README.md

metadata

pretty_name: Lance Captured Trajectory Dataset
language:
  - en
tags:
  - lance
  - trajectory
  - mano
  - robotics
  - motion-capture
task_categories:
  - robotics
  - time-series-forecasting

lance_dataset

This repository stores Lance datasets.

The current dataset is organized as Dexcanvas.lance/. It contains Lance data fragments, version manifests, and transaction metadata.

Dataset Structure

Dexcanvas.lance represents a captured trajectory dataset. Each row corresponds to one complete captured trajectory. The field definitions are based on captured_data_schema.yaml.

Key conventions:

• trajectory_metadata.total_frames defines the sequence length T
• All sequence fields must have the same T dimension
• All rotations are represented in axis-angle format
• All positions are measured in meters

MANO Trajectory Fields

MANO-related data is split into metadata fields and time-series fields.

Metadata

The following fields in trajectory_metadata describe the hand layout:

• hand_names: variable-length list of hand names
• mano_hand_shapes: MANO shape parameters for each hand

Index mapping:

• hand_names[i] corresponds to hands[i]
• mano_hand_shapes[i] corresponds to hands[i]

Time-Series Data

hands[] is a variable-length array. Each element represents one hand over the full trajectory.

• mano_global_pos (T, 3)
  Global hand position in meters.
• mano_global_rot_aa (T, 3)
  Global hand rotation in axis-angle format.
• mano_hand_pose (T, 48)
  MANO hand pose parameters.
  • 45 dimensions for 15 joint rotations
  • 3 dimensions for the wrist
• mano_joint_pos (T, 21, 3)
  3D positions of 21 MANO hand joints.
• urdf_dof (T, 26)
  URDF degree-of-freedom representation.
  • 20 finger DOFs
  • 6 wrist DOFs

In short:

• mano_global_pos and mano_global_rot_aa describe the global hand pose
• mano_hand_pose describes MANO finger and wrist pose parameters
• mano_joint_pos provides the derived 3D hand joint positions
• urdf_dof provides a robot/control-oriented representation

Object Fields

Object-related data is stored in trajectory_metadata.object_names and objects[].

Metadata

• object_names: variable-length list of object names

Index mapping:

• object_names[i] corresponds to objects[i]

Time-Series Data

objects[] is a variable-length array. Each element represents one object over the full trajectory.

• rot_aa (T, 3)
  Object rotation in axis-angle format.
• pos (T, 3)
  Object position in meters.

Therefore, objects[i] stores the full pose trajectory of the i-th object across all T frames.

Other Common Fields

• index.uuid: unique trajectory identifier
• index.seed_uuid: same as uuid for captured data; source trajectory ID for generated data
• index.file_uuid: source session_data_files.file_uuid
• index.capMachine: capture machine identifier
• index.operator: operator who captured or generated the data
• index.scene: scene identifier
• index.is_generated: whether the row is generated data
• timestamp: per-frame timestamps
• atomic_actions: atomic action intervals, such as grasp or release

Directory Layout

• Dexcanvas.lance/: Lance dataset root
• Dexcanvas.lance/data/: physical Lance data fragments
• Dexcanvas.lance/_versions/: dataset version manifests
• Dexcanvas.lance/_transactions/: transaction records
• Dexcanvas.lance/_latest.manifest: latest dataset manifest
• captured_data_schema.yaml: YAML schema converted from the upstream JSONC schema

Notes

When adding new fields, keep them consistent with captured_data_schema.yaml, especially:

• The shared T dimension for sequence fields
• The index mapping between hands[] and trajectory_metadata.hand_names
• The index mapping between objects[] and trajectory_metadata.object_names
• Axis-angle rotation representation