Flange wall features may be either swept or extruded.

A swept flange wall follows the trajectory formed by the chain of tangent attachment edges. You can sketch a cross section along the attachment edge and the wall sweeps along that edge. The attachment edge need not be linear and the adjacent surface need not have to be planar.

An extruded flange wall extends from one linear edge into space. You can sketch the side section of the wall and project it to a certain length in both directions.