will:
# 1. Build @pascal-app/core and @pascal-app/viewer
# 2. Start watching both packages for changes
# 3. Start the Next.js editor dev server
# Open http://localhost:3002

Important: Always run bun dev from the root directory to ensure the package watchers are running. This enables hot reload when you edit files in packages/core/src/ or packages/viewer/src/.

Building for Production

# Build all packages
turbo build

# Build specific package
turbo build --filter=@pascal-app/core

Publishing Packages

# Build packages
turbo build --filter=@pascal-app/core --filter=@pascal-app/viewer

# Publish to npm
npm publish --workspace=@pascal-app/core --access public
npm publish --workspace=@pascal-app/viewer --access public

Key Files

Contributing

Bug fixes, features, docs and ideas are all welcome. Start with CONTRIBUTING.md for setup, code style and the PR flow.

• New node kinds and sidebar panels ship as plugins rather than edits to the built-ins — pascalorg/plugin-trees is a worked example
• Questions and ideas go to Discussions; reproducible bugs go to Issues
• Participation is covered by our Code of Conduct
• Security problems go to SECURITY.md, not a public issue

Contributors