A filament for the 3D printer is made of thermoplastic and is melted for 3D printing in the 3D printer. After the melting process, the heated print head applies the viscous plastic thread layer by layer to a printing plate (hotbed) by means of so-called extrusion. The shape of the 3D object is determined by data from a CAD file (Computer-Aided Design), which is converted into movement commands for the printer during so-called "slicing". With common 3D printers such as Ultimaker, Prusa and Makerbot, it is possible for anyone to print 3D objects designed on the computer. But it is also possible to use the technology without a computer and 3D printer: With a 3D pen lined with short pieces of filament, you can simply "paint" objects in three-dimensional space. In this way, a 3D pen promotes three-dimensional thinking and gives room for creative ideas. Filaments for 3D printing are available in a large selection and in a wide variety of colors and materials. High-quality filaments are just as important as the right 3D printer. The most popular printer materials are PLA filament, PETG filament and ABS filament. They are usually offered on 1 kg rolls.