3D printing complex shapes is hard; the additive nature of most 3D printing means that the printer has to create sprues (struts that support parts of the structure during printing, which have to be removed later), or add in material that can be dissolved in a solvent bath after main production.
Researchers from MIT Media Lab's Mediated Matter lab have published a paper detailing a novel technique for 3D printing arbitrarily complex shapes by embedding them in a clear plastic matrix, like an insect trapped in clear amber.
The technique allows for 3D visualizations of otherwise unrepresentable forms, but it also just produces plain-old gorgeous artifacts. I'd love to see what a 3D printing sculptor like Bathsheba Grossman would do with this technique.
These floating dots that form the 3D object trapped inside the transparent material are called voxels. Voxels are just points in 3D space, little dots that result from the division of an object into a 3D array. Each little dot that forms a volume has assigned three coordinates (X, Y, and Z), which place the dot in a 3D space. The process is similar to traditional 2D color printing. But instead of printing on a piece of paper, you're printing out layers that get stacked on top of each other. When it's done, you get a full-color, 3D-printed model encapsulated in a clear block, like a Jurassic bug forever trapped in amber.
The technique allows you to create photorealistic 3D representations of anything you can imagine–imagine the face of someone captured in 3D with a stereo camera and printed this way, with every single hair and pore clearly defined. It also has significant potential in education and scientific visualization: While you can look at a 3D representation of data in virtual or augmented reality, looking at a real physical model is an experience that is hard to beat.
The gorgeous future of 3D printing [Jesus Diaz/Fast Company]
Making data matter: Voxel printing for the digital fabrication of data across scales and domains [Christoph Bader, Dominik Kolb, James C. Weaver, Sunanda Sharma, Ahmed Hosny, João Costa and Neri Oxman/Science Advances]
(via Beyond the Beyond)