It is the format pertaining to the Google SketchUp - The most easy-to-use 3D modeling tool. With Google SketchUp, you may:
Build 3D architectures, accessories and props.
Fast Photo texturing and Perspective Correction.
Create 3D Terrain.
Create 3D Text.
Import PNG Billboard Objects such as grass, fence or sign board easily made by Photoshop or any PNG tools with transparency info.
Please see Appendix C for more details.
The 3ds file format is made up of chunks. They describe what information is to follow and what it is made up, it's ID and the location of the next block. If you don't understand a chunk you can quite simply skip it. The next chunk pointer is relative to the start of the current chunk and in bytes. The binary information in the 3ds file is written in a special kind of way. Namely the lest significant byte comes first.
Most of the time, the exported 3DS will comes compacted with their texture files such as JPEG, BMP, PNG, TIFF or TGA (targa).
Please see Appendix A for more details.
Object files define the geometry and other properties for objects. They can be in ASCII format (.obj) or binary format (.mod). The .obj file format supports both polygonal objects and free-form objects. Polygonal geometry uses points, lines, and faces to define objects while free-form geometry uses curves and surfaces.
the exported OBJ will come with the MTL (Material) file, which contains texture and material settings.
Please see Appendix B for more details.