3DS
From Just Solve the File Format Problem
3DS is the original (legacy) file format for Kinetix' 3D Studio and 3D Studio MAX product line (now part of AutoDesk). It contains the 3D model data for the complete scene.
See also the successor format, MAX.
Identification
3DS files begin with bytes 0x4D 0x4D
. (Note that many TIFF files begin the same way, though 3DS is not related to TIFF.)