gait analysis

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1

Hi,
I would like some directions to run the ‘GaitLowerExtremity’ using the attached c3d file.
Thanks
Chan

2

Hi Chan

The file contains a maker set for the lower extremities

Please have a look at the following webcast which shows how to use such a model.

AnyGait: Getting quickly from mocap to individualized musculoskeletal analysis (John Rasmussen, 15. December, 2009)

http://www.anybodytech.com/196.html

Please also read the main file of the model GaitLowerExctremity.Main.any which contains a number of steps to follow.

If you have any questions to this procedure please ask again.

Best regards
Søren

3

Thanks, I will try it and send you a feedback.

4

Hi Soren,
I followed the steps in the tutorial but there is a problem with the coordinate system orientation: in the ‘GaitLowerExtremity’ of the repository, the subject walks along the x-axis. But In my C3D file the subject walks along the y-axis. what modifications should I make to have it walk on the x-axis?
I am using the version 1.2 of the software.
Thanks
Chan

5

hi,

sorry i followed the link but can’t find anything? trying to get the gaitlower… to work.

thx

6

Hi,

For the link try this one: http://www.anybodytech.com/index.php?id=199.
You will find the complete list of webcast.

Chan, about the walking direction: you don’t have to modify it. If your model walks along the y axis then keep it that way. You just have to modify the gravity vector in the study to match your global orientation. That’s all.

Best regards, Sylvain.

7

Dear All,

Thanks for providing us with this forum. I have some questions here, regarding my model that uses c3d file.

I have made the model through a c3d file, and the model is pretty close to the c3d file (all the markers and the body segment), but I still have error below :

Position analysis failed : 268 independent constraints and 272 unknowns
- attempts to continue (attempt no. 1)
Failed to resolve kinematic constraints. Newton relaxation too small. (final kin. error = 1.717986E+012)
Constraint no. 0 above error tolerance 0.001000, error = 0.003828.
Constraint no. 1 above error tolerance 0.001000, error = 0.009920.
Constraint no. 2 above error tolerance 0.001000, error = 0.002119
.
.
.
and many more

and below, I have error like this:
Constraint no. #3 in ‘Main.Studies.KinematicStudyForParameterIdentification.HumanModel.BodyModel.Right.Leg.Jnt.PatellaFemur.Constraints’ above error tolerance 0.001000, error = 0.002413.
Constraint no. #4 in ‘Main.Studies.KinematicStudyForParameterIdentification.HumanModel.BodyModel.Right.Leg.Jnt.PatellaFemur.Constraints’ above error tolerance 0.001000, error = 0.002770.
Constraint no. #3 in ‘Main.Studies.KinematicStudyForParameterIdentification.HumanModel.BodyModel.Left.Leg.Jnt.PatellaFemur.Constraints’ above error tolerance 0.001000, error = 0.019906.

on this post, I attach also my model and the 3cd file. I really hope that someone from this forum can help me out.

Some of my colleagues suggested me that I should drive the trunk angle into zero. does any one know to which file I should change to drive the trunk angle into zero?

My model repository is : AMMRVI.1.3.1

Regards
Adhi
Groningen, NL