Fluent format files may have the following extensions:
These files have exactly the same format internally, but can be written in text or binary form. STAR-CCM+ automatically recognizes a file as being binary or text and imports it without further action required.
You should note however that only mesh data is imported and boundary types are inferred from the boundary names. Any unrecognized types will be interpreted as walls. Therefore, any solution parameters or boundary conditions originally contained in Fluent must be re-defined in STAR-CCM+.