BTK MatLab tools for C3D files not working

[Karen Roemer]

Hi!

I hope someone here can help me out: I have been using the BTK tools for MatLab to extract data from C3D files for years. Since about a week ago, I am not able to run any of my scripts anymore (2 different Mac's) and get the following error message:

Invalid MEX-file '/Volumes/IMAC_EXTERNAL/btk/btkReadAcquisition.mexmaci64':
dlopen(/Volumes/IMAC_EXTERNAL/btk/btkReadAcquisition.mexmaci64, 6): Library not loaded:
@loader_path/libmex.dylib
Referenced from: /Volumes/IMAC_EXTERNAL/btk/btkReadAcquisition.mexmaci64
Reason: image not found.

It does not matter which BTK routine I try to call, all end up with the same error message.

Has anyone an idea how to solve this problem or maybe experienced similar issues ??
I did not change my script and it worked until recently.

Any input to get this problem resolved would be highly appreciated

Thanks

Karen

[Adam Clansey]

Re: BTK MatLab tools for C3D files not working

Hi Karen,

Are you using 32bit or 64bit Matlab version? It maybe a compatibility issue. BTK tools can come in 32bit and 64bit.

Best,
Adam

[Karen Roemer]

Re: BTK MatLab tools for C3D files not working

Hi Adam,

I am using 64 bit version for both (MatLab and BTK). I think that the BTK tools need to be re-compiled to work with the newest MatLab version. The newest toolbox on the BTK web-site is from 2014 and my issues started with updating MatLab to 2018a.

Karen

[James Dunne]

Re: BTK MatLab tools for C3D files not working

Hi, Karen-

I saw your post and I have Matlab 2018 on a Mac with the BTK source, so I recompiled the Mex functions as a static library. It works on my local system but I don't have a secondary Mac to test the libraries on. Download the library here and put it on your Matlab path. If that doesn't work, it is relatively easy to compile locally. BTK is no longer maintained by the creator so it may be worth knowing how to compile from source.

BTK has been forked into OpenSim, so there will be an easy Matlab method for reading c3d files when the next OpenSim release happens later this year.

[Karen Roemer]

Re: BTK MatLab tools for C3D files not working

Hi James,

thanks a million! It works like a charm.
It's great to hear, that this step will become part of the new OpenSim release... I also can't wait for the Mac version, they are working on right now!

Thanks

Karen

[mohamad reza kharazi]

Re: BTK MatLab tools for C3D files not working

Hi

same problem here, the download link is not working. can you please upload the btk library somewhere else so i can download it

Hi, Karen-

I saw your post and I have Matlab 2018 on a Mac with the BTK source, so I recompiled the Mex functions as a static library. It works on my local system but I don't have a secondary Mac to test the libraries on. Download the library here and put it on your Matlab path. If that doesn't work, it is relatively easy to compile locally. BTK is no longer maintained by the creator so it may be worth knowing how to compile from source.

BTK has been forked into OpenSim, so there will be an easy Matlab method for reading c3d files when the next OpenSim release happens later this year.

[James Dunne]

Re: BTK MatLab tools for C3D files not working

Below is a link to download the binaries. It will be available for a week.

https://www.dropbox.com/s/ky2kzj941m70dbi/btk_Matlab2018_MacOS.zip?dl=0

[mohamad reza kharazi]

Re: BTK MatLab tools for C3D files not working

Thank you so much, really appreciate it. Do you have any suggestion for cd3 read and write in python 3 ?

[Edmund Cramp]

Re: BTK MatLab tools for C3D files not working

Below is a link to download the binaries. It will be available for a week.
https://www.dropbox.com/s/ky2kzj941m...MacOS.zip?dl=0

Thank you James, I have downloaded the zip file and re-posted it to the c3d web site (www.c3d.org) applications page so that it will be permanently available.

[James Dunne]

Re: BTK MatLab tools for C3D files not working

Thank you James, I have downloaded the zip file and re-posted it to the c3d web site (www.c3d.org) applications page so that it will be permanently available.

Thanks, Ed! On the application page, I would suggest noting that this was compiled using Matlab 2018a. I suspect that the binaries are only valid for the version of Matlab that they are built with.

Thanks!

[Patrick Mai]

Re: BTK MatLab tools for C3D files not working

Thanks, Ed! On the application page, I would suggest noting that this was compiled using Matlab 2018a. I suspect that the binaries are only valid for the version of Matlab that they are built with.

Thanks!

Hi, can you reupload the files, since the link is broken also at the c3d website

Thank you

[James Dunne]

Re: BTK MatLab tools for C3D files not working

The BTK binary for Mac and Matlab2018 is on the c3d.org site, here.

[Farhad Tabatabai Ghomsheh]

Re: BTK MatLab tools for C3D files not working

Hi Adam,

I am using 64 bit version for both (MatLab and BTK). I think that the BTK tools need to be re-compiled to work with the newest MatLab version. The newest toolbox on the BTK web-site is from 2014 and my issues started with updating MatLab to 2018a.

Karen

Can you send me a better solution?

[Edmund Cramp]

Re: BTK MatLab tools for C3D files not working

The BTK web site is here - http://biomechanical-toolkit.github.io/ - unfortunately it seems that support for the Biomechanics Tool Kit (BTK) has ceased, I have not seen any updates or responses to BTK questions in a while and given the problems that users appear to be having maybe I should remove it from the C3D web site? I would welcome any comments for or against this. Initially the BTK development appeared to be moving to http://www.openma.org/ but unfortunately the web site has not been updated in a while. Note that the free MOKKA C3D viewer application written with BTK is fully functional and is available from the C3D web site for 32/64-bit installations.

If you are looking for an alternative solution, we wrote the C3Dserver originally to give users the ability to access C3D files with only a minimum of understanding of the file format and application programming. A few years later BTK was written with our cooperation as an open source student project based on the C3Dserver. The C3Dserver is still available and can be downloaded and can be installed on 32/64-bit Windows systems from XP through Windows 10 and should be usable with Matlab. The free version is completely functional and not crippled in any way other than being faster if a license is purchased.