What is 3D printing? A 3D printer uses an "additive manufacturing process" (which means an object is built up a layer at a time). Most 3D printers have a single extruder head, which means if you want to use multiple colors, you may have to print your object in sections, and even then you’ll be limited in how the object can be colored. This is why the most common 3D examples are objects like a blue-hued plastic Yoda -- single color printers are most common.