Theatre Design & Technology - Winter 2012 - 13

Printed Queen Ann furniture,
1/2˝ scale, showing
segmentation possible with
curves in STL files.

The exhibit Tutankhamun and the Golden Age
of the Pharaohs in Discovery Times Square in
New York featured a mummy that was created
out of UV-cured resin by a high-resolution iMaterialise 3D printer. The 2009 fantasy/horror stopmotion film, Coraline, featured faces and other
3D printed parts. A press release by Object, the
company that partnered with the film-makers,
claimed that this was "the first use of 3D printed
replacement faces in a feature-length film." The
company went on to describe the benefits of using their technology. "The character of Coraline
had the potential to exhibit well over 208,000 facial expressions. By comparison, the main character
in the 1993 stop-motion film The Nightmare Before Christmas-by the same director-had but 800
possible expressions, and was considered a breakthrough in animation in its day."
The technology of 3D printing has come a long way from the layered-paper machine I saw back
in 1999. However, with prices for the equipment ranging from $10,000 to $100,000, high-end prototyping is still out of reach for most theatre organization. But there are less expensive options.
Four years ago, people began developing low-cost alternatives to the professional machines. The
trade-off in cost, however, was that they required a huge time commitment and a lot of knowledge of
electrical and mechanical engineering to keep them running. But the technology kept improving. In
2009, Makerbot Industries (makerbot.com) announced it was selling a kit for hobbyists to build their
own 3D printer for less than $1,000. I immediately bought one of their first kits. It seemed like I was
finally going to realize my science fiction dreams.

the technology
Hobbyist printer kits use Fused Disposition Modeling (FDM) to build up an object. This type of additive manufacturing uses heated plastic that is pushed out of an extruder moving in a pattern controlled by the computer. It is basically a computer-controlled hot glue gun, except that the extruded
plastic in these 3D printers is thinner than the lead of a mechanical pencil. As the pattern for one
layer is done, the extruder moves a notch higher and lays down more plastic on top of the previous
layer. It continues, layer by layer, to create the object. Each layer is a fraction of a millimeter. The
height of the layers is a defining factor in the resolution of the printer.
3D printers commonly work with computer files in the STL format. It's a file format native to
stereolithography CAD software developed by 3D Systems. STL files, which can be exported by many
of the standard modeling and CAD programs, describe the surface geometry of an object in triangulated facets. This technique is very versatile and can represent complex organic shapes like faces or
simpler geometric shapes. Increasing the resolution settings when exporting increases the number
of triangle segments, which produces smoother looking curves. The smoothness of curved surfaces
in the Z plane (height) is determined by the thickness of the plastic in each layer.
There are a couple of steps to follow to get your design ready for the 3D printer. After creating your 3D model on the computer, you must first save it to the STL file format. Then you need to
use a "slicing" program to calculate the path that the tool will use to build the object. This path is
described in the G-Code scripting language. The printer uses this very specific G-code to instruct its
motors to move the correct amount and push out the correct amount of plastic. It is not a good idea

theatre design

& technology

winter

2012

http://www.makerbot.com

Table of Contents for the Digital Edition of Theatre Design & Technology - Winter 2012