3D filaments (长丝) are the primary materials used in fused deposition modeling (FDM), one of the most popular methods of 3D 长丝 printing. These filaments are thermoplastic materials designed to be melted and extruded through a heated nozzle to build three-dimensional objects layer by layer. The variety of materials, ease of use, and ability to create customized designs make 3D filaments indispensable for industries, hobbyists, and researchers. This document explores the characteristics, applications, and advantages of 3D filaments, alongside key considerations for selecting the right filament for your needs.