Libraries of commonly used blocks can be created. Many building components are used repeatedly in different projects in any given office. A library of commonly used blocks can be created, and added to as new parts are used. This provides not only a fast way to create new drawings, by inserting details as pre-drawn blocks, but also constancy of drawing across different projects in an office. Blocks are extremely efficient at keeping the database small.
Blocks can contain non graphical information.
Blocks allow you to save non-graphical information that might not be displayed, but is still saved with the database. This information might be the part number of a type of window, the diameter and composition of a reinforcing bar, the cost and description of a desk etc. Having created the database, it is possible to extracted the non-graphical data into a spreadsheet or database, and produce a bill of materials directly from the drawing. As the drawing is changed, so the bill of materials is updated automatically. Creating a block is simply the process of supplying a name, identifying the entities to be included, and finally supplying the base point, or point by which it will be inserted.