Drawing with 3D pens is a little like creating things out of thin air, isn’t it? You glide your hand and out appears your drawing just as you imagined. In fact, the most popular 3D print pen, “3D Doodler”, has a tagline that pretty much sums how it works: “It’s a pen that can draw in the air! Lift your imagination off the page!”. As Wired.com put it once, the “3D Doodler is for “anyone with a passion for making”.