Write a c3d file using the C++ ezc3d library.
Details
This function takes an c3d object in R and writes it to a c3d file. The function creates a new c3d file from scratch and inserts all point data, analog data and parameters in the file. Note that the resulting file will show minor discrepancies compared to the original file (e.g., in terms of file structure). During import and export minor rounding errors can occur.
Force platform data is exported by writing the analog channels with raw force
data and the corresponding parameters of the FORCE_PLATFORM group for
processing. This means that in the current version, modifications to the
processed force platform data (obj$forceplatform) will not be exported.
Make modifications to the analog channels holding the raw data instead. If
you delete analog channels in your data, make sure that
obj$parameters$FORCE_PLATFORM$CHANNEL still points to the correct indices.
The header parameters of the c3d object will not be exported but recreated based on the parameter section. If you want to change the header you should change the appropriate parameters instead.
Be cautious when writing a modified c3d object to an c3d file, as internal
inconsistencies may lead to corrupt files. c3d_write() and the underlying
ezc3d function perform some basic checks but may fail if, for example,
parameters and data are inconsistent. You can use the helper function
c3d_setdata() for modifying point or analog data of a c3d object. Larger
modifications may requires expert knowledge of the c3d file structure and
parameters.
Examples
# read an example file
d <- c3d_read(c3d_example())
# create a temporary file
tmp <- tempfile()
on.exit(unlink(tmp))
# write c3d file
c3d_write(d, tmp)