FixVTF is a data conversion program written by Snakez. It converts Episode 2 format materials (which allow up to 1024x1024 size now) to the previous, Episode 1 format. Hammer uses Episode 1 format materials, models and maps until the official release of the Orange Box on 10 October, 2007. Another program by the same developer is called FixBSP, which converts maps into Episode 1 format. As to date, there are no programs out to converts models. Episode 2 models cannot be viewed in Model Viewer but they work fine in Hammer model preview.