Semantic arguments aside as to whether this technique is legitimate “3D printing” or not, this method, developed by researchers at Disney, is definitely worth paying attention to. It’s actually a real ah-ha moment, such an obvious idea, you wonder why this isn’t in common use already.
The idea is quite simple. You first create a digital image where software works to deform the image to compensate for its eventual application onto a three-dimensional surface. The pre-deformed image is printed onto a plastic stock which is then fed into a vacuum forming machine. The thermoforming process creates a full-color 3D plastic copy over a previously-printed mold.
In a white paper [PDF] published to by Disney Research, the authors explain the graphic computation/software side of things:
On the algorithmic side, we propose a software simulation that creates the necessary pre-distorted texture image to be printed on the plastic, thereby ensuring that once the sheet is deformed, each pixel of the texture lands in its correct location on the 3D shape. The material model and the parameters for the simulation are automatically extracted by scanning and analyzing a single calibration object made with our forming pipeline. On the hardware side, we propose an effective method to produce a gypsum mold using a 3D printer with polylactic acid (PLA) filament, and a simple way to print texture on a plastic sheet using a standard color laser printer and transfer paper. The individual hardware components in our pipeline can be easily substituted thanks to our simple calibration procedure.
The paper concludes:
We proposed a new digital fabrication method to manufacture objects with a high resolution texture using thermoforming. Our solution relies on common hardware available in many digital fabrication labs and produces objects with a surface quality greatly superior to competing techniques. We believe computational thermoforming will have a significant impact in the fabrication community thanks to its low cost, low hardware requirements, high fabrication speed and quality, and that it has the potential to be a valuable tool for industries to quickly experiment with different thermoformed product designs.
You can read the complete white paper here.