Hi Yasheng,

hmmm, there is triangle/triangle intersection code that is supposed to prevent this from happening. Does this happen if you use the native (binary) format? How many faces intersect?

Bruce

On Mon, 8 Mar 2010 yasheng_chen@med.unc.edu wrote:

Hi all,

I am using tetgen to construct a tetrahedral mesh with the extracted pial

surface in subject 004 from the tutorial datasets.  But I got an error message from tetgen to say that some triangles are intersecting each other.  I am not sure whether anyone has found this before. The file I tested was 004/lh.pial.  I first transferred it to asc format with mris_convert, and then make a straightforward transfer to .off (used by tetgen and geomview).  I loaded the .off file with geomview and it looks right.  Then I run tetgen with the .off file and got an error message like below, which means that there are intersections among the facets.

Error:  Invalid PLC.   Two subfaces (219028, 5283, 5282) and (219054, 5300, 5283)   are found intersecting each other.   Hint:  Use -d switch to find all intersecting facets.

This is a little strange to me since the topology issue has been handled in the reconstructed surface, does any one have any clue?

Thank you very much!

Yasheng