Entities in the database normally belong to an AcDbBlockTableRecord. The block table in a newly created database has three predefined records, *MODEL_SPACE, *PAPER_SPACE, and *PAPER_SPACE0, which represent model space and the two pre-defined paper space layouts. Additional records are added whenever the user creates new blocks (block records), typically by issuing a BLOCK, HATCH, or DIMENSION command.
The ownership structure for database entities is as follows:
