Knife
What is it about?
This page covers the Knife brush for sculpting in Cinema 4D. It pulls vertices together along the stroke and can lower them at the same time — producing sharp cuts, creases and incision-like details.
See Pinch for additional effects.
The Knife brush pulls the mesh vertices within its area of influence together or – with the Ctrl key pressed – lowers them.
Pulling together and lowering can be controlled separately using the brush's settings.
An overview of all available brushes can be found here: Brushes.