A thin sheet is formed into a surface having compound curvature by vacuum forming the sheet against an array of support posts which have been adjusted to define the locus of the desired surface. A rigid frame is placed on the exposed back surface of the sheet and bonded thereto while the vacuum formed shape is maintained. Alternatively, a frame of beam members kerfed to make them compliant is placed on the back surface and bonded to the sheet which restores the structural integrity of the beams by briding the kerfs.