SKN/BMF
From Just Solve the File Format Problem
SKN/BMF is a 3D mesh format used in the Sims series, found in both ASCII text (SKN) and binary (BMF) formats. It is a deformable mesh referencing a 2D image used as the texture. The text (SKN) format can express greater precision in its numeric values than the binary format, but otherwise the two formats are renditions of identical data structures.