Blimps, which have no internal structure, derive their shape entirely from the design and construction of their outer envelope. Semi-rigid airships have internal skeletons that provide structural support for internal and externally mounted hardware. The shape of a rigid airship is defined by an outer structural framework that is covered by a fabric skin.

In addition to the inflatable primitives, essentially any shape can be realized as an inflatable, but they require internal structures to constrain the inflation to achieve the desired shape.

nU-Boats are hydraulically inflated with a variety of liquids ranging from fresh water to various hydrocarbons or a liquid form of syntactic foam, which provide incompressible, depth-independent buoyancy.

A buoyancy engine like those typically found in undersea gliders is used to adjust the density of the platform to match that at the desired depth.

nU-Boats are a radical departure in the design, materials, construction and capabilities of Autonomous Underwater Vehicles (AUV).

Because inflation pressure is radial outward and equal in all directions a sphere, a torus or a cylinder are the inflatable primitives.