# Project Plan: 4D BIM Ông Đèn Box Culvert Simulation & Site Diary

## Overview
Transform the 3D BIM Box Culvert model into a full 4D BIM simulation and interactive site diary platform per ORIGINAL_REQUEST.md.

## Phase 0: Survey & Architecture Analysis
- Spawn 3 parallel Explorers:
  - Explorer 1 (3D BIM & Geometry): Investigate Three.js/WebGL scene, box culvert geometry, layers, dimension callouts/billboard sprites.
  - Explorer 2 (4D Timeline & Site Diary): Investigate state management, timeline playback, 6-phase sequence (Sheet 04), collapsible bottom dock.
  - Explorer 3 (Video Export & Test Harness): Investigate Canvas MediaRecorder, video rendering, backend routes, pytest and E2E browser test runners.
- Synthesize findings into `PROJECT.md` (Architecture, Feature Inventory, Milestones, Interface Contracts, Code Layout).

## Phase 1: Dual Track Decomposition & Setup
- Track 1: Implementation Track (Milestone Sub-Orchestrators):
  - M1: 3D Dimension Lines & Annotations (R1)
  - M2: 4D BIM Simulation & Lifetime Player (R2)
  - M3: Interactive Site Diary Dock (R3)
  - M4: Lifetime Video Export API & UI (R4)
  - M5: Final Integration & Full E2E Verification
- Track 2: E2E Testing Track:
  - Test Infra & Runner
  - Tier 1-4 Test Suites
  - Publish `TEST_READY.md`

## Phase 2: Milestone Execution & Verification Loop
- For each milestone: Explorer -> Worker -> Reviewers (2) -> Challengers (2) -> Forensic Auditor -> Gate.
- Regression & Oscillation guards enforced.

## Phase 3: Final Acceptance & Browser Verification
- Pass 100% of E2E test suite.
- Chrome DevTools automated browser verification (0 console errors, > 30 FPS).
- Human Reporter synthesis and handoff to parent.