According to the website, there are no Poser plugins available, just the following apps:

Autodesk 3D Studio Max

Autodesk Maya

Autodesk Softimage XSI

Blender

Maxon Cinema 4D

Sketchup

Modo

Remember, BR modeled the Arc in whatever modelling program he used, then exported to Octane for final rendering.  Or if the plugin does not exist, it can still use Wavefront OBJ formats.