Abstract: Shaped articles comprising a polymeric frame of uniform density having one or more substantially non-foamed skin layers over all, or only a part of, its surface are produced according to the disclosed method which includes forming a foamable mixture of a photopolymerizable ethylenically unsaturated material, such as vinyl acetate, acrylonitrile, unsaturated polyester resins or the like, and a foaming agent therefor in a mould, subjecting part or all of the surface of the mixture retained in the mould to radiation of a wavelength such that photopolymerization of the material occurs forming a non-foamed or non-foamable skin layer or layers. The thus treated foamable mixture is then foamed and the ethylenically unsaturated material in the foam is polymerized. Shaped articles so produced having an open shell structure are also disclosed.