[Gmsh] How does GMSH know which side of a surface is the INside?

[John Villarrubia]

Hello everyone,

I note in the documentation that line loops are oriented, and in writing 
a script to creates a .geo file I was careful to orient all my line 
loops clockwise when viewed from inside. However, I have since noticed 
that when I define a simple structure (e.g., a cube) using the GMSH GUI, 
the .geo file it produces has some of the sides clockwise and some 
counter-clockwise.

That being the case, how does GMSH know which side of a face is the 
inside of my cube and which the outside?

John