A system comprising a scanner to scan an ear and a processor to receive, from the scanner, a non-manifold three-dimensional (3D) digital surface model (DSM) scan data representative of a non-manifold 3D surface model of the auditory canal and the concha of the ear. The 3D surface model is an outer boundary surface for an earpiece appliance. The processor determines an extrema boundary located at a free edge of the 3D surface model; recognizes anatomical features including a cymba concha and auditory canal peak; modifies the 3D surface model relative to the anatomical features by creating a base boundary plane for the appliance, offset some distance from the extrema boundary; creates a closed volume within and between the outer boundary surface, the extrema boundary and the base boundary plane to form a solid 3D earpiece appliance; and causes a computer-aided manufacturing device to manufacture the solid 3D earpiece appliance.