Parts having complexly curved, frequency selective surfaces can be manufactured with a high degree of precision using a three-dimensional conformal mask. The mask has a transparent substrate and a patterned opaque layer on the substrate. The layer may be patterned by laser ablation. Alternatively, the patterning of the opaque layer can be accomplished by applying a layer of photosensitive material over the opaque layer and then defining temporary and permanent areas thereof. The temporary areas of the photosensitive layer and the opaque layer are removed sequentially to define the transparent portions of the mask. Parts are made by intimately mating the mask and a part body to which a layer of metal and a layer of photosensitive material have been applied, and exposing the part to radiation through the mask. The exposed part is then chemically developed, the layer of metal is etched, and the remainder of the layer of photosensitive material is removed to complete the patterning of the part body surface. The mask is preferably made using a high precision laser etch system to sharply define the transparent portions of the mask and maximize the precision of the patterning on the subsequently made parts.