Conversion from Intergraph Smart 3D to PRC is not supported yet :(

Intergraph Smart 3D, the most advanced plant design software offered in two decades, is Intergraph’s next generation, data-centric, rule-driven solution for streamlining engineering design processes while preserving existing data and making it more usable/re-usable. A fundamental component of Intergraph’s SmartPlant Enterprise, Smart 3D is a complementary, full-suite solution that provides all the capabilities needed to design a plant, and then keep it as built throughout its life cycle.

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.