Hi Tuomas
the patch face list will be a subset of the full one. Note that because faces can be excluded from the patch you can't just compare say the 5th faces in each - you have to look up the index (given in the patch file) and use that to find the corresponding face in the full surface file.
cheers Bruce
On Thu, 9 Feb 2012, Tuomas Tolvanen wrote:
Hi Bruce,
Thanks for clarifying this. Another question. When comparing lh.sphere and lh.white face lists they are exactly the same, which makes sense and only vertice's coordinates differs. Does this apply also for the face list of the flattened patch? Because I made quick check and most of the faces of the flattened patch equals for the faces of lh.white but there is still plenty of faces that do not match.. Or is this only a coincidence?
-Tuomas
On 06/02/12 16:51, Bruce Fischl wrote:
Hi Tuomas
yes, the format of the face list in the ascii file is:
<face index> <vertex index> <vertice index> <vertex index> . . .
where all the indices are 0-based, and the<vertex index> entries are the 3 vertices that make up that triangular face. Note that *only* the faces and vertices that have not been removed by cutting are in the patch file.
cheers Bruce
On Mon, 6 Feb 2012, Tuomas Tolvanen wrote:
Dear surfers,
Using [faces verts] = freesurfer_read_surf(surface) gives me the face list and vertices coordinates. I assume that using different surface (e.g. lh.white and lh.sphere) changes only the coordinates and the face list remains the same (?). What about with flattened patch? I converted the flattened patch to ascii and read it to Matlab. This is what I got:
First ten rows:
'#!ascii version of patch ./lh.orig. The 1st index is not a vertex number' '25720 50563' '1 vno=0' '6.217312 34.772942 0.000000' '2 vno=1' '6.013689 34.451294 0.000000' '3 vno=2' '5.807863 33.961815 0.000000' '4 vno=3' '6.546745 34.426727 0.000000' ... At somepoint the rows changes to this:
'0' '0 1 3 ' '1' '4 3 1 ' '2' '0 75 1 ' '3' '76 1 75 ' '4' '0 3 83 ' '5'It's obvious that every second row, starting from the 4th row, is the xyz-coordinates of the vertex on the flatmap. Is the latter part of the ascii data the face list? And if it is, are those indices referring to the original vertice indices?
Long story short: does the ascii data (of the flat patch) consist of the vertice coordinates and the face list in the same way as lh.white (with the exception that indices are reduced by one [1=0, 2=1...])?
-Tuomas
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