Dear FS peeps,
 
 
I am trying to downsample a (white matter) surface with mri_surf2surf. I also want the output in .tri format.
 
First problem is that mri_surf2surf doesn't let me output in .tri format
 
mri_surf2surf --hemi lh --srcsubject subj1 --sval-xyz white --trgsubject subj1 --trgicoorder 4 --trgsurfval subj1_white_downsampled.tri --tfmt tri
 
gives me
 
ERROR: could not determine type of temp_surf_white.tri
 
(that happens with the 'tfmt' flag or not)
 
The command does work when the output is a .gii or .mgh file, but when I then try to convert those files to .tri format with mris_convert I get the error
 
ERROR: MRISread: cannot read surface data from file subj1_white_downsampled.gii!
 
...which is also the error I get when trying to load the file into freeview as a surface.
 
 
 
Any idea what I'm doing wrong here? If there is a better way to convert lh.white into a downsampled .tri file please do tell.
 
 
Thanks very much,
                                     john
 
 
 
(p.s. thanks to Dan, Doug, and Bruce for getting me to this point...)