Geometry Mode allows the user to performa variety of modeling operations on the BSP brushes of their level. In this video we overview the UI of the Geometry Mode window.
Extrusions are one of the most basic types of modeling operations. In this video we show how the extrude modeifier works within Geometry Mode.
Brush Clipping allows for brushes to be chopped up, as if with a cutting laser. This video shows how to clip your brushes.
The Pen modifier allows the user to create brushes and brush shapes by drawing out a simple outline of an object.
Lathing allows for a way to revolve a brush shape a certain number of degrees to create various brush forms.
The Active Modifiers in Geometry Mode allow the user to perform a variety of one-click functions on the geometry of their brushes.