.RFS File

File extension rfs is associated with RealFlow, a software tool for creating flawless large-and small-scale fluid and dynamics simulations, developed by Next Limit S.L.

A typical .rfs file contains scripts used in the program.

How to open:

Scripts usually work in their respective programs. At best you could open and edit it using any text editor.

How to convert:

It is unlikely that you can directly convert scripts to anything else.