Hi there,

In my understanding, mris_convert does not change any information (vertices coordinates and triangles) during converting, right? However, I observed odd thing as bellow,

Command I used:* mris_convert subjid/surf/lh.white subjid/surf/lh.white.stl*

I convert the white surface to .stl format, then load original white surface and .stl file in freeview, with subjid/mri/brainmask.mgz as volume underlay. The shape of lh.white.stl mesh looks the same as original one, but the position of lh.white.stl has totally been displaced. I attached a screenshot (yellow one is original white surface, red one is .stl format one).

I also used freesurfer_read_surf function to read the coordinates and the faces in matlab, then compare it to .stl coordinate, they are the same.

I need to use .stl format for my analysis outside freesurfer, then convert result back to freesurfer format. I am worried whether this odd thing cause any problems?

[image: Inline image 2]

PS, if it is fsaverage template surface, no position shift after format transform.

Many thanks if anyone help with this,

Ting