[I/O]3 (Input/Output Cubed) is the next step in 3D modeling technology. Analogous to a drawing tablet, it aims to allow intuitive manipulation of virtual 3D objects on the computer, as well as display a volumetric image of those objects. User hand gestures control virtual object functions, like creation, translation, rotation, and scaling, as well as control functions, like saving a copy of the virtual model or undoing or redoing a change made on the model. This model will then be displayed on a volumetric display, allowing the user to visually examine their model as if it were a CNC machined or 3D printed before consuming any physical material. The volumetric display is a true, 3D representation of the virtual model utilizing persistence-of-vision, free of the characteristic distortions and limitations of common stereoscopic 3D displays. Combined with simple 3D modeling software, the hand-gesture tracking and true-3D volumetric display of [I/O]3 will provide users with a complete toolset to create, modify and save virtual 3D models intuitively, all while being able to view their creation as if it were a tangible object, without the time and material cost of physically building their model.