STP Format
STP files are mainly used to transfer 3D graphics between different CAD and CAM systems. Many manufacturers use an STP file to design and quote molds or manufactured parts.
NOTE: STP files may also use the less common extension .STEP.
DWG format
DWG file is an AutoCAD drawing database file. It stores metadata and drawings of 2D or 3D vector images that can be used in CAD programs.
DWG files are compatible with many 3D and CAD drawing programs, making it easy to transfer drawings between programs. However, because there are multiple versions of this format, some DWG viewers cannot open every type of DWG file.