We present ByzantineCAD, a feature-based parametric CAD system for designing pierced Byzantine jewellery. ByzantineCAD is an automated system where jewellery is designed according to the values of parameters and constraints that are determined by the end-user. In this paper, we introduce an approach to reproducing traditional pierced Byzantine jewellery using pierced voxels ("poxels"). Poxels are voxels with specific attributes and properties that are appropriately combined to create large complex pierced designs. We also present a scaling algorithm for enlarging pierced designs without altering the size of the poxels used to construct them and an algorithm for engraving arbitrary images in pierced jewellery.