Note that the waist markers are the key markers in modeling the pelvis bone, which is the major segment governing the other subsequent Skeleton segments. For best results, avoid placing the waist markers in a rectangle shape. When tracking multiple actors with similar proportions, introduce an offset to one of the WaistBack marker, or the WaistCMarker (included only with the 13 additional Marker Set), to create an asymmetrical arrangements.
When placing the shoulder markers, ask the actor to stand in the in order to place the markers on accurate locations. It could also be helpful to ask the actor to do few rounds of arm abduction and adduction to palpate for the shoulder axis. These markers determine the width of the shoulder and respective relationship with the upper arm segment.
For best results, place the hand markers so that the shape of the marker arrangement is asymmetrical itself and also unique to the shape on the other hand. Since the wrist marker placement is fixed along the wrist axis, offset the HandOut or the HandIn markers to create the unique arrangements. For more robust and simple tracking, hand rigid-bodies can be attached on the hand to replace the markers and guarantee the asymmetrical and non-deforming marker placement.
WaistLFront WaistRFront
Pelvis
Placed the marker on the protruding bone located on the front of the pelvis (left/right anterior iliac spine bone). The prominence can be palpated from left and right side of the waist.
WaistLBack WaistRBack
Pelvis
Place the WaistLBack and WaistRBack markers above left/right hip; about 10 cm above the hip joint.
BackTop
Torso
Place the marker on the spine right below the neck. For best results, LUArmHigh-LShoulderBack-BackTop-RshoulderBack-RUArmHigh markers should align roughly in a straight line when the actor is in T-pose. Also, note that this marker must be placed at an elevation higher than the chest marker for the torso segment to be tracked properly.
Chest
Torso
Place the marker at the center of the sternum, about 5 cm below where the neck starts.
BackLeft BackRight
Torso
These two markers are located symmetrically on each side of the back, slightly below the lowest end of the shoulder blade (scapular bone).
LShoulderBack RShoulderBack
Shoulder
Place the marker on the shoulder joint (glenohumeral joint) on the back.
LShoulderTop RShoulderTop
Shoulder
Place the marker at the top of each shoulder where you can palpate the protruding bone, which is usually located just before where the upper arm start when in T-pose. More specifically, the prominence is on the distal end of the clavicle bone (acrominoclavicular joint).
HeadTop
Head
Place the marker on the head tip.
HeadFront
Head
Place the marker at the center of the forehead.
HeadSide
Head
Place the marker on the either side of the head, slightly above the ear. When capturing multiple actors with similar proportions, place the marker on opposite side for clearer distinction.
LElbowOut RElbowOut
Upper Arm
Place the marker on the lateral side of the elbow joint, slightly towards the upper arm. More specifically, on the lateral epicondyle of the distal end of the humerous. Ask the actor to flex and extend the arm few times to confirm that markers are placed along the elbow axis and maintain stationary throughout the range of motion cycles.
LUArmHigh RUArmHigh
Upper Arm
Place the marker on the back of the upper arm near the groove between the triceps. For best results, LUArmHigh, LShoulderBack, BackTop, RshoulderNack, and RUArmHigh should align roughly in a straight line when in T-pose.
LWristOut RWristOut
Fore Arm / Hand
Place the marker on the outside (lateral side) of the wrist axis. (distal end of the radius bone). Note that the wrist axis is not always located on the protruding bone but 1-2 cm more towards the hand.
LWristIn RWristIn
Fore Arm / Hand
Place the marker on the inner prominence (medial side) of the wrist axis (distal end of the ulnar bone).
LHandOut RHandOut
Hand
Place the marker slightly below the pinky knuckle. More specifically, between distal end of the fifth and fourth mertacarpal bones.
Leardini, A., Biagi, F., Merlo, A., Belvedere, C., Benedetti, M.G., 2011. Multi-segment trunk kinematics during locomotion and elementary exercises. Clin. Biomech. 26, 562-571.
Leardini, A., Sawacha, Z., Paolini, G., Ingrosso, S., Nativo, R., Benedetti, M.G., 2007. A new anatomically based protocol for gait analysis in children. Gait Posture 26. 560-571.
Thorax
Cervical Spine Vertebra 7
The 7th cervical spine vertebra is the largest vertebra located at the most inferior region of the neck. This section usually protrudes to the posterior side and can be palpated.
TV2 (T2)
Thorax
Thoracic Spine Vertebra 2
The second thoracic spine vertebra is located three spine levels below the C7 vertebra. Which is located approximately at same height with shoulder joint markers.
TV7 (T7)
Thorax
Thoracic Spine Vertebra 7
Usually located at the center of the thoracic spinal column.
Upper Arm
Left Upper Arm Right Upper Arm
Ask the subject to stand in T-pose while placing the marker. Palpate to find the groove between the triceps muscles where skin movements are relatively minimal.
Not depicted in diagram
Forearm
Left Lower Arm Right Lower Arm
Place marker along the Ulna bone along the same line as the LUSP/RUSP marker
Hand
Left Radius Styloid Process Right Radius Styloid Process
Place the marker on the medial side of the wrist axis.
LAH RAH
Head
Left Anterior Head Right Anterior Head
Place the markers on the left and right side of the fore head. The respective location is shown in the Skeleton figure.
LPH RPH
Head
Left Posterior head Right Posterior head
Place the markers on the left and right side of the head about 2 cm behind the ear. The respective location is shown in the Skeleton figure.
SJN (IJ[1])
Thorax
Sternum Jugular Notch
Top most section of the sternum. Place the marker on the center of the two clavicle bones.
SXS (PX[1])
Thorax
Sternum Xiphoid Process
Lowest section of the sternum. Place the marker 1-2 cm above where bottom of the two rib cages conjoin.
Pelvis
Left Iliac Anterior Spine Right Iliac Anterior Spine
Place the marker on the protruding bones located on the left and right side of the pelvis front.
Pelvis
Left Iliac Posterior Spine Right Iliac Posterior Spine
Place each marker on the two dimples which can be palpated near the spine right above the hips.
Thorax
Left Clavicle-Acromion Joint Right Clavicle-Acromion Joint
Ask the subject to stretch both arms towards the side (T-pose), then palpate top of each shoulder for the protruding bone. The prominence is usually located at the end of the corresponding clavicle bone just before where the upper arm starts.
LHLE RHLE
Upper Arm
Left Humerus Lateral Epicondyle Right Humerus Lateral Epicondyle
Placed the markers on the lateral side of the elbow axis. Flex and extend the arm few times to find where elbow axis is located.
LHM2 RHM2
Hand
Left Hand Second metatarsal Right Hand Second metatarsal
Place the marker slight below the knuckle of the index finger.
LUSP RUSP
Hand
Left Ulna Styloid Process Right Ulna Styloid Process
Place the marker on the lateral side of the wrist axis.
CV7 (C7)
LUA RUA
LRSP RRSP