An implant includes: a sinusoidal container that includes: a plurality of projections; a plurality of troughs; and a plurality of smooth interfaces, wherein a smooth interface is interposed between a projection and an adjacent trough for the plurality of projections, troughs, and interfaces to provide a smooth continuous transition between adjacent projections and troughs. A process for making an implant includes: forming a sinusoidal container from a polymer, the sinusoidal container including: a plurality of projections; a plurality of troughs; and a plurality of smooth interfaces, wherein a smooth interface is interposed between a projection and an adjacent trough for the plurality of projections, troughs, and interfaces to provide a smooth continuous transition between adjacent projections and troughs; and providing a filling tube attached to the sinusoidal container to make the implant.