Hi everyone,
I need to create the vector normal to the surface at each "white" vertex. I would like to end up with 7 fields in each entry:
1 Vertex number 2-4 RAS coordinates 5-7 RAS components of the normal vector pointed from ctx --> wm
mri_annotation2label gets me the first 4. I just don't want to reinvent the wheel getting the normal. If there's a way to get freesurfer to kick out the normals, that would be best. Here are naïve questions that arise out of this problem:
1. Is there a simple way to identify which vertices are "nearest neighbors" other than measuring and sorting the distances between each and all the others i.e. which ones form a triangle? I understand to use the normalized average of the 6 triangles which include the vertex.
2. Is there a simple way to identify the order of the sides of each triangle so that their cross product is ordered correctly to produce ctx --> wm?
Thanks for your help with this.
Don