LumixEngine

3D UI

UI supports rendering UI documents as world-space 3D surfaces.

Overview

There are two UI rendering paths:

• World-level UI document (existing behavior): rendered in GAME_VIEW.
• 3D UI component (UI3D): rendered in both GAME_VIEW and SCENE_VIEW.

3D UI is currently render-only (no pointer/raycast interaction).

Adding 3D UI to an entity

1. Select an entity in the world.
2. Add the UI / UI3D component.
3. Set these properties:
   • Source: path to a .ui document.
   • Virtual size: logical canvas size (for example 1000, 1000).
   • Orient to camera: if enabled, the surface faces the active camera.

If Source is empty, the component is inactive and renders nothing.

Property behavior

• Source
  • Loads a .ui document resource for this entity.
  • Changing the value reloads the document for that component.
• Virtual size
  • Controls the document layout space before projection into world space.
  • Larger values give more UI pixels; world transform still controls final world-space scale.
• Orient to camera
  • true: billboard-like orientation toward the camera while keeping entity position/scale.
  • false: uses the entity transform orientation directly.

Notes and limitations

• 3D UI does not consume UI input events yet.
• The world-level <world>.ui flow remains unchanged and works alongside UI3D components.
• Save/load persists UI3D properties (Source, Virtual size, Orient to camera).

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