STL Import for AutoCAD is a Stereolithography (.stl) file import add-in for AutoCAD. This plug-in gives AutoCAD the ability to import geometric data from ASCII and Binary STL files. STL Import for AutoCAD reads polygon mesh data stored in STL files and imports it into AutoCAD. A polygon mesh in a STL file is comprised of a set of triangular faces. STL Import for AutoCAD recreates the STL model data inside the active AutoCAD drawing.