Generally speaking, 3D models (such as the Parasolid .x_b files) can be exported as a common polygon files (.ply) with several CAD/3D modeling translation or conversion software.
Convert Parasolid model (binary) to Polygon graphics.
We have found 2 software records in our database eligible for .x_b to .ply file format conversion.
Microsoft Windows software - convert x_b to ply on Windows
A 3D CAD translation softwate
Convert from x_b file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned x_b to ply. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert x_b to ply on OS X
A Mac version of the popular 3D visualisation software