STL Import for AutoCAD is a plug-in for AutoCAD. This plug-in gives AutoCAD the ability to import geometric data from ASCII as well as binary Stereolithography (STL) files.The STL file format has become the Rapid Prototyping industry's standard data transmission format and is the format required to interact with stereolithography machines. Stereolithography files contain solids which are made up of 3 sided facets. STL Import for AutoCAD converts these facets into a single AutoCAD PolyFace Mesh entity and adds it to the contents of the currently opened AutoCAD drawing. This PolyFace Mesh is white in color and is placed in layer "0" of the AutoCAD drawing.STL Import for AutoCAD is very easy to use as it adds a new command to AutoCAD called "STLIN". The user has to simply type "STLIN" at the AutoCAD command prompt and select a STL file to import.