When it comes to graphics and displays, the term "3D" can have several different meanings. Super Mario 64 had 3D graphics, in the sense that players could move Mario in three dimensions. But players' eyes still saw a 2D image. Modern virtual reality headsets produce visuals that users interpret as 3D, but those users are really looking at two 2D screens. True 3D graphics are difficult to display, because you would have to produce illumination at every coordinate in 3D space. Volumetric displays are as good as it gets right now and Madaeon's VVD DIY 3D volumetric display is capable of generating very impressive results.
Real-world volumetric displays today come in two varieties: static volume and swept-volume. The former works without any moving parts in the volume where graphics display. One way to achieve that feat is by projecting a laser focused on a point in 3D space to create a glowing ball of plasma. Swept-volume displays rely on a moving planar display to take advantage of persistence of vision. The most well-known example of a swept-volume display is the proprietary — and expensive — Voxon Photonics VX1. Madaeon's VVD is also a swept-volume display, but you can build this device yourself if you have the skill.
Persistence of vision is an optical illusion that all sighted humans experience. It is what tricks us into seeing a series of still images as moving objects when we watch a video. 24 frames per second (FPS) is the standard for films and that is enough for us to interpret motion. A swept-volume display has to achieve similar results, but at every "pixel" of resolution in the Z axis. To put this into perspective, if you wanted a 600x600x600 24 FPS resolution volumetric display, you would need to move a 2D 600x600 display up and down and at 14,400 FPS—24 FPS for each of the 600 Z axis pixels.
LCD refresh rates top out at around 480 Hz, which is why this device relies on laser projection. Instead of moving an entire display up and down, this device uses stepper motors to move a thin panel of translucent film in the Z axis. A Texas Instruments DLP Light Crafter projects laser graphics onto that film from below. It can can produce 608x684 monochrome images at 4,000 Hz. That isn't fast enough to create moving 3D images as smooth as a 24 FPS movie, but it is plenty for still 3D images. An UDOO X86 single-board computer controls the projector.
The display's frame laser-cut metal. Users can load 3D models (in common formats like .STL) from a USB drive or any other storage source. Madaeon's software automatically translates those models into a series of images for the projector to work with. A conventional LCD screen on the front of the device lets users see settings and select models. This is not a project for the faint of heart, but the parts should cost less than $1,000. That is far more affordable than the Voxon VX1's $9,800 price tag.