WWDC Quick Look đź’“ By SwiftGGTeam
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Iterate your spatial scenes faster with Reality Composer Pro 3

Iterate your spatial scenes faster with Reality Composer Pro 3

Reality Composer ProvisionOSSpatial ComputingLightmapsAI Assistant
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Reality Composer Pro 3 changes from an Xcode development tool into a standalone app. It introduces three major capabilities, Live Preview, Lightmap baking, and AI Assistant, so developers can add content, visual effects, lighting, and interaction design inside the editor without writing code.

Core Ideas

From Xcode plugin to standalone editor

Reality Composer Pro used to be embedded in Xcode. It had a long launch path and was inconvenient for collaboration with people outside development tools. After WWDC26, it becomes a standalone app that you can download directly from developer.apple.com and run by double-clicking. (02:02)

The significance is that designers, artists, and planners can use the editor independently without waiting for developers to set up an Xcode project. Team responsibilities become clearer, and iteration gets faster.

Live Preview removes the guesswork

One of the most painful parts of building spatial content is this: effects that look right on a Mac screen can feel completely wrong after you put on Vision Pro. Lighting, particles, and physical interactions can look very different on a flat display and in a spatial device. (11:12)

Live Preview lets Reality Composer Pro on Mac connect directly to Vision Pro. Every adjustment in the editor syncs to the device in real time. Developers can tune parameters while seeing the result in real space. “What you see is what you get” is not a slogan here; it is the workflow.

Prototypes: change once, update everywhere

Scenes often need to reuse the same kind of object, such as multiple magic effects or multiple NPCs. The old approach was copy and paste, then manually update every copy after a change. (08:44)

Reality Composer Pro 3 introduces a Prototype system. Drag an entity into the Project Browser to turn it into a prototype asset, then drag it back into the scene to create an instance. Each instance can override properties independently, such as using a different Compute Graph or adjusting color intensity. If the change is wrong, right-click Reset to restore the prototype default. If you want to promote one instance’s changes to all copies, use Propagate.

This system essentially turns the idea of inheritance plus overrides into a drag-and-drop workflow.

Lightmaps: baking indirect lighting into textures

Indirect lighting is crucial for spatial scenes to look good. Light from a fireplace hits a wall and bounces under a table; that bounced light gives dark areas detail and depth. But real-time indirect lighting is expensive. (12:15)

The Lightmap component in Reality Composer Pro 3 can precompute indirect lighting and store the result as textures. The editor supports three bake modes:

  • Indirect Lighting: Bake only indirect light
  • Ambient Occlusion: Bake ambient occlusion, or how much each point is “seen” by its surroundings
  • Beauty: Bake final color, including direct and indirect light

Before baking, you can tune parameters and preview the result in real time in the Lightmap Preview tab. Once the result looks right, click Bake. This avoids waiting for full bakes over and over.

AI Assistant: generate 3D content with natural language

When a scene is missing a few props, the old workflow was to open Blender, model them, export USD, and import them into the project. Reality Composer Pro 3 adds AI Assistant in the right-side panel, letting you generate 3D objects and materials from natural language descriptions. (14:52)

In the demo, the presenter typed a prompt, and AI generated several bottles and jars for a workbench, then added a few candles. The whole process stayed inside the editor, with no tool switching.

Details

Entity and Component: the basic units of a scene

Scenes in Reality Composer Pro 3 are made of Entity and Component. An Entity is an object in the scene; a Component is a capability attached to that object. (03:47)

The Hierarchy panel shows all entities and supports drag-and-drop ordering and nesting. After you select an entity, the Inspector panel shows its components. Every entity has at least a Transform Component, which controls position, rotation, and scale.

Click Add Component to add:

  • Light
  • Physics
  • Audio
  • Compute Simulation
  • Lightmap

Compute Graph: node-based GPU programming

A Compute Simulation component can bind to a Compute Graph. This is the node-based GPU programming tool in Reality Composer Pro 3. You do not need to write Metal shaders; you can build particle systems, fluid simulation, and similar effects by dragging nodes. (06:33)

In the demo, the presenter added a Compute Simulation component to a “Magic Effect” entity and selected the preset Magic Graph in the Inspector. After clicking Play, the simulation tab showed the particle effect in real time. The scene tab could stay open next to it, letting the presenter adjust entity position and rotation while getting immediate feedback in both views.

Key points:

  • Compute Graph only runs during simulation, not during editing
  • The simulation tab and scene tab can be docked side by side so you can tune parameters while watching the effect
  • Everything from physics simulation to script graphs and animation supports live preview

The full Prototype workflow

To turn an entity into a prototype:

  1. Select the entity in the Hierarchy panel
  2. Drag it into the Project Browser to generate a prototype asset automatically
  3. Drag the prototype from Project Browser back into the Viewport to create an instance

Each instance appears as a prototype reference in the Hierarchy. Overridden properties are marked in the Inspector. You can right-click a property to:

  • Reset: Restore the prototype default value
  • Propagate to Source: Push this instance’s change back to the prototype, affecting all instances

Lightmap bake configuration

After adding a Lightmap component to an entity, you can adjust Bake Settings:

  • Quality: Low / Medium / High
  • Lighting Term: Indirect / Ambient Occlusion / Beauty

After tuning parameters, open the Lightmap Preview tab from the Tab menu to see the impact of indirect lighting on the scene in real time. Once the result is confirmed, click Bake. The editor computes in the background and applies the result automatically when finished. (13:11)

How Live Preview connects

  1. Make sure Vision Pro and Mac are on the same network
  2. Select the target device in the Launch Control panel
  3. Click Live Preview; Vision Pro opens the companion app automatically
  4. Edit on Mac and sync to Vision Pro in real time

In the demo, the presenter adjusted parameters for a blue fill light, and Vision Pro immediately showed the change in Physical Space Lighting. (11:34)

Key Takeaways

1. Use the Prototype system to manage repeated elements

When a scene has many reused objects, such as props, effects, or NPCs, manage them with Prototype. Change the prototype once and all instances update. Add overrides only when customization is needed. Entry point: drag an entity from the Hierarchy panel into Project Browser.

2. Tune lighting directly on Vision Pro

Lighting in spatial scenes is hard to judge on a flat display. Use Live Preview to sync the editor view to Vision Pro, then adjust light color, intensity, and position while seeing the spatial result directly. This is especially useful for features like Physical Space Lighting that depend on the real environment.

3. Use Lightmaps to optimize static scene performance

For areas where lights and geometry do not move, add a Lightmap component to prebake indirect lighting. Runtime no longer needs to compute it live, and frame rate becomes more stable. The Preview tab lets you tune parameters before Bake, avoiding repeated full computations.

4. Use AI Assistant to fill scene details quickly

When prototyping or building a demo, missing small props no longer require opening modeling software. Type a description in the right-side AI Assistant panel and generate 3D objects and materials directly. This is useful for quickly validating composition and atmosphere.

5. Let designers work independently and reduce development blockers

Now that Reality Composer Pro 3 is a standalone app, designers can build scenes, adjust lighting, and manage prototypes independently without waiting for developers to prepare an Xcode project. In early project stages, let designers get moving first, then have developers connect the code layer later.

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