How to mark faces of a hole in Tetgen?

Question

Using a .poly file, I created models with holes in them. I would like to mark/identify the faces bounding these holes. Is there a way? Maybe using regions?

Answer 1

You can do it using the [boundary marker] attribute. See the example below.

Example (with arbitrary numbers):

342 3 0 1
- - -
1 0.312500 0.000000 0.000000 1
2 0.304126 0.000000 0.031250 1
 . . .
303 -0.004873 -0.259999 -0.017013 2
304 -0.008291 -0.267013 -0.008944 2
 . . .

where the format is:

[index] [x_coordinate] [y_coordinate] [z_cordinate] [boundary marker]

So now, you have marked vertices. So in the next part of the .poly file, we'll specify faces.

676 1
- - -
1 0 1
3 15 16 13
1 0 1
3 13 16 17
  . . .
1 0 2
3 304 303 335
1 0 2
3 303 309 335

where the format is:

[# of polygons] [# of holes] [boundary marker]
[# of corners] [corner 1] [corner 2] ... [corner #]