TriplyAM is a free, open-source desktop application for engineers and designers working in additive manufacturing. It takes any 3D part — imported as STL or 3MF — and automatically generates internal lattice infill structures, replacing solid material with lightweight, printable geometry while preserving a solid outer shell. It supports four TPMS (Triply Periodic Minimal Surface) types including Gyroid, Schwarz P, Schwarz D, and Schoen I-WP, as well as two Voronoi strut network modes, giving users precise control over infill density, cell size, wall thickness, and strut geometry. The result exports as a print-ready 3MF file, ready to drop straight into any slicer. TriplyAM runs on Linux and Windows and is released under the MIT License — free to use for any purpose, personal or commercial.