Used deposition modeling, or FDM for short, is a material extrusion method of additive manufacturing where materials are extruded through a nozzle and joined together to create 3D objects. In particular, the "standard" FDM process distinguishes itself from other material extrusion techniques, such as concrete and food 3D printing, by using thermoplastics as feedstock materials, usually in the forms of filaments or pellets. A typical FDM 3D printer, therefore, takes a polymer-based filament and forces it through a heated nozzle, which melts the material and deposits it in 2D layers on the build platform. While still warm, these layers fuse with each other to eventually create a three-dimensional part. Generally accepted as the simplest way to 3D print stuff, FDM is accessible, reasonably efficient, and widely popular. FDM printers dominate the 3D printing market, being remarkably more straightforward than resin 3D printing and massively cheaper than powder-based methods, such as selective laser sintering (SLS). In this article, we'll explore this acclaimed 3D printing process, going into detail about its inner workings, material possibilities, and much more. First, let's find out how it became so popular among makers and hobbyists.