Sculpt Tool

Being one of the major reasons to implement the painting tools, sculpt is also the most advanced tool of the current paint tools. Sculpt, AKA deform paint, is a tool, with which you can deform geometry by brush strokes. Reference coordinate systems are supported, and you can paint by normals. This makes it to a very powerful modeling tool.
Size, feather and depth are supported for stylus.
This tool is also available as a standalone modifier named "Sculpt".
Additionally, you can smoothen with this tool.