[Freesurfer] mesh decimation

I am trying to reduce the number of vertices in a freesurfer mesh. I am having some difficulty when I go through matlab using the 'reducepatch' command : some of the surface normals end up being scrambled resulting in strange transparent holes in the mesh. I wonder if there is some command-line routine that will directly take, say, rh.pial , decimate it and write out another mesh, say, rh.pial_dec

I see that tksurfer has a write_decimation option and this works in that it generates a file but I don't know what format the output is. It doesn't seem to be a valid surface file and tksurfer will crash when I try to load it.

Thanks in advance for your help

Alex

A.R. Wade Ph.D. Associate Scientist Brain Imaging Center The Smith-Kettlewell Eye Research Institute 2318 Fillmore Street San Francisco, CA 94115

tel. 415 345 2083 fax. 309 416 6533