Annotation Camera System

The annotation camera system provides interactive 3D navigation for character models, with clickable markers that focus the camera on specific body parts.

Architecture Overview

AnnotationCameraController (main orchestrator)
├── OrbitControls (mouse interaction)
├── AnnotationMarkers (HTML-based labels) OR Annotation3DMarkers (3D geometry)
├── CameraDOMControls (dropdown selector)
└── Annotations config (per-character presets)

Key Files

Annotation Interface

interface Annotation {
  name: string;              // Display name (snake_case recommended)
  bones?: string[];          // Bone names to focus on
  meshes?: string[];         // Mesh names to focus on
  objects?: string[];        // Any object names (use ['*'] for all)
  paddingFactor?: number;    // Zoom padding (1.0 = tight, 2.0 = loose)
  cameraAngle?: number;      // Y-axis rotation (0=front, 90=right, 180=back, 270=left)
  cameraOffset?: { x?, y?, z? }; // Fine-tune camera position
}

Adding a New Annotation

1. Open src/presets/annotations.ts
2. Find the character config (e.g., JONATHAN_ANNOTATIONS)
3. Add to the annotations array:

{
  name: 'left_shoulder',
  bones: ['CC_Base_L_Clavicle', 'CC_Base_L_Upperarm'],
  paddingFactor: 1.4,
  cameraAngle: 270,  // View from left side
}

3D Markers

All markers are pure 3D geometry (no HTML overlays):

• Sphere dots placed on mesh surface via raycasting
• 3D lines extending outward from the surface
• Sprite labels (canvas-rendered text billboards) at line endpoints
• Markers rotate with the model and have proper depth
• Click detection via 3D raycasting

Camera Focus Methods

// Focus on named annotation
controller.focusAnnotation('left_eye', 800);

// Focus on specific bones
controller.focusBones(['CC_Base_L_Hand'], 800);

// Focus on meshes
controller.focusMeshes(['CC_Base_Eye'], 800);

// Focus on full body
controller.focusFullBody(800);

Camera Angle Convention

Padding Factor Guidelines

CRITICAL: Skinned Mesh Positioning

Skinned meshes (eyes, teeth, tongue, etc.) have their geometry at world origin (0,0,0). The mesh is positioned by the skeleton bones at runtime.

Consequence for Annotations

• NEVER use meshes alone for skinned mesh parts - the marker will appear at model origin (usually the feet)
• NEVER mix meshes with bones if the meshes are skinned - the skinned mesh origin (0,0,0) will skew the center calculation
• ALWAYS use bones for accurate marker positioning on body parts controlled by skeleton

Examples

// WRONG - marker will appear at feet/origin
{
  name: 'left_eye',
  meshes: ['CC_Base_Eye'],  // BAD: skinned mesh at origin
  paddingFactor: 1.2,
}

// WRONG - mixing bones and skinned meshes skews center toward origin
{
  name: 'mouth',
  bones: ['CC_Base_JawRoot'],
  meshes: ['CC_Base_Teeth', 'CC_Base_Tongue'],  // BAD: these are at (0,0,0)
  paddingFactor: 1.5,
}

// CORRECT - marker appears at actual eye position
{
  name: 'left_eye',
  bones: ['CC_Base_L_Eye'],  // GOOD: bone has correct world position
  paddingFactor: 1.2,
}

// CORRECT - mouth uses only bones
{
  name: 'mouth',
  bones: ['CC_Base_JawRoot'],  // GOOD: bone only, no skinned meshes
  paddingFactor: 1.5,
}

CC4 Skinned Meshes to Avoid

• CC_Base_Eye, CC_Base_Eye_1 → Use CC_Base_L_Eye, CC_Base_R_Eye bones
• CC_Base_Teeth, CC_Base_Tongue → Use CC_Base_JawRoot bone

Bone Names by Character

CC4 Characters (Jonathan)

• Head: CC_Base_Head, CC_Base_JawRoot
• Eyes: CC_Base_L_Eye, CC_Base_R_Eye (use bones, NOT mesh names)
• Spine: CC_Base_Spine01, CC_Base_Spine02
• Arms: CC_Base_L_Clavicle, CC_Base_L_Upperarm, CC_Base_L_Hand
• Legs: CC_Base_L_Thigh, CC_Base_L_Foot, CC_Base_L_ToeBase

Skeletal Models (Betta Fish)

• Use armature bone names: Bone001_Armature, Bone002_Armature, etc.

Customizing 3D Markers

Edit DEFAULT_CONFIG in Annotation3DMarkers.ts:

const DEFAULT_CONFIG = {
  markerRadius: 0.012,           // Size of sphere on mesh surface
  markerColor: 0x4299e1,         // Blue color
  lineColor: 0x4299e1,           // Line color
  lineLength: 0.12,              // Line extension from surface
  labelColor: '#ffffff',         // Text color
  labelBackground: 'rgba(0, 0, 0, 0.75)', // Label background
  labelFontSize: 48,             // Font size for texture (higher = sharper)
  labelScale: 0.04,              // Label size in world units
};

Outward Direction for Markers

The direction markers point is determined semantically based on annotation name:

Important: For face-related markers (eyes, mouth, head), the outward direction must be FORWARD (+Z), not the direction from model center, because model center is typically at waist level and pointing from there to the face would hit the top of the head.

Surface Point Detection

3D markers use raycasting to place spheres on the mesh surface:

1. Calculate annotation center from bones/meshes
2. Determine semantic outward direction based on annotation type
3. Cast ray from outside model toward center along that direction
4. Use first intersection point as marker position
5. Offset slightly along surface normal to prevent z-fighting

Animation System

Camera transitions use spherical interpolation for smooth orbital motion:

• toSpherical() / fromSpherical() - coordinate conversion
• Pullback arc for large rotations (avoids passing through model)
• Ease-in-out timing function

Common Tasks

Add annotation for new body part

1. Identify bone/mesh names (check model in Three.js inspector)
2. Add annotation entry in annotations.ts
3. Set appropriate paddingFactor and cameraAngle

Adjust marker appearance

Edit Annotation3DMarkers.ts DEFAULT_CONFIG

Change animation timing

Modify transitionDuration in controller config or pass duration to focus methods

Debug camera positioning

Watch console logs prefixed with [Camera] - they show bounding boxes, positions, and angles