Computer Aided Design is used in industry for a number of purposes and may be performed in the traditional two-dimensional world or in the more revealing three-dimensional world. For example, the floor layout of a manufacturing plant might be made from a bird's eye view perspective, which might be best served with a 2-D plan view. Or, the swing path of a curved door might be best modeled in 3-D so the opening and closing path can be viewed from many perspectives - to more clearly see potential interferences.