Owning a Makerbot 3D printer means being able to make anything you want at a push of a button, right? 3D printer owners quickly find that while 3D printers have no end of things they can produce, they also are not without their limitations. Designing an object without 3D printing in mind will result in a failed print that more resembles a bird nest or a bowl of spaghetti.
Making a 3D printable object requires learning a few rules, some careful planning, and design. But once you know the rules the results can be astounding. 3D printers can even produce things with ease that traditional manufacturing cannot, for example, objects with complex internal geometry that machining cannot touch.
There are many places online such as Makerbot's own Thingiverse that hosts a daily growing library of printable objects. Printing out other people's designs is all well and good for a while, but the most exciting part about 3D printing is that it can produce your designs and models. Eventually, learning how to model for 3D printing is a must.
Can you learn 3D modeling? If you've ever won a round of Pictionary you've got all the artistic skill it takes to get started. If you've ever gotten past level 1 on Tetris then you've got spatial reasoning. If you've ever played with modeling clay then you know all about designing in three dimensions.