Printed Optics: 3D Printing of Embedded Optical Elements for Interactive Devices, a paper from Disney researchers in Pittsburgh, details a set of toymaking techniques involving 3D printers. Some of them (like "a bug-like figure with glowing eyes that display different graphics") are intriguing in the extreme. I like the way they're thinking about 3D printed micro-channels as a means of moving light around within a solid toy. Here's the BBC's summary:
One application involved the creation of air pockets in the shape of thin hollow tubes of various lengths which were arranged to resemble the shape of a cartoon heart inside an animal-shaped figurine.
When illuminated from below using a light emitting-diode (LED) the tubes looked as if lots of tiny lights had been built into the toy and programmed to shine in sequence to resemble a beating heart.
Another example involved creating "light pipes" as a 3D-printed alternative to optical fibre.
The engineers said the pipes could be easily shaped to fit a toy's specific form, with joints placed at specific places allowing them to be linked to other light pipes. They said this would have been much harder to achieve with traditional fibre.