dcl-regenesislabs/create-scene

Create a New Decentraland SDK7 Scene

Runtime constraint: Decentraland runs in a QuickJS sandbox. No Node.js APIs (fs, http, path, process). Use the SDK's executeTask() + fetch() for async work. See the scene-runtime skill for details.

When the user wants to create a new scene, follow these steps:

1. Ask What They Want to Build

If the user hasn't described their scene, ask them:

• What kind of scene? (gallery, game, social space, interactive art, etc.)
• How many parcels? (default: 1 parcel = 16x16m)
• Any specific features? (3D models, interactivity, UI, multiplayer)

2. Scaffold the Project with /init

Always run /init first. This uses the official @dcl/sdk-commands init to create scene.json, package.json, tsconfig.json, and src/index.ts with the correct, up-to-date configuration, and installs dependencies automatically.

Never manually create scene.json, package.json, or tsconfig.json — the SDK templates may change between versions and hand-written copies will diverge.

3. Find Matching 3D Assets

Before writing scene code, search the asset catalog for free models that match the user's theme:

1. Search the model catalog (5,700+ optimized 3D models — characters, structures, props, nature, vehicles, etc.)

   grep -i "keyword" {baseDir}/../add-3d-models/references/model-catalog.md
   

2. Read {baseDir}/../../context/audio-catalog.md (50 free sounds — music, ambient, SFX, game mechanics, etc.)
3. Fetch the preview thumbnail (the preview: URL at the end of each catalog line) to visually confirm models
4. Suggest matching models and sounds to the user
5. Download selected models into the scene's models/ directory:

   mkdir -p models
   curl -o models/zombie-purple.glb "https://models.dclregenesislabs.xyz/blobs/bafybeiffc..."
   

Important: GltfContainer only works with local files. Never use external URLs for the model src field.

4. Customize the Generated Files

After /init completes, customize the generated files based on what the user wants:

scene.json

Update the display fields and parcels:

• display.title — set to the scene name
• display.description — set to a short description
• scene.parcels — for multi-parcel scenes, list all parcels (e.g., ["0,0", "0,1", "1,0", "1,1"] for 2x2)
• scene.base — set to the southwest corner parcel

main-entities.ts + src/index.ts

OpenDCL scenes use a two-file authoring model:

• main-entities.ts (scene root) — typed declarative entities + their data components, keyed by Name. Compiled to main.crdt at build time and preloaded by the engine before main() runs.
• src/index.ts — behavior only. References entities by Name via engine.getEntityOrNullByName<EntityName>(name) and attaches systems, pointer events, tweens, etc.

Example main-entities.ts:

import type { Scene } from '@dcl/sdk/scene-types'

export const scene = {
  blue_cube: {
    components: {
      Transform: { position: { x: 8, y: 1, z: 8 }, rotation: { x: 0, y: 0, z: 0, w: 1 }, scale: { x: 1, y: 1, z: 1 } },
      MeshRenderer: { mesh: { $case: 'box', box: { uvs: [] } } },
      Material: {
        material: { $case: 'pbr', pbr: { albedoColor: { r: 0.2, g: 0.5, b: 1, a: 1 } } },
      },
    },
  },
} satisfies Scene

The satisfies Scene clause keeps the literal keys typed (so keyof typeof scene gives the typed entity-name union), while still validating the shape against the Scene schema.

Example src/index.ts:

import { engine, pointerEventsSystem, InputAction } from '@dcl/sdk/ecs'
import type { scene } from '../main-entities'

type EntityName = keyof typeof scene

export function main() {
  const cube = engine.getEntityOrNullByName<EntityName>('blue_cube')
  if (cube === null) return

  pointerEventsSystem.onPointerDown(
    { entity: cube, opts: { button: InputAction.IA_POINTER, hoverText: 'Click me' } },
    () => console.log('clicked'),
  )
}

tsconfig.json should include main-entities.ts so it gets type-checked:

{
  "extends": "@dcl/sdk/types/tsconfig.ecs7.json",
  "include": ["src/**/*.ts", "src/**/*.tsx", "main-entities.ts"]
}

Rules:

• Every editable / declared entity must have a unique Name in main-entities.ts.
• Dynamic entities created at runtime (effects, projectiles, dynamic UI markers) use engine.addEntity() directly. Don't give dynamic entities a Name — they don't go in main-entities.ts.
• Anything that's pure data (Transform, GltfContainer, MeshRenderer, MeshCollider, Material, AudioSource, VideoPlayer, TextShape, Animator config, NftShape, Billboard, VisibilityComponent) goes in main-entities.ts.
• Anything that's behavior (pointer callbacks, systems, tween triggers, conditional logic) goes in src/.
• The scene literal must be JSON-compatible — no function calls, no spreads, no comments inside the object.

scene.json Reference

All valid scene.json fields:

| Field | Required | Description | |-------|----------|-------------| | ecs7 | Yes | Must be true for SDK7 | | runtimeVersion | Yes | Must be "7" | | main | Yes | Must be "bin/index.js" — the compiled output path | | display.title | Recommended | Scene name shown in the map and Places | | display.description | Recommended | Short description for discovery | | display.navmapThumbnail | Optional | Image path for the Genesis City minimap | | scene.parcels | Yes | Array of "x,y" coordinate strings | | scene.base | Yes | The origin parcel (usually southwest corner) | | spawnPoints | Optional | Where players appear when entering (see below) | | requiredPermissions | Optional | Array of permissions (e.g., "ALLOW_MEDIA_HOSTNAMES") | | allowedMediaHostnames | Optional | Whitelisted domains for external media | | featureToggles | Optional | Enable/disable SDK features | | worldConfiguration | Optional | For Worlds deployment (see deploy-worlds skill) | | authoritativeMultiplayer | Optional | Enable authoritative server mode (see authoritative-server skill) |

Spawn Points

Configure where and how players enter the scene:

{
  "spawnPoints": [
    {
      "name": "spawn1",
      "default": true,
      "position": { "x": [1, 5], "y": [0, 0], "z": [2, 4] },
      "cameraTarget": { "x": 8, "y": 1, "z": 8 }
    }
  ]
}

• Position ranges (e.g., [1, 5]) spawn players randomly within the range
• cameraTarget orients the player's camera on spawn — point it at the scene's focal area
• Fixed spawn: use single values instead of ranges (e.g., "x": 8)

Multi-Parcel Layouts

| Layout | Parcels Array | Use Case | |--------|--------------|----------| | Single | ["0,0"] | Small games, galleries, single-room experiences | | Strip | ["0,0", "1,0", "2,0"] | Hallways, racing tracks, linear journeys | | L-Shape | ["0,0", "1,0", "0,1"] | Corner buildings, split experiences | | 2x2 Square | ["0,0", "1,0", "0,1", "1,1"] | Open plazas, arenas, medium games | | 3x3 Square | 9 parcels from "0,0" to "2,2" | Large games, multi-room buildings |

Base parcel: Always set scene.base to the southwest (lowest x,y) corner parcel.

Boundaries per parcel: 16m x 16m x 20m height. A 2x2 scene spans 32m x 32m.

5. Post-Creation Steps

After customizing the files:

1. Use the preview tool to start the preview server (or run npx @dcl/sdk-commands start --bevy-web manually)
2. The scene will open in a browser at http://localhost:8000

Cross-References

• Ready to deploy? See the deploy-scene skill (Genesis City) or deploy-worlds skill (personal Worlds)
• Need to optimize for parcel limits? See the optimize-scene skill
• Planning a game? See the game-design skill for design patterns and performance budgets

Important Notes

• Always place objects within the scene boundaries (0 to 16parcelsX for X, 0 to 16parcelsZ for Z)
• Center of a single-parcel scene is (8, 0, 8) at ground level
• Y axis is up, minimum Y=0 (ground)
• The main field in scene.json MUST be "bin/index.js" — this is the compiled output path
• The jsx and jsxImportSource tsconfig settings are already included by /init — do not modify them
• Never pass undefined values in Transform fields (position, rotation, scale) — the SDK serializer crashes. If a field is optional, omit the key entirely instead of including it with an undefined value.