So how, you may be wondering, does the apparent magic of3D printing actually work? Well, to a large extent, the pro-cesses  involved  are  no  more  than  a  logical  evolution  of  the2D  printing  technologies  already  in  use  in  a  great  manyoffices and homes.

Most  people  are  familiar  with  the  inkjet  or  laser  printersthat  produce  most  of  today’s  documents  or  photographs.These create text or images by controlling the placement ofink  or  toner  on  the  surface  of  a  piece  of  paper.  In  a  similarfashion, 3D printers manufacture objects by controlling theplacement  and  adhesion  of  successive  layers  of  a  ‘buildmaterial’ in 3D space.

To 3D print an object, a digital model first needs to exist ina computer. This may be fashioned by hand using a computeraided design (CAD) application, or some other variety of 3Dmodelling  software.  Alternatively,  a  digital  model  may  becreated  by  scanning  a  real  object  with  a  3D  scanner,  orperhaps by taking a scan of something and then tweaking itwith software tools. As we shall see in chapter 5, desktop andhandheld 3D scanners are now improving rapidly, with en-try-level models on sale for a few hundred dollars.