When calculating the cavity factor, it is possible for the relative
distance of all traversed connected vertices to be zero. This results in
a division by zero which does not get clamped correctly to the expected
[0.0, 1.0] bounds. Prior to 4.2, this would have had no effect, as the
processing of this vertex would be have been skipped entirely. Due to
changes during the brush refactor, this flaw in the existing code was
exposed.
Pull Request: https://projects.blender.org/blender/blender/pulls/140168
47523a4192