> ## Documentation Index > Fetch the complete documentation index at: https://docs.nomadicml.com/llms.txt > Use this file to discover all available pages before exploring further. # Dexterous hands > Two multi-finger hands on two arms, with 22 joint angles and a force-torque wrench per fingertip. A bimanual robot with dexterous hands declares each hand as a `hand` part with its joint angles, and its tactile or fingertip force sensing as the hand's `force`. This example is two Sharpa Wave hands (22 DoF each) on two 7-DoF arms, using the recognised [embodiment](/mcap-spec/body-and-parts#recognised-embodiments) `sharpa_wave_bimanual`, with the recording's subtasks as [segments](/mcap-spec/recording#segments). ## Channels | Channel | Message | Content | | - | - | - | | `/cam/top`, `/cam/front` | `foxglove.CompressedVideo` | scene cameras | | `/left_arm/flange_pose`, `/right_arm/flange_pose` | `foxglove.PoseInFrame` | hand-flange poses in the robot base frame | | `/sig/left_hand_joints`, `/sig/right_hand_joints` | `nomadic.Signal` | 22 joint angles per hand | | `/sig/left_fingertip_wrench`, `/sig/right_fingertip_wrench` | `nomadic.Signal` | a 6-axis wrench per fingertip, 30 values per hand | ## Overlay ```json overlay.json theme={null} { "spec_version": "1.1", "recording": { "id": "dexterous-wipe-000318", "clock": "log_time", "t0_ns": 1760000000000000000, "task": { "instruction": "Pick up the plate and wipe it with the eraser.", "scene": "A plate with marks and an eraser are on the table.", "success_criteria": "The marks are removed and both objects are back on the table." }, "segments": [ {"start_s": 0.0, "end_s": 21.9, "text": "Pick up the plate with the left hand.", "label": "subtask", "skill": "pick", "id": "subtask-001"}, {"start_s": 21.9, "end_s": 24.3, "text": "Pick up the eraser with the right hand.", "label": "subtask", "skill": "pick", "id": "subtask-002"}, {"start_s": 24.3, "end_s": 41.0, "text": "Wipe the plate with the eraser.", "label": "subtask", "skill": "wipe", "id": "subtask-003"} ], "platform": { "kind": "manipulator", "embodiment": "sharpa_wave_bimanual", "parts": [ {"name": "left_arm", "type": "arm", "side": "left", "end_pose": {"channel": "/left_arm/flange_pose"}}, {"name": "right_arm", "type": "arm", "side": "right", "end_pose": {"channel": "/right_arm/flange_pose"}}, {"name": "left_hand", "type": "hand", "side": "left", "joints": {"signal": "left_hand_joints", "names": ["left_thumb_CMC_FE", "left_thumb_CMC_AA", "left_thumb_MCP_FE", "left_thumb_MCP_AA", "left_thumb_IP", "left_index_MCP_FE", "left_index_MCP_AA", "left_index_PIP", "left_index_DIP", "left_middle_MCP_FE", "left_middle_MCP_AA", "left_middle_PIP", "left_middle_DIP", "left_ring_MCP_FE", "left_ring_MCP_AA", "left_ring_PIP", "left_ring_DIP", "left_pinky_CMC", "left_pinky_MCP_FE", "left_pinky_MCP_AA", "left_pinky_PIP", "left_pinky_DIP"]}, "force": {"signal": "left_fingertip_wrench"}}, {"name": "right_hand", "type": "hand", "side": "right", "joints": {"signal": "right_hand_joints", "names": ["right_thumb_CMC_FE", "right_thumb_CMC_AA", "right_thumb_MCP_FE", "right_thumb_MCP_AA", "right_thumb_IP", "right_index_MCP_FE", "right_index_MCP_AA", "right_index_PIP", "right_index_DIP", "right_middle_MCP_FE", "right_middle_MCP_AA", "right_middle_PIP", "right_middle_DIP", "right_ring_MCP_FE", "right_ring_MCP_AA", "right_ring_PIP", "right_ring_DIP", "right_pinky_CMC", "right_pinky_MCP_FE", "right_pinky_MCP_AA", "right_pinky_PIP", "right_pinky_DIP"]}, "force": {"signal": "right_fingertip_wrench"}} ] } }, "primary_view": "/cam/top", "views": [ {"channel": "/cam/top", "role": "top", "label": "Overhead"}, {"channel": "/cam/front", "role": "front", "label": "Front"} ], "signals": [ {"channel": "/sig/left_hand_joints", "name": "left_hand_joints", "type": "vector", "dim": 22, "unit": "rad", "rate_hz": 100, "components": ["left_thumb_CMC_FE", "left_thumb_CMC_AA", "left_thumb_MCP_FE", "left_thumb_MCP_AA", "left_thumb_IP", "left_index_MCP_FE", "left_index_MCP_AA", "left_index_PIP", "left_index_DIP", "left_middle_MCP_FE", "left_middle_MCP_AA", "left_middle_PIP", "left_middle_DIP", "left_ring_MCP_FE", "left_ring_MCP_AA", "left_ring_PIP", "left_ring_DIP", "left_pinky_CMC", "left_pinky_MCP_FE", "left_pinky_MCP_AA", "left_pinky_PIP", "left_pinky_DIP"]}, {"channel": "/sig/right_hand_joints", "name": "right_hand_joints", "type": "vector", "dim": 22, "unit": "rad", "rate_hz": 100, "components": ["right_thumb_CMC_FE", "right_thumb_CMC_AA", "right_thumb_MCP_FE", "right_thumb_MCP_AA", "right_thumb_IP", "right_index_MCP_FE", "right_index_MCP_AA", "right_index_PIP", "right_index_DIP", "right_middle_MCP_FE", "right_middle_MCP_AA", "right_middle_PIP", "right_middle_DIP", "right_ring_MCP_FE", "right_ring_MCP_AA", "right_ring_PIP", "right_ring_DIP", "right_pinky_CMC", "right_pinky_MCP_FE", "right_pinky_MCP_AA", "right_pinky_PIP", "right_pinky_DIP"]}, {"channel": "/sig/left_fingertip_wrench", "name": "left_fingertip_wrench", "type": "vector", "dim": 30, "rate_hz": 100, "note": "one wrench per fingertip, N and N*m", "components": ["thumb_fx", "thumb_fy", "thumb_fz", "thumb_tx", "thumb_ty", "thumb_tz", "index_fx", "index_fy", "index_fz", "index_tx", "index_ty", "index_tz", "middle_fx", "middle_fy", "middle_fz", "middle_tx", "middle_ty", "middle_tz", "ring_fx", "ring_fy", "ring_fz", "ring_tx", "ring_ty", "ring_tz", "pinky_fx", "pinky_fy", "pinky_fz", "pinky_tx", "pinky_ty", "pinky_tz"]}, {"channel": "/sig/right_fingertip_wrench", "name": "right_fingertip_wrench", "type": "vector", "dim": 30, "rate_hz": 100, "note": "one wrench per fingertip, N and N*m", "components": ["thumb_fx", "thumb_fy", "thumb_fz", "thumb_tx", "thumb_ty", "thumb_tz", "index_fx", "index_fy", "index_fz", "index_tx", "index_ty", "index_tz", "middle_fx", "middle_fy", "middle_fz", "middle_tx", "middle_ty", "middle_tz", "ring_fx", "ring_fy", "ring_fz", "ring_tx", "ring_ty", "ring_tz", "pinky_fx", "pinky_fy", "pinky_fz", "pinky_tx", "pinky_ty", "pinky_tz"]} ] } ``` ## Notes * **Joint names.** For a recognised embodiment, joint `names` MUST match the robot's URDF joint names, in the order of your vector. For any other hand, use your own names. * **Arms without joints.** Each arm here carries only its flange pose. Add `joints` when you log the arm's joint angles. * **Fingertip force forms.** A full wrench per fingertip uses components `_fx … _tz`, six per fingertip. A sensor that measures only normal force uses the contact-force form instead: `unit: "N"`, one value per fingertip, e.g. components `["thumb", "index", "middle", "ring", "pinky"]`. See [Force](/mcap-spec/body-and-parts#force). * **Hands on arms.** `left_hand` is paired with `left_arm`, whose `end_pose` is the hand flange, so the hands need no `end_pose` of their own. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.