How do I interpret the following description of “physical distance” between mesh faces as described in the following paper; quote:

The second part of the formula measures the “physical” distance. It is the sum of the distances between the

centers of massof the two faces and the midpoint of their common edge.

On page 3 in this paper:

https://webee.technion.ac.il/~ayellet/Ps/ShlafmanTalKatz.pdf

It talks about “center of mass”. Is that the same location as the centroid? If so I interpret the Physical distance something like following, adding the distances a, b and c together:

Does this seem to be a correct interpretation?

**Edit**: Or… do they mean only a + b?

// Rolf