Hi Darren.
I agree that this should be straightforward.
The format for old (ico) can be found in libss/libtessa.* - this gives you
the tesselations. I'll be happy to modify the code so that the structures
such as old do not get deleted until the end.
let me know how you get on - feel free to email me directly for specific
advice on this.
Thanks, Steve.
On Fri, 2 Aug 2002, Darren Weber wrote:
>
> Hi Steve,
>
> the source code for BET that I have has the following lines 242:249,
>
> {
> object *old = &ico; /* start with icosohedral tessellation */
>
> tessa((int)TESSELATE_ORDER,&old); /* create tessellated triangles; level 5 gives 2562 points */
> pc=points_list(old,&v); /* convert triangles to vertex list */
> free(old); /* don't need triangular tessellation any more */
>
> /*printf("VERTICES %d\n",pc);*/
>
>
> Unfortunately, I do need the triangular tesselation :-)
>
> I have a simple matlab method for reading the output vertices from the
> .coo file (given the -x option to BET), but the .dat file is just the
> nearest neighbours of each vertex, not the tesselation. I've tried to
> tesselate these, but it's not a trivial process, especially when you
> want the tesselation to obey the right hand rule.
>
> Hence, it would be simpler to use the tesselation faces created by the
> &ico function. I am a little familiar with how this function works, as
> I adapted it for matlab. However, I'm not familiar with the libss
> version and how it is called from BET, so I would be grateful if you
> could assist me with a small modification to this code above? Rather
> than the printf that is commented out above, I would like a similar
> printf for the FACES from the old object, hence I would like to shift
> the free(old); command below the new printf for FACES. It is not clear
> to me how these are stored in the old object.
>
> Hopefully obtaining the FACES at this stage of BET is OK. It would
> assume that latter stages of BET do not significantly move the vertices
> off their original direction cosines and thereby modify the
> relationships between vertices so much as to make the triangular
> tesselation invalid.
>
> I hope this makes sense? I hope this is a fairly simple modification.
>
> Take care, Darren
>
>
>
>
>
> --
> Darren Weber, PhD Student
> Cognitive Neuroscience, School of Psychology
> Flinders University of SA, GPO Box 2100, Adelaide, SA 5001, Aust.
> Ph: (61 8) 8201 3889, Fax: (61 8) 8201 3877
> http://203.3.164.46/~dlw/homepages/index.html
>
>
Stephen M. Smith
Head of Image Analysis, FMRIB
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
