This technical report will detail a process for creating a 3D model of Charles Perry’s sculpture “Duality.” The sculpture can be described as four ribbons whose ends are connected by two 4-way junctions. By plotting points on a picture of the sculpture, parametric rays can be created and manually adjusted to give depth to said points and approximate the sculpture’s shape in 3D space. Inserting multiple pictures with different viewpoints into the CAD environment provides more conditions to guide the approximation. “Duality” also has three mutually orthogonal symmetry axes. This is exploited by only modeling one quarter of the sculpture and then fitting it together with three of its copies, each of which are rotated by 180° around one of the three symmetry axes.