DWG and DXF are two of the most widely used graphics formats in the construction and engineering industry. They are usually created via AutoCAD, the popular software for drafting 2D and 3D computer-aided design projects, and they store large layered files with detailed building plans, maps, model designs etc. DXF represents the interchange version of DWG and both formats are scalable vectors storing images as polygons.
Are you an architect or a designer? Then DWG (Drawing) is probably a format you use very often. Highly popular in the construction and engineering business, DWG files store sketches and building projects, maps and geometric data. They represent the native format of AutoCAD, which is probably the best known computer-aided design software.
One of the advantages of using the DWG format is the possibility to attach referenced drawings or XREFs. These are linked to the main drawing, but the best part is they are not actually inserted into it, which means they do not add to its file size. However, when an editing or update is made to the xref drawing, it also appears in the main DWG file.