Hey Gamer08, the quick answer is that you don’t. If I remember right, and also keep in mind that I’m talking about the module as it is in 4.7, the entire module that defines FRawMesh is designed to work only in the editor. If you click the API link in my answer take notice that the the header file path starts in the developer directory. Here’s some reading material about what that means.
See how in my example code I dump vertex information into a curve? Well, that’s so I can store the information when I select a mesh in the editor and then I access the curve in game when I want the data. Again, not sure if a curve is the best storage device for that, it probably isn’t. If you need to select and load information on a mesh that you didn’t store info about in the editor then I would recommend writing a file parser.