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). One message per frame, time-aligned with head and hand pose.

EgoSuite publishes body pose on three topics: the 22-joint full body on /pose/body, plus two subsets extracted from it — the 14-joint upper body on /pose/upper_body and the 8-joint lower body on /pose/lower_body. Both subsets are reindexed compactly starting from 0.

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.

Topics & Message Types

Topic	Message Type	Joints	Description
/pose/body	pose.BodyFrame	22	Full-body skeleton
/pose/upper_body	pose.UpperBodyFrame	14	Upper-body subset (reindexed 0–13)
/pose/lower_body	pose.LowerBodyFrame	8	Lower-body subset (reindexed 0–7)

• Encoding: protobuf

All three use pose_common Transform (position + quaternion) per joint.

Message definitions:

syntax = "proto3";
package pose;
import "common/header.proto";
import "pose/pose_common.proto";

// Full 22-joint body. Topic: /pose/body
message BodyFrame {
  .common.header.Header header = 1;
  repeated pose.common.Transform transforms = 2;
}

// Upper-body subset, 14 joints. Topic: /pose/upper_body
message UpperBodyFrame {
  .common.header.Header header = 1;
  repeated pose.common.Transform transforms = 2;
}

// Lower-body subset, 8 joints. Topic: /pose/lower_body
message LowerBodyFrame {
  .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 Position {
  double x = 1;
  double y = 2;
  double z = 3;
}

message Transform {
  Position pos = 1;
  Quaternion quat = 2;
}

Joint Index and Conventions

/pose/body — 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

/pose/upper_body — 14-Joint Upper Body

The upper-body topic publishes 14 joints (index 0–13), extracted from the 22-joint full-body skeleton and reindexed compactly. It is not the first 14 entries of the 22-joint layout.

Joints extracted (by 22-joint index): 0, 3, 6, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21.

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

/pose/lower_body — 8-Joint Lower Body

The lower-body topic publishes 8 joints (index 0–7), extracted from the 22-joint full-body skeleton and reindexed compactly.

Joints extracted (by 22-joint index): 1, 2, 4, 5, 7, 8, 10, 11.

Index	Name	22-index	Index	Name	22-index
0	L_Hip	1	4	L_Ankle	7
1	R_Hip	2	5	R_Ankle	8
2	L_Knee	4	6	L_Foot	10
3	R_Knee	5	7	R_Foot	11

The /pose/upper_body and /pose/lower_body topics together cover all 22 joints of /pose/body, so consumers can use whichever granularity fits their use case.