| Feature: Features modify the shape and appearance of the associated host element. Features in EM11 are further specialized based on its type. Features are Bolt Hole, Slot Hole, Opening, Cope, and Skewed End. A Feature has their own geometry representation and subtract its geometry from the shape of the master element through Voids Element (IfcRelVoidsElement). Features should not and cannot directly manipulate geometry of the host element using Boolean Operation (IfcBooleanResult) or Boundary Representation. |