Hi. I was told to post this on the forums. Originally I made a bug report for it (http://developer.blender.org/T53132).
This describes a case where the Smooth brush, in Sculpt mode, collapses vertices on some open borders. Has this ever happened to you?
Smooth brush creates tension on some open borders
On some open borders of a mesh the Smooth brush seems to add tension instead of the expected relaxation.
Here’s the Smooth brush being used on such an open border:
This is the same mesh, with the open border selected in Edit mode and the Smooth Vertex operation being used a few times:
These are close-ups of the Smooth brush and Smooth Vertex scenarios above, respectively: