Envelope surface

The envelope of a volume of any shape is called the sum of all surfaces bounding it . In contrast to the lateral surface of bodies of revolution, the lower and upper sides are also taken into account for the envelope surface. In contrast to the developable surface , the envelope surfaces also include surfaces that are curved twice.

In construction, the envelope surface describes the entirety of all heat transferring surfaces of a building against the outside air or the ground as well as adjacent low or unheated components.

In mechanical engineering, the envelope of a motor is the shape that describes a motor and all of its attachments. It is used, for example, when planning the engine compartments of a car body in CAD .