This tutorial explains how to implement OptiTracks Biomech (57) full body marker set^[1]. This full body marker set includes the head, torso, upper and lower body, hands and feet.

The naming convention used in this tutorial follows Serge Van Sint Jan's convention^[2].

LAH/RAH: Left/Right anterior head
LPH/RPH: Left/Right posterior head
SJN (IJ): Deepest point of incisura jugularis
SXS (PX): Xiphoid process, i.e. most caudal point of the sternum
CV7 (C7): Spinous process of the seventh cervical vertebrae
TV2 (T2): Second thoracic vertebrae
TV7 (MAI): Midpoint between the inferior angles of the most caudal points of the two scapulae
LHGT/RHGT: Left/Right glenohumeral Joint
LIAS/RIAS (LASIS/RASIS): Left/Right anterior superior iliac spine
LIPS/RIPS (LPSIS/RPSIS): Left/Right posterior superior iliac spine
LCAJ/RCAJ (LA/RA): Left/Right acromion
LHLE/RHLE: Left/Right humerus lateral epicondyle
LHME/RHME: Left/Right medial lateral epicondyle
LUA/RUA: Left/Right upper arm
LHM2/RHM: Left/Right hand second metatarsal
LUSP/RUSP: Left/Right ulna styloid process
LRSP/RRSP: Left/Right radius styloid process
LFTC/RFTC (LGT/RGT): Most lateral prominence of the greater trochanter
LFLE/RFLE (LLE/RLE): Most lateral prominence of the lateral femoral epicondyle
LFME/RFME (LME/RME): Most medial prominence of the medial femoral epicondyle
LTH/FTH: Left/Right thigh
LSK/RSK: Left/Right Superior knee
LTTC/RTTC (TT/RTT): Most anterior border of the tibial tuberosity
LFAX/RFAX (LHF/RHF): Proximal tip of the head of the fibula
LFAL/RFAL (LLM/RLM): Lateral prominence of the lateral malleolus
LTAM/RTAM (LMM/RMM): Most medial prominence of the medial malleolus
LFM5/RFM5 (LVM/RVM): Dorsal margin of the fifth metatarsal head
LFM1/RFM1 (LFM/RFM): Dorsal margin of the first metatarsal head
LFM2/RFM2 (LSM/RSM): Dorsal aspect of the second metatarsal head
LFCC/RFCC (LCA/RCA): Aspect of the achilles tendon insertion on the calcaneous
LDP1/RDP1: Left/Right distal phalanx

1. Create Head_Front:
Click Landmarks button
Click Add New Landmark button
Create Landmark: Head_Front

• Landmark Name: Head_Front
  
• Define Orientation Using:
  
  • Starting Point: RAH
    
  • Ending Point LAH
    
  • Offset Using the Following AXIAL Offset: 0.5
    
• Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

2. Create HEAD_PROXIMAL:
Click Landmarks button
Click Add New Landmark button
Create Landmark: HEAD_PROXIMAL

• Landmark Name: HEAD_PROXIMAL
  
• Define Orientation Using:
  
  • Existing Coordinate System: Thorax/Ab
    
  • Offset Using the Following AXIAL Offset: 1
    
• Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

3. Create HEAD_DISTAL:
Click Landmarks button
Click Add New Landmark button
Create Landmark: HEAD_DISTAL

• Landmark Name: HEAD_DISTAL
  
• Define Orientation Using:
  
  • Starting Point: Thorax_Prox
    
  • Ending Point Thorax_Dist
    
  • Project From Head_Front
    
• Do NOT Check: Offset by Percent (1.0 = 100%)
  
• Do NOT Check: Calibration Only Landmark
  

1. Create Head:
In the Segments tab, select Head in the Segment Name box.
Click on the Create Segment button.
In the Head tab, enter these values:

• Define Proximal Joint and Radius:
  
  • Lateral: None Joint: HEAD_PROXIMAL Medial: None
    
  • Radius: 0.5*DISTANCE(RAH,LAH)
    
• Define Distal Joint and Radius:
  
  • Lateral: none Joint: HEAD_DISTAL Medial: none
    
  • Radius: 0.5*DISTANCE(RPH,LPH)
    
• Extra Target to Define Orientation: Posterior, Head_Front
  
• Select Tracking Targets: LAH, LPH, RAH, RPH
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: -Z
  

1. Create Thorax_Dist:
Click Landmarks button
Click Add New Landmark button
Create Landmark: Thorax_Dist

• Landmark Name: Thorax_Dist
  
• Define Orientation Using:
  
  • Starting Point: SXS
    
  • Ending Point TV7
    
  • Offset Using the Following AXIAL Offset: 0.5
    
• Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

2. Create Thorax_Prox:
Click Landmarks button
Click Add New Landmark button
Create Landmark: Thorax_Prox

• Landmark Name: Thorax_Prox
  
• Define Orientation Using:
  
  • Starting Point: SJN
    
  • Ending Point CV7
    
  • Offset Using the Following AXIAL Offset: 0.5
    
• Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

3. Create Thorax_AP:
Click Landmarks button
Click Add New Landmark button
Create Landmark: Thorax_AP

• Landmark Name: Thorax_AP
  
• Define Orientation Using:
  
  • Starting Point: SJN
    
  • Ending Point SXS
    
  • Offset Using the Following AXIAL Offset: 0.5
    
• Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

1. Create Thorax/Ab:
In the Segments tab, select Thorax/Ab in the Segment Name box.
Click on the Create Segment button.
In the Thorax/Ab tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: None Joint: Thorax_Dist Medial: None
    
  • Radius: 0.5*DISTANCE(RCAJ,LCAJ)
    
• Define Distal Joint and Radius
  
  • Lateral: none Joint: Thorax_Prox Medial: none
    
  • Radius: 0.5*DISTANCE(RCAJ,LCAJ)
    
• Extra Target to Define Orientation: Posterior, Thorax_AP
  
• Select Tracking Targets: CV7, SJN, SXS, TV7
  
• Depth: 0.5*DISTANCE(CV7,SJN)
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: -Z
  

1. Create LSJC Joint Center:
Click Landmarks button
Click Add New Landmark button
Create Landmark: LSJC

• Landmark Name: LSJC
  
• Define Orientation Using:
  
• Starting Point: LCAJ
  
• Existing Coordinate System: Thorax/Ab
  
• Offset Using the Following AXIAL Offset: -(LShoulderRadius+MarkerRadius)
  
• Do NOT Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

1. Create Left Forearm:
In the Segments tab, select Left Upper Arm in the Segment Name box.
Click on the Create Segment button.
In the Upper arm tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: None  Joint: LSJC  Medial: None
    
  • Radius: LShoulderRadius
    
• Define Distal Joint and Radius
  
  • Lateral: LHLE   Joint: None   Medial: LHME
    
• Select Tracking Targets: LHLE, LHME, LUA,
  
• Click on Build Model.
  
• Click on Close Tab before proceeding.
  

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:
*A/P Axis: +Y
*Distal to Proximal: +Z

1. Create LT_ELBOW Joint Center:
Click Landmarks button
Click Add New Landmark button
Create Landmark: LT_ELBOW

• Landmark Name: LT_ELBOW
  
• Define Orientation Using:
  
  • Existing Coordinate System: Left Upper Arm
    
  • Offset Using the Following AXIAL Offset: -1.0
    
• Check: Offset by Percent (1.0 = 100%)
  
• Do NOT Check: Calibration Only Landmark
  

1. Create Left Forearm:
In the Segments tab, select Left Forearm in the Segment Name box.
Click on the Create Segment button.
In the Left Forearm tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: None  Joint: LT_ELBOW  Medial: None
    
  • Radius: 0.0548641
    
• Define Distal Joint and Radius
  
  • Lateral: LRSP   Joint: None   Medial: LUSP
    
• Select Tracking Targets:
   Use Calibration Targets for Tracking
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: +Z
  

1. Create LWJC Joint Center
Click Landmarks button
Click Add New Landmark button
Create Landmark: LWJC

• Landmark Name: RANK\\ 
• Define Orientation Using:
  
  • Starting Point: LRSP Ending Point: LUSP
    
• Offset Using the Following ML/AP/AXIAL Offsets:
  
  • X: 0.0 Y: 0.0 Z: 0.5
    

Check: Offset by Percent (1.0 = 100%)
Do NOT Check: Calibration Only Landmark

2. Create LHJC Joint Center
Click Landmarks button
Click Add New Landmark button
Create Landmark: LHJC

• Landmark Name: RANK
  
• Define Orientation Using:
  
  • Starting Point: LT_ELBOW
    
  • Ending Point: LWJC
    
  • Project From: LHM2
    
• Offset Using the Following ML/AP/AXIAL Offsets:
  
  • X: 0.0 Y: 0.0 Z: 0.0
    
• Do NOT Check: Offset by Percent (1.0 = 100%)
  
• Check: Calibration Only Landmark
  

1. Create Left Hand:
In the Segments tab, select Left Hand in the Segment Name box.
Click on the Create Segment button.
In the Left Hand tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: None   Joint: LWJC  Medial: None
    
  • Radius: LWristRadius
    
• Define Distal Joint and Radius
  
  • Lateral: none  Joint: LHJC  Medial: none
    
• Select Tracking Targets:
   LHM2, LRSP, LUSP
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: +Z
  

1. Create Pelvis Segment:
In the Segments tab, select Pelvis in the Segment Name box.
In Segment Type, select V3D_Composite
Click on the Create Segment button.
In the Pelvis dialog:

• Define Calibration Targets
  
  • R.ASIS: RIAS  L.ASIS: LIAS  R.PSIS: RIPS  L.PSIS: LIPS
    
• Check Use Calibration Targets for Tracking
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
     
• Distal to Proximal: +Z
  

1. Create LEFT_HIP Joint Center:
Click Landmarks button
Click Add New Landmark button
Create Landmark: LEFT_HIP

• Landmark Name: LEFT_HIP
  
• Define Orientation Using:
  
  • Existing Coordinate System Pelvis
    
  • Landmark Offset from Start Point or Segment Origin
    
  • ML: -0.36*ASIS_Distance*RPV_ML_Direction
    
  • AP: 0.19*SASIS_Distance*RPV_AP_Direction+0.5*:RPV_Depth - Target_Radius_ASIS
    
  • AXIAL: -0.30*ASIS_Distance*RPV_Axial_Direction
    
• Do NOT Check: Offset by Percent (1.0 = 100%)
  
• Do NOT Check: Calibration Only Landmark
  

1. Create Left Thigh:
In the Segments tab, select Left Thigh in the Segment Name box.
Click on the Create Segment button.
In the Left Thigh tab, enter these values:

• Define Proximal Joint and Radius\\  Lateral: None  Joint: LEFT_HIP  Medial: None
  
  • Radius: 0.5*DISTANCE(RIGHT_HIP,LEFT_HIP)
    
• Define Distal Joint and Radius
  
  • Lateral: LFLE  Joint: None  Medial: LFME
    
• Select Tracking Targets: LEFT_HIP, LFLE, LFME, LFTC, LTH
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: +Z
  

1. Create Left Shank:
In the Segments tab, select Left Shank in the Segment Name box.
Click on the Create Segment button.
In the Left Shank tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: LFLE  Joint: none  Medial: LFME
    
• Define Distal Joint and Radius
  
  • Lateral: LFAL  Joint: None  Medial: LTAM 
    
• Select Tracking Targets: LFAL, LFAX, LTAM, LTTC
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: +Z
  

1. Create Left Foot:
In the Segments tab, select Left Foot in the Segment Name box.
Click on the Create Segment button.
In the Left Foot tab, enter these values:

• Define Proximal Joint and Radius
  
  • Lateral: LFAL  Joint: none  Medial: LTAM
    
• Define Distal Joint and Radius
  
  • Lateral: LFM5  Joint: None  Medial: LFM1\\  
• Select Tracking Targets: LDP1, LFCC, LFM1, LFM2, LFM5
  

Click on Build Model.
Click on Close Tab before proceeding.

2. Modify the Segment Coordinate System:
Define the Segment Orientation as:

• A/P Axis: +Y
  
• Distal to Proximal: +Z
  

1. ↑ OptiTrack Biomech(57) https://docs.optitrack.com/movement-sciences/movement-sciences-markersets/biomech-57
2. ↑ Serge van Sint Jan “Color Atlas of Skeletal Landmark Definitions: Guidelines for Reproducible Manual and Virtual Palpations” 2007 - Churchill Livingstone