I designed a collection of rings with the parametric modeling software Grasshopper for Rhino. Each piece is created with an individual algorithm and thus has it's own unique design DNA.
One key advantage to working this way is being able to generate a wide range of sizes, without affecting the critical product dimensions. The most common approach to creating a custom-fit ring involves scaling the whole design inside of a slicer, which not only changes the inner diameter of the ring, but all of the other features including the wall thickness as well. This can quickly lead to undesirable results or imperfect prints. Parametric design solves this issue.
Each design comes in a full range of 22 sizes from Size 3 (14 mm) to Size 13.5 (22.6 mm), each with precise features, optimized for fit and printability. Many print on-demand services, such as Shapeways, can print these models in wax, which is then cast in any number of metals. This process is surprisingly inexpensive and the results are incredible. See the last image below, where my wife and I had our wedding rings printed in silver and gold-plated brass.
The full collection and each of the 3D models is available at the following link.