Body Pose

Overview

Body pose is a skeleton in the world frame: each joint has position (x, y, z in meters) and orientation (quaternion w, x, y, z). EgoSuite body data can use either a 22-joint full-body layout or a 14-joint upper-body layout. One message per frame, time-aligned with head and hand pose.

Coordinate Frame

• Reference frame: World.
• Axes: X forward, Y left, Z up (right-handed).
• Units: Position in meters.
• Orientation: Quaternion in w, x, y, z order.

Topic & Message Type

• Topic: /pose/body
• Message type: pose.BodyFrame
• Encoding: protobuf

BodyFrame uses pose_common for each joint: header plus repeated Transforms. Check len(transforms) to determine the layout:

• 22 transforms: full-body layout, indices 0–21.
• 14 transforms: upper-body-only layout, indices 0–13.

Message definition (body, one message per frame):

syntax = "proto3";

package pose;

import "common/header.proto";
import "pose/pose_common.proto";

message BodyFrame {
  .common.header.Header header = 1;
  repeated pose.common.Transform transforms = 2;
}

Transform type (from pose/pose_common.proto):

syntax = "proto3";

package pose.common;

message Quaternion {
  double w = 1;
  double x = 2;
  double y = 3;
  double z = 4;
}

message Transform {
  Quaternion quat = 1;
  double x = 2;
  double y = 3;
  double z = 4;
}

Joint Index and Conventions

22-Joint Full Body

The full-body layout uses 22 joints (index 0–21). Joint indices and skeleton connectivity:

Index	Name	Index	Name
0	Pelvis	11	R_Foot
1	L_Hip	12	Neck
2	R_Hip	13	L_Collar
3	Spine_01	14	R_Collar
4	L_Knee	15	Head
5	R_Knee	16	L_Shoulder
6	Spine_02	17	R_Shoulder
7	L_Ankle	18	L_Elbow
8	R_Ankle	19	R_Elbow
9	Spine_03	20	L_Wrist
10	L_Foot	21	R_Wrist

14-Joint Upper Body

The upper-body layout uses 14 joints (index 0–13). It is the full-body skeleton with lower-limb joints removed, then reindexed compactly. It is not the first 14 entries of the 22-joint layout.

Removed lower-body joints from the 22-joint layout:

• L_Hip (1), R_Hip (2)
• L_Knee (4), R_Knee (5)
• L_Ankle (7), R_Ankle (8)
• L_Foot (10), R_Foot (11)

Upper-body joint indices:

Index	Name	22-index	Index	Name	22-index
0	Pelvis	0	7	Head	15
1	Spine_01	3	8	L_Shoulder	16
2	Spine_02	6	9	R_Shoulder	17
3	Spine_03	9	10	L_Elbow	18
4	Neck	12	11	R_Elbow	19
5	L_Collar	13	12	L_Wrist	20
6	R_Collar	14	13	R_Wrist	21

For visualization, the devkit treats 14-joint body data as upper-body only and does not emit a lower-body skeleton. When 22-joint body data is present, the lower-body skeleton is generated from the hip, knee, ankle, and foot joints.