Chapter 3 Customized Kinematic Model

Creating Custom Mark Sets and Using VICON Autolabel Function to Generate a Model Designed by You

• Marker names and placement specific to your own model

• Create different displays with custom linkages

• Add additional objects into an existing .mkr file

3.1 Why Customize?

• At least 3 marks should be placed on a single segment

• All marks on a segment should NOT be set on a line

• Usually, put a mark on each distal and primal end of a segment (joint centers) to shape the segment

3.2 Essentials of Mark Setting

3.3 Format of .mkr File

• Simple text file, can be created with notepad

• Specialized header

• Sections distinguished by square brackets

Sample.mkr

!MKR#2

[section 1]

Marker1 Description1

[section 2]

Etc…

• Labels

• Linkages

• Grouping (definitions of joints and segments)

• Hierarchy (model definition)

3.4 Essential Sections in a .mkr file

• .Mkr file consists of labels which can be assigned to markers

• Labels have custom linkages drawn by the author which may or may not be significant to the model

• Any label can be assigned to any marker

Labels vs. Markers

• First column: marker name

• Second column: description (optional)

Declaring Markers

!MKR#2

[labels]

RFHD Right Front Head

LFHD Left Front Head

RBHD Right Back Head

LBHD Left Back Head

Drawing Linkages

• Listing markers draws lines between every possible marker

LASI,RASI,LPSI,RPSI

Drawing Linkages

• Listing only two markers per line allows custom displays

LASI,RASIRASI,RPSIRPSI,LPSILPSI,LASI

The Autolabel Section

• Format of section is important

• Groupings declared

• Root grouping = grouping with the most markers or grouping named as “root”

• Root grouping should be rigid (i.e pelvis)

• Groupings are linked as a segmental hierarchy

Declaring a Grouping

Head = LFHD,RFHD,LBHD,RBHD

Thorax = C7,T10,CLAV,STRN,LBAK,RBAK

LeftShoulder = LSHO,CLAV,T10

LeftUpperArm = LSHO,LUPA,LELB

LeftLowerArm = LELB,LFRA,LWRA,LWRB

LeftHand = LFIN

Linking the Hierarchy

Head,Thorax

Thorax,Pelvis

Pelvis,LeftUpperLeg

Pelvis,RightUpperLeg

LeftLowerArm,LeftHand

RightLowerArm,RightHand