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
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
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.