Have you ever had dreams about building a robot？Or putting together a spaceship？Or even seeing your face made out of chocolate？If you have a 3-D printer，your dream will come true．

    All the users have to design an object on the computer and choose a material to print．The printers print in hundreds of different materials including glass，sugar and even skin！When the user presses“print”，the 3-D printer spreads the material layer(层)and like magic the object is produced．

    The first 3-D printer was invented in 1986 by an American．Charles Hull．But 3-D printing has only become cheap enough recently for most people to use．Designers now use 3-D printing to create unusual things．The Dutch artist Dirk Vander Kooj prints furniture made from old fridges．And doctors have used 3-D printing to print human body parts！The Telegraph reported((每日电讯报》in February that scientists from Cornell Medical College even printed a man-made ear．

    But like a lot of new technologies，if 3-D printing gets into the wrong hands，it Can be dangerous．In 2011 a group of four men in the US used 3-D printing to produce ATM skimmers(提款机盗刷器)．These were placed on an ATM and stole over $400，000 from users of the ATM．It is terrible to think that criminals like them might one day use a 3-D printer to print a gun．

    But for better or for worse，3-D printing has been put into use．In a few years，you'll probably be wondering how you could ever live without your 3-D printer！