All meshes must be made of triangles.
All texture filenames are limited to the 8.3 DOS format.
The number of vertices and polygons per mesh is limited to 65536.
Accurate vertex normals cannot be stored in the .3ds file. Instead "smoothing groups"[5] are used so that the receiving program can recreate a (hopefully good) representation of the vertex normals. This is still a hold-over legacy for many animation programs today which started in the 1980's (3DS MAX, Lightwave and trueSpace still use smoothing groups, and Maya up to v2.51).
Object, light and camera names are limited to 10 characters. Material names are limited to 16 characters.
Directional light sources are not supported.