c3dfileeditor

A a script that reads, plots data as well as modifies c3d files using the btk library.

##Modules needed

###Python pacakges

numpy
Matplotlib
BTK

To install python2 packages you need to run pip. For example to install numpy, you need to run:

pip install numpy

BTK is the exception here. I was not able to get btk working through pip. BTK also seems to be architectural dependent as it was not installing in my ARCH distribution. I was able to get it working on Fedora 19 by installing the python wrapper package from here

https://code.google.com/p/b-tk/

Then run:

 yum localinstall packagename.rpm 

Running it

This program was hardcoded for the research I was doing in biomechanics. It graphs all the analog forces in the x,y, and z direction. Currently it modifies the file by setting a limit for the force in the z direction to mimic heal-toe running.

Before running this script you must add in the name of your c3d file. To do that you must edit this line.

reader = btk.btkAcquisitionFileReader()  # build a btk reader object 
reader.SetFilename('GaitNormal0003-processed.c3d')      # set a filename to the reader
acq = reader.GetOutput()                 # btk aquisition object

You can then run the program as follows:

 python c3dfileeditor.py modified.c3d 0.8 

where modified.c3d is the name you want your modified file to be and 0.8 is the cutoff.

The results are then graphed.

Sample Run:

###Unmodified c3d z axis

###Modified c3d file