diff --git a/SETUP.md b/SETUP.md
index 53589ce..96154db 100644
--- a/SETUP.md
+++ b/SETUP.md
@@ -1,63 +1,110 @@
 # G1 Teleop — Quest 3 Native App Setup
 
+## Overview
+
+Godot 4.6.1 Quest 3 VR app for teleoperating a Unitree G1 humanoid robot. Uses OpenXR with Meta Quest hand tracking, body tracking, and passthrough.
+
 ## Prerequisites
 
-- **Godot 4.3+** (download from https://godotengine.org)
-- **Android SDK + NDK** (install via Android Studio or standalone)
-- **Meta Quest Developer Hub** (for sideloading) or `adb`
+- **Godot 4.6.1** — located at `Godot4_6_1/Godot_v4.6.1-stable_win64_console.exe`
+- **Android SDK + NDK** — located at `android-sdk/`
+- **JDK 17** — located at `jdk17/`
+- **OpenXR Vendors plugin v4.3.0** — located at `addons/godotopenxrvendors/`
+- **adb** — located at `C:\Users\John\Downloads\platform-tools\adb.exe`
 - Quest 3 in **developer mode**
 
-## Step 1: Install Meta OpenXR Vendors Plugin
+## Build Pipeline
 
-1. Open project in Godot: `godot --editor --path C:\git\g1-teleop`
-2. Go to **AssetLib** tab (top center)
-3. Search for "Godot OpenXR Vendors"
-4. Download and install (includes Meta Quest support)
-5. Enable the plugin: **Project → Project Settings → Plugins → godotopenxrvendors** → Enable
-6. Restart Godot when prompted
-
-## Step 2: Configure Android Export
+```bash
+# 1. Setup vendor plugin (copies AARs and .so files)
+python build/setup_vendor_plugin.py
 
-1. Go to **Editor → Editor Settings → Export → Android**
-2. Set the path to your Android SDK
-3. Set Java SDK path
-4. Go to **Project → Export → Quest 3**
-5. Download Android export templates if prompted (Editor → Manage Export Templates → Download)
+# 2. Build APK (headless Godot export)
+build\build_461.bat
 
-## Step 3: Enable Body Tracking
+# 3. Install to Quest 3
+adb install -r build/g1-teleop.apk
+```
 
-Body tracking is configured via:
-- `export_presets.cfg`: `xr_features/hand_tracking=2` (required)
-- `android/AndroidManifest.xml`: body tracking features and metadata
+The build script runs: `Godot_v4.6.1-stable_win64_console.exe --headless --quit --path . --export-debug "Quest 3" build/g1-teleop.apk`
 
-The Meta OpenXR Vendors plugin v4.1.1+ exposes `XRBodyTracker` in GDScript.
+## Architecture
 
-## Step 4: Build and Sideload
+### Two-Phase Startup
+- **CONFIG phase**: Dark VR environment with start screen UI, G1 robot models spinning on each side, hand laser pointer with pinch-to-click for menu interaction
+- **AR phase**: Meta Quest passthrough with body tracking, webcam quad, gaze-activated exit balls
 
-1. Connect Quest 3 via USB (or Wi-Fi ADB)
-2. In Godot: **Project → Export → Quest 3 → Export Project** (or one-click deploy)
-3. APK will be at `build/g1-teleop.apk`
-4. Sideload: `adb install build/g1-teleop.apk`
+### Key Files
 
-## Step 5: Robot Server
+| File | Purpose |
+|------|---------|
+| `Main.gd` | Main controller — phase management, passthrough, gaze balls, G1 models, recenter |
+| `Main.tscn` | Scene tree — XROrigin3D, camera, controllers, start screen, webcam quad |
+| `scripts/vr_ui_pointer.gd` | Hand laser pointer, pinch-to-click, hand poke, controller ray interaction |
+| `scripts/body_tracker.gd` | XRBodyTracker joint visualization and tracking data |
+| `scripts/teleop_client.gd` | WebSocket client for robot communication |
+| `scripts/start_screen.gd` | Config UI panel (connect, launch AR buttons) |
+| `scripts/webcam_quad.gd` | Webcam video display |
+| `project.godot` | Project settings including OpenXR extensions |
+| `export_presets.cfg` | Android export config with Meta XR features |
+| `models/g1_full.obj` | 3D model of G1 robot (76MB OBJ, Z-up) |
 
-On the robot (or dev machine for testing):
+### Critical Project Settings (`project.godot`)
 
-```bash
-cd server/
-pip install -r requirements.txt
-python teleop_server.py --port 8765
+```ini
+openxr/extensions/meta/passthrough=true    # Required for Quest passthrough
+openxr/extensions/meta/body_tracking=true  # Required for body tracking
+openxr/environment_blend_mode=0            # Must stay 0, passthrough enabled via code
 ```
 
-## Step 6: Configure App
+### Critical Export Settings (`export_presets.cfg`)
 
-Edit `scripts/teleop_client.gd` to set the robot's IP:
-```gdscript
-@export var server_host: String = "10.0.0.64"  # Robot IP
-@export var server_port: int = 8765
+```ini
+meta_xr_features/hand_tracking=2
+meta_xr_features/passthrough=2
+meta_xr_features/body_tracking=2
 ```
 
-Or configure at runtime via the Godot editor's export properties.
+## Technical Notes
+
+### Meta Quest Passthrough
+- Requires `openxr/extensions/meta/passthrough=true` in project.godot AND `meta_xr_features/passthrough=2` in export presets
+- `get_supported_environment_blend_modes()` only returns `[0]` (opaque) on Quest — must force `set_environment_blend_mode(XR_ENV_BLEND_MODE_ALPHA_BLEND)` without checking support
+- The Meta vendor plugin intercepts this call via `XR_FB_PASSTHROUGH` extension
+- Also requires `transparent_bg = true` on the viewport and `clear_color = Color(0,0,0,0)`
+- Do NOT add a WorldEnvironment with BG_COLOR black — it makes everything black in VR
+
+### Hand Tracking
+- Palm joint's `-basis.z` points perpendicular to palm (upward when hand flat), NOT forward
+- Ray direction must be computed geometrically: wrist to middle finger metacarpal
+- XRHandTracker joints: PALM=0, WRIST=1, THUMB_TIP=5, INDEX_TIP=10, MIDDLE_META=11
+- Pinch detection: thumb tip to index tip distance with hysteresis (press <2.5cm, release >3.5cm)
+
+### Scene Parenting
+- Nodes under `XRCamera3D` follow head tracking
+- Nodes under `XROrigin3D` stay stationary in tracking space
+- Webcam quad is under `XROrigin3D` (stationary), not `XRCamera3D`
+
+### OBJ Model Loading
+- `load("res://models/g1_full.obj")` returns a `Mesh` resource directly (not PackedScene)
+- OBJ files use Z-up; Godot uses Y-up — rotate -90 degrees on X axis to stand upright
+- G1 model scale: `Vector3(0.0015, 0.0015, 0.0015)`
+- Needs explicit material override and a DirectionalLight3D for shading
+
+### GDScript Gotchas
+- Untyped Arrays return Variant — use explicit type: `var ball: MeshInstance3D = _gaze_balls[i]`
+- Cannot infer types from Variant expressions — annotate variables explicitly
+
+### Gaze Ball System
+- 4 balls above field of view: red (exit AR), yellow (reserved), green (reserved), blue (quit app)
+- Head gaze detection via angle threshold (8 degrees)
+- 5-second stare to activate with visual feedback (opacity, color, scale 1.0x to 1.8x)
+- Laser beam from head to gazed ball
+
+### Recenter Support
+- Connected to `XRInterface.pose_recentered` signal
+- Must connect in both `is_initialized()` and `elif` branches of `_ready()`
+- Repositions start screen + G1 models (CONFIG) or webcam + gaze balls (AR)
 
 ## Network
 
@@ -77,3 +124,10 @@ Or configure at runtime via the Godot editor's export properties.
 - Verify robot IP is correct and reachable: `ping 10.0.0.64`
 - Check server is running: `ss -tlnp | grep 8765`
 - Check firewall: `sudo ufw allow 8765/tcp`
+
+### Passthrough shows black/gray
+- Verify `openxr/extensions/meta/passthrough=true` in project.godot
+- Verify `meta_xr_features/passthrough=2` in export_presets.cfg
+- Do NOT set `openxr/environment_blend_mode=2` in project.godot (keep it 0)
+- Force alpha blend mode via code, not project settings
+- Remove any WorldEnvironment node with black background