A thin-sheet panel assembly. In one embodiment, a substantially rigid thin-sheet panel assembly having a non-rigid thin-sheet component includes the thin-sheet component which has selected plan area and shape, a backer having a plan shape and area substantially similar to the thin-sheet component, and plural riser elements of selected height and configuration each extending from the backer to distal ends connected to a reverse surface of the thin-sheet component, the riser elements being configured and disposed in an array which causes the assembly to have substantial rigidity in a selected direction in the thin-sheet component, and the thin-sheet panel assembly further includes a bar coupled to the backer and extending between at least one pair of adjacent riser elements of the plural riser elements.