DWG refers to both a technology environment and. DWG files are basically CAD (Computer Aided Design) drawings consisting of vector image data and metadata written with binary coding. AutoCAD library of DWG models, free download high quality CAD Blocks. DWG (from drawing) is a proprietary binary file format used for storing two- and three- dimensional design data and metadata. DWG file extension is used to store files in DWG format. Step # 2 - Open your DWG file with “Draftsight” Now open “Draftsight”.