how to scale all point data?

[Sol Hator]

Dear BTK Development Team

We found that for some reason Vicon plots our data
basically as one point, interpreting meters as millimeters.

Therefore how can we scale, i.e. multiply all point data by a
constant factor, before writing the acquisition to a new file?

We are using the BTK Python Wrapper.

I tried using SetPointScale() but I either used it wrong,
or it is not the function for this task.

Best wishes
Nicolas Kuske

PS:
the documentation could be a little bit wordier, and
maybe include some more examples

[Sol Hator]

At the moment we are manually multiplying each point coordinate by 1000.
This seems unnecessarily time consuming

[Arnaud Barré]

Did you try to set the point unit to 'm' using the method 'btk.btkAcquisition.SetPointUnit' [1] ?

[1] http://b-tk.googlecode.com/svn/doc/Python/0.3/classbtk_1_1btk_acquisition.html#ae2021cb1a7b3000ee0720cc8b630328f

On 2015-11-19, at 11:28 AM, Sol Hator <solh...@gmail.com> wrote:

> At the moment we are manually multiplying each point coordinate by 1000.
> This seems unnecessarily time consuming
>

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[Sol Hator]

I tried before yes.
Now I tried again ;)
Vicon still does not react...

reader = btk.btkAcquisitionFileReader()
reader.SetFilename(file)
reader.Update()
acq=reader.GetOutput()

acq.SetPointUnit('m')
acq.Update()

writer = btk.btkAcquisitionFileWriter()
writer.SetInput(acq)
writer.SetFilename(file)
writer.Update()

[Arnaud Barré]

I would say this is a Vicon bug :-)

You should contact their support and ask if they support only C3D files with the millimetre unit for the marker's coordinates.

Arnaud