USD is a framework for interchange of 3D computer graphics data, created by Pixar. The framework focuses on collaboration, non-destructive editing, and enabling multiple views and opinions about graphics data.
A DWG file is a database of 2D or 3D drawings created with AutoCAD. It contains vector image data and metadata describing the contents of the file. DWG files are related to .DXF files, which are ASCII versions of DWG files.