Hi Bruce:

Thanks! I tried on a previous .tri file, and got the same answer. But when I tried a surface file from "save surface" in TkSurfer, it looks weird, and the total vertex number is not 163842, which is the standart in ic7.tri. Furthermore, it seems that we can only generate half brain surface everytime. That might be the reason that caused the strange result.

Would you please give me some advice? regarding how to generate a whole

brain surface file with the same amount vertex of ic7?

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Thanks a lot!

Tao

Bruce Fischl wrote:

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actually, you can just use the surfaces ico[34567].tr (7 is the

highest res). That is, use the topology from them, but copy the vertex positions from the average surface. I think Matti (ccd) has done this.

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cheers, Bruce

On Wed, 9 Mar 2005, Tao Song wrote:

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Hi Bruce:

Thanks for your quick reply. Actually, I can get a .tri file by save

surface as ... , then use mris_convert, and can read it. It is a very very high resolution tessellation of the brain, which looks similar as the result in TkSurfer, except color. And the coordinate system is already RAS. Is this the ICO surfaces (I checked wideman-one webpage, seems that both ICO and TRI are triangular surfaces)? Then if we want to choose first n points, (I suppose that you talk about n vertices), I have to get rid off the faces that include vertices other than the selected n vertices. I wonder if my understanding is correct? I tried it on surface generate by ""save surface as", there are large holes in the mesh. I also tried it on mris_converted rh.pial and lh.pial, I wonder do I need to combine those two together, to obtain a whole brain?

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Thanks Again!

Bruce Fischl wrote:

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the decimation code only finds equally spaced points, I don't think

it generates a tesselation. One way to downsample is to map onto on of the ico surfaces, then pick the first n points, where n is one of the downsampled icosahedra. Otherwise, I think there are other people who have written surface downsampling packages.

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cheers, Bruce

On Wed, 9 Mar 2005 tao@ucsd.edu wrote:

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Hi:

I am trying to generate a down sampled tessellation file from inflated pial in TkSurfer. I used write decimation in tool->surface menu,

and can

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find vertices. How can I fill the boundary of those points, and

save the

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vertices and faces, so that I can get a new .tri file?

Thanks a lot! _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer