model to stp conversion can be interpreted in several ways, often users just want to convert some 3D model to STP/STEP format, but for this you have to specify the exact 3D model to find eligible software.
As for specific .model files, these are from CATIA and in proprietary format, meaning rarely supported in 3rd party apps. Sometimes support for CATIA files can be added via plugins and there is always the option of dedicated 3D converters.
Updated: September 13, 2023