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Thomas M. Greiner, Ph.d.
01-16-1997, 06:00 AM
Thanks to all who took the time to reply to my request for
information about the 6D-Research system. The original posting was:

>I just received product information about the 6D-Research System
>from Skill Techologies, Inc. According to their flier:
> "6D-Research system tracks, quantifies, displays and documents
> true 3D motion of the human body. It is an accurate 6 degree-
> of-freedom (6DOF) system that captures and dynamically displays
> motion using 3D solid models and parameter graphs, in real time."
>Does anyone out there have experience with this, or a similar,
>system? Beyond the hype of the company's flier, I would like to know
>if this system will really live up to its claims.

I received several enthusiastic endorsements for the 6D-Research
System. By all accounts it does indeed accomplish what the flier
claims. Douglas Weber (doug.weber@asu.edu) stated that:
"It is so easy to set up an experiment, collect data, and instantly
study your results. You don't have to write any software to
convert marker trajectories into joint angles... There are no
problems with hidden or blended markers, and the system does
not require a calibration frame."

This, and similar, comments makes the system sound rather impressive.
The drawbacks that were identified are:
1) The subject is attached to the system through tethered wires.
These wires can make data collection difficult for non-rotational
movements. One respondent thought that a telemetered system
might be forthcomming, which would solve most of this problem.
2) The system tracks points within a magnetic field, so that the
proximity of some metal objects can disrupt data collection.
3) Display of motion is done in real-time, as claimed, but
actual numbers to describe that motion require
post-processing. Mark Cornwall (mark.cornwall.nau.edu) states
that calculating a number of data points and angles takes
from 10 - 20 seconds. So, this doesn't sound like that big of
a drawback.
4) A salesperson for another company suggested that I should
"Check into the financial part of the company for stability...
you'll want the company to be around for at least 10-15
years." This advice should probably apply to any expensive
equipment purchase.

Joy Mitra (joy@indra.psy.uconn.edu) provided a very detailed
description of the system's operation. In sum the 6D-Research system
integrates the Polhemus Fastrak with a graphical, menu-driven,
software interface. Because it is a magnetic system there is no
problem with the occulusion of markers (a common problem in optical
systems) since the subject (the human body) is transparent to the
magnetic field (although see drawback number 2 above). The hardware
has a high precision level, but only with about 6 feet of the
transmitter. Another advantage of this system is that it is
relatively inexpensive compared to some optical systems.

A number of persons asked about the name and address of the
company that supplies the 6D-Research System. That information is:
Skill Technologies, Inc.
1202 E. Maryland Ave, Suite 1G
Phoenix, Arizona 85014 USA
EMail: skilltech@primenet.com
Web Pages: http://www.primenet.com/~skilltec/

Finally, I also asked for information about similar systems. I was
provided with the following product names, companies, and web sites,
that should be "checked out."


Pohemus 3Space Fastrak
Web Page: http://www.polhemus.com

OPTOTRAK 3D Motion Measurement System
Contact: Joanne Yates
Northern Digital Inc.
403 Albert Street
Waterloo, Ontario
Canada N2L 3V2
EMail: jyates@ndigital.com

PROREFLEX by Qualysis
Contact: Victoria L. Berger
Innovision Systems, Inc.
8212 E. 12 Mile Road
Warren, MI 48093-2737 USA
EMail: victoria@innovision-systems.com
Web Page: www.innovision-systems.com

That's about it. Thank you again to all those who took the time to
respond to my querry.

Thomas Greiner

Thomas M. Greiner, Ph.D.
Department of Anatomy
New York Chiropractic College
Seneca Falls, NY 13148-0800

Phone: (315) 568-3183
Fax: (315) 568-3017
E-Mail: tgreiner@nycc.edu