Physics Builder Design > Overview of the Physics Builder > Saving and Opening Custom Physics Interfaces

Saving and Opening Custom Physics Interfaces
Saving Physics Builder files works in the same way as ordinary model files (*.mph) except that it has the extension mphphb. Opening a file is also similar to opening MPH-files, but select Physics Builder File (*.mphphb) from the list of file types in the Open dialog box.
See The Physics Builder Manager for more information about organizing development files.
Saving COMSOL Files in the COMSOL Multiphysics Reference Manual