A method and apparatus for making a three-dimensional object by solidifying a photohardenable material are shown and described. A photohardening inhibitor is admitted into a surface of a photohardenable material through a flexible film to create a “non-solidification zone” where little or no solidification occurs. The non-solidification zone prevents the exposed surface of the photohardenable material from solidifying in contact with the film. The inhibitor tends to cause the film to deform along the build axis, thereby creating a non-planar interface between the photohardenable material and the film, which distorts the resulting three-dimensional object. An apparatus is provided to stabilize the flexible film and eliminate or minimize such deformation.