PRC (Product Representation Compact) is a 3D file format that can be used to embed 3D data in a PDF file.
This highly compressed format facilitates the storage of different representations of a 3D model. For example, you can save only a visual representation that consists of polygons (a tessellation), or you can save the model's exact geometry (B-rep data). Varying levels of compression can be applied to the 3D CAD data when it is converted to the PRC format using Adobe Acrobat 3D.
AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange formal) is a CAD file format created by Autodesk for AutoCAD more compatible with other programs.
DXF was initially intended to represent exact copy of the data in the AutoCAD native format DWG (Drawing).
It can’t hurt if we mention that DXF coordinates come always without dimensions so the user needs to know the drawing unit or has to extract it from the textual comments in the sheets.