International Society of Biomechanics
Gold sponsor

Restricted Access Notice

Access to our files is only available if you are logged in as a member

Rigid Body Position and Attitude Estimation

In 3-D kinematic analysis of movement, we typically track the motion of three or more markers on a rigid body segment. Here are various methods to extract a 3-D position vector and rotation (or attitude) matrix from marker coordinates.

H.J. Woltring.

A Fortran subroutine, using the eigenvalue decomposition method described in: Veldpaus et al., J. Biomech. 21,45-54 (1988).

Joe Sommer

FORTRAN subroutines and test data for finite helical axis (FHA) and instant screw axis (ISA).

Ron Jacobs, Ton van den Bogert

A Matlab function using singular value decomposition. Includes references.

This email address is being protected from spambots. You need JavaScript enabled to view it.

An Excel spreadsheet that converts Euler X-Y-Z rotation angles to the other 5 possible rotation sequences as well as to the tilt-twist angles. Instructions are included in the spreadsheet.