Files with WMF extension represent Microsoft Windows Metafile (WMF) for storing vector as well as bitmap-format images data. To be more accurate, WMF belongs to the vector file format category of Graphics file formats that is device independent. Windows Graphical Device Interface (GDI) uses the functions stored in a WMF file to display an image on the screen
DXF, Drawing Interchange Format, or Drawing Exchange Format, is a tagged data representation of AutoCAD drawing file. Each element in the file has a prefix integer number called a group code. This group code actually represents the element that follows and indicates the meaning of a data element for a given object type. DXF makes it possible to represent almost all user-specified information in a drawing file.