Abstract: A frame assembly supports a work surface of either flexible material or of sections of foldable and unfoldable relatively rigid material all so that the frame assembly and material may either be unfoldable and rigidized or folded into a compact package. The flexible frame assembly includes a pair of spaced poles and a number of hinged sections aligned so that the poles and material can be folded in sections. The poles rotate to permit either a frame folded disposition or a frame rigidized disposition. Embodiments include stretchers, screens and enclosures. The rigid material assembly provides a collapsible and rigidizable space spanning structure formed with a number of hinged sections of center supports and plates hingedly connected together to be either folded into a relatively compact device or unfolded and hingedly positioned to form rigidized space spanning structures.