NOVELTY - The unit (100) has a continuous layer with two sets of main-faces (110, 120) defining respective surfaces and extending between the surfaces. The main-faces are connected by respective side-faces (130, 140) along a direction, where a thickness of the structural unit given by a distance between the surfaces is larger than a thickness of the continuous layer. One set of main-faces is connected by bridge-faces (170), and the bridge-faces are connected to another set of main-faces by bridge-side-faces (175) along a direction that is different from the former direction.    USE - Three-dimensional structural unit for use in a composite unit, modular building system for a house, open lattice structure, structural beam, wall-unit and damping unit (all claimed). Can also be used as anodes and cathodes in a battery cell configuration, for transportation and/or protection devices for substances contained in its channels and void spaces, in military, industrial and commercial components, for aircraft, aerospace applications, automobiles, for building structures, modular house, retaining wall, stairs, concrete reinforcement, glass reinforcement, floor coverings, for shock absorbing unit such as floor mats, shoe soles, tires, harbor shock absorbing mechanism, for curved surface structure and for reinforcing materials for bridge decks, fuselages, pipes, pressure vessels.    ADVANTAGE - The utilization of the continuous layer enables the structural unit to have high rigidity in many directions and a high strength to weight ratio.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a composite unit comprising a structural unit and a face-sheet    (2) a modular building system comprising a structural unit and a mount unit    (3) an open lattice structure comprising two structural units    (4) a structural beam comprising a structural unit and two flanges    (5) a wall-unit comprising a structural unit and a chord unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a structural unit.    Three-dimensional structural unit (100)    Main-faces (110, 120)    Side-faces (130, 140)    Bridge-faces (170)    Bridge-side-faces (175)