A sphere rendered in three different resolutions in MeshMixer When you increase the resolution, more triangles will be used, approximating the surfaces of the 3D model better, but also increasing the size of the STL file. The STL file format uses a series of linked triangles to recreate the surface geometry of a solid model. This article will teach you the basic steps you need to follow to correctly export your models for 3D printing. The 3D model is then converted into machine language (G-code) through a process called “slicing” and is ready to print. All modern CAD (Computer-Aided Design) software allows you to export their native file format into STL. It uses a series of triangles to represent the surfaces of a solid model. The STL (Standard Triangle Language) is the industry standard file type for 3D Printing.