In 1546 Michelangelo produced the highly complex ovoid design for the pavement of the Campidoglio and began designing an upper storey for the Farnese Palace. In 1547 he took on the job of completing St Peters Basilica, begun to a design by Bramante, and with several intermediate designs by several architects. Michelangelo returned to Bramantes design, retaining the basic form and concepts by simplifying and strengthening the design to create a more dynamic and unified whole.[80] Although the late 16th-century engraving depicts the dome as having a hemispherical profile, the dome of Michelangelos model is somewhat ovoid and the final product, as completed by Giacomo della Porta is more so.[80]