I am reading the 1987 paper on Geodesics on polyhedra and I am confused on something.
The paper states:
If $I1==NIL$, the channel is simply that part of $f’$ to the left of $\beta_2c_2$; and if $I2==NIL$, the channel is that to the right of $\beta_1c_1$.
"Right" and "left" are pretty meaningless terms. So far I have at least 3 interpretations of the areas they mean:
Orthogonal projection onto the opposite edge:
Or the entire face.
All of these can be thought of as "the left" of the red segment. Which one is the one the authors meant?