# ADR 0011: Scene lighting policy (project sun vs scene sun)

## Status

Accepted

## Context

A single scene-authored directional `LightDesc` hides the runtime `ProjectSun`, which can make outdoor levels appear black if lux values are wrong. Project Settings ambient/sun did not always apply live after **Apply**.

## Decision

- **`ProjectSun`** is the default outdoor directional; scene-authored directionals override it (existing `sync_project_sun_visibility` behavior).
- **Editor commands** (Scene menu + Rendering Diagnostics): *Use project sun* (remove scene directionals) and *Bake scene sun from project* (spawn directional `LightDesc` from current `sun_illuminance`).
- On **`ProjectSettingsChanged`**, the editor applies ambient light, `sync_project_sun_illuminance`, and `sync_project_sun_visibility`; render view refreshes via existing `ProjectSettings` change detection.
- Legacy directional lux < 1000 is corrected in **schema migration** to `100_000` lux (documented default), not at hydration time.

## Consequences

- Status/diagnostics UI should surface sun override state (Rendering Diagnostics panel).
- Designers use authoring `LightDesc` units: lumens (point/spot), lux (directional).