All DXF objects can only reside in the OBJECTS section of a DXF document.
The purpose of the OBJECTS section is to allow CAD software developers to define and store custom objects that are not included in the basic DXF file format. These custom objects can be used to represent complex data structures, such as database tables or project management information, that are not easily represented by basic DXF entities.
By including custom objects in the OBJECTS section, CAD software developers can extend the functionality of their software to support new types of data and objects. For example, a custom application might define a new type of block or dimension style that is specific to a particular industry or workflow. By storing this custom object definition in the OBJECTS section, the CAD software can recognize and use the new object type in a drawing.
In summary, the OBJECTS section is an important part of the DXF file format because it allows CAD software developers to extend the functionality of their software by defining and storing custom objects and entity types. This makes it possible to represent complex data structures and workflows in CAD drawings, and allows CAD software to be customized to meet the specific needs of different industries and applications.