M.010.07 — Dual-Phone Volumetric Capture (Execution Spec)

Date: 2026-04-04
Owner: Copilot execution lane
Status: Ready for implementation

Goal

Use two phones as a calibrated stereo pair to capture 3D objects and export them into .holo scene assets with usable geometry + texture alignment.

Product behavior

1. Primary phone starts capture session and generates pairing QR.
2. Secondary phone joins and syncs timestamps.
3. Both devices record synchronized multi-view frames while user circles object.
4. Reconstruction pipeline fuses depth/stereo + pose streams into mesh.
5. Output is packaged as .holo object block + referenced texture assets.

Core constraints

• Clock skew budget: < 20ms between capture streams
• Pose drift must be corrected with periodic visual marker relocalization
• Export must include confidence metadata to avoid false precision in Studio

Technical architecture

Capture session

• Session roles: host and peer
• Shared session metadata:
  • sessionId
  • camera intrinsics
  • calibration baseline
  • capture framerate target

Synchronization

• Time sync handshake at join + periodic drift correction
• Frame envelope:

interface StereoFrameEnvelope {
  sessionId: string;
  deviceRole: 'host' | 'peer';
  timestampMs: number;
  pose: {
    position: [number, number, number];
    rotation: [number, number, number, number];
  };
  intrinsics: number[];
  imageRef: string;
  depthRef?: string;
}

Reconstruction pipeline

1. Pair frame windows by nearest synchronized timestamps
2. Triangulate sparse points using stereo correspondences
3. Fuse with depth maps when available
4. Build mesh + run hole filling + smoothing (bounded)
5. UV unwrap + texture bake
6. Emit .holo template/object payload

Export contract

• Geometry output: model/<sessionId>.glb
• Texture output: textures/<sessionId>_albedo.png
• .holo reference snippet includes quality/confidence fields

Proposed code touch points

• packages/runtime/ — capture session orchestrator + sync protocol
• packages/core/ — .holo exporter extension for volumetric capture metadata
• packages/studio/ — import panel for dual-phone capture output + confidence badges

Failure taxonomy

• PAIRING_TIMEOUT
• TIME_SYNC_DRIFT_EXCEEDED
• INSUFFICIENT_PARALLAX
• RECONSTRUCTION_LOW_CONFIDENCE
• EXPORT_SERIALIZATION_FAILED

Acceptance criteria

1. Two-device pairing succeeds in < 15s under local network conditions.
2. Captured object reconstructs into valid mesh and imports into Studio.
3. Exported .holo scene reference resolves assets without manual patching.
4. Capture confidence score is exposed and persisted in output metadata.
5. Failure modes produce actionable user guidance (reposition, relight, recapture).

Test plan

Unit

• frame pairing logic under timestamp jitter
• sync drift correction math
• export schema validation

Integration

• synthetic dual-stream reconstruction test
• degraded network simulation for pairing/sync resilience
• low-parallax capture failure path

Device validation

• Android + Android pair
• iOS + iOS pair
• mixed pair (feature-flag if unsupported in v1)

Shipping slices

• Slice A: Pairing + sync protocol + schema tests
• Slice B: Reconstruction core + mesh export path
• Slice C: Studio ingestion + confidence UX + end-to-end demo

Metrics

• stereo_pair_success_rate
• capture_sync_drift_ms
• reconstruction_success_rate
• export_success_rate
• capture_to_import_latency_ms

Definition of done

• End-to-end dual-phone capture -> .holo import demonstrated
• acceptance criteria pass
• confidence metadata and error guidance available in Studio
• docs updated for operator workflow and known limitations