SnapCAD is an extension of the ideas that started with the UCube – a tangible interface to aid beginners in modeling and designing for 3D digital fabrication tools (like 3D printers). SnapCAD is essentially an interactive volumetric display – the pixels being LEDs on magnetic circuit boards that snap onto vertical towers in one of seven possible positions. The towers in turn can be placed and re-placed around a grid of 7×7 sockets. Thus, when an LED is placed on a seated tower a single (X,Y,Z) point in 3-space can be specified. These points are displayed in real-time in the SnapCAD software. The software can then be used to transform the set of input points using various algorithms and techniques – for example, by taking the convex hull of an input set, or finding the minimal spanning tree. These algorithms make 3D models that can then be exported to .STL format and printed on a 3D printer. By using different colors of LEDs, SnapCAD can be used to model multiple objects at once, and can even be used as a gaming platform for multi-user interactions (such as 3D tic-tac-toe).