BRL-CAD has a ProE-BRL export plugin for Pro/ENGINEER (i.e., ProE) providing a means to import geometry from ProE into BRL-CAD.
The plugin runs within Pro/E and exports geometry in polygonal format for use with BRL-CAD. Geometry is written into our ".asc" ASCII format which can be converted to our ".g" binary format with asc2g or or by sourcing the file into mged with the source command.
Note that the prescribed workflow with the ProE-BRL converter is a fundamentally lossy process that changes the representation format of the original geometry. The conversion to polygonal mesh geometry can introduce new overlaps on valid geometry or even fail outright (within Pro/E) if there are modeling errors. This time-intensive process is being deprecated by our active BREP/NURBS development effort.