Blocks are collections of DXF entities which can be placed multiple times as block references in different layouts and other block definitions. The block reference (Insert) can be rotated, scaled, placed in 3D space by OCS and arranged in a grid like manner, each Insert entity can have individual attributes (Attrib) attached.

Block Attributes

A block attribute (Attrib) is a text annotation attached to a block reference with an associated tag. Attributes are often used to add information to block references which can be evaluated and exported by CAD applications.

Extended Block Features

Autodesk added many new features to BLOCKS (dynamic blocks, constraints) as undocumented DXF entities, many of these features are not fully supported by other CAD application and ezdxf also has no support or these features beyond the preservation of these undocumented DXF entities.