MATLAB changing parameter data type/ezc3dWrite won't write integer parameter

[tishyaw]

When I read a C3D in MATLAB using ezc3dRead and then write it (without changes) using ezc3dWrite, parameters in the TRIAL group such as ACTUAL_START_FIELD, ACTUAL_END_FIELD, X_DIRECTION, Y_DIRECTION, Z_DIRECTION change from integers (as written by Vicon) to real numbers. This causes a problem reading the C3D in some programs. In the MATLAB structure, the parameter data are type double and if I try to change them to integer (uint16) or another type ezc3dWrite gives the error: "Error using ezc3dWrite. Unrecognized type for parameter.TRIAL.ACTUAL_START_FIELD." Is it possible to get these written out as integer (unsigned int16)?

[pariterre]

Hello!
This is one of the most annoying problem I faced when coding ezc3d, and I just gave up. The problem is that Matlab (and Python as well actually), won't differentiate integers and floats. When I prepare a value to be written, for instance the number 2, it automatically reads it as a float because 2 and 2.0 are actually the same thing. This automatically call the routine that store float (instead of ints).

Due to the sloppy implementions of c3d formatting by company, I cannot simply look at the original type (sometimes they get it wrong, and sometimes they are against the standard as prescribed by the official doc).

That said, ACTUAL_START_FIELD and ACTUAL_END_FIELD are fields that I don't recognize and I suspect they mimic the START_FIELD which is a mandatory element. Maybe it is from a new software?

[tishyaw]

I believe ACTUAL_START_FIELD and ACTUAL_END_FIELD are written by Vicon. Is there a way I can change the fields to uint16 and write out the C3D? I can change it in the data structure, but then ezc3dWrite fails with the error in the original post. ezc3dWrite seems to only work if the type is double.

[pariterre]

Hi @tishyaw !

I could not address your comment earlier, but in the mean time, I forced the parameters ACTUAL_START_FIELD and ACTUAL_END_FIELD to be of type INTs if the MANUFACTURER is VICON. Which should solve the problem
(See pull request #390 )

I will shortly release a version that includes this feature!

Thanks for your patience.

Please comment or close this issue when you have tested :)