Blender Git Loki

Dam brush: Initial implementation

The purpose of this brush is to create sharp edges without creasing or
pinching the geometry. It is useful when sculpting cloth wrinkles, hard
surface objects or small cavities.
To avoid artifacts, set the stroke spacing to a lower value than 10 and
enable symmetry feather. This affects performance, so I am not adding it
to the defaults for now.
It does not create new geometry in dyntopo, so you will need to create
the geometry with another tool or switch to the voxel remesher workflow.
I'm not quite happy with the deformation as it is now (maybe it is too
smooth). I also need to try the brush with different pen tablets to
properly calibrate the pressure.