DXF Group Codes
BLOCKS Section
BLOCK

The following group codes apply to block entities.

Block group codes
Group codes Description

0

Entity type (BLOCK)

5

Handle

102

Start of application defined group "{application_name". For example, "{ACAD_REACTORS" indicates the start of the AutoCAD persistent reactors group

application-defined codes


Codes and values within the 102 groups are application-defined.

102

End of group, "}"

100

Subclass marker (AcDbEntity)

8

Layer name

100

Subclass marker (AcDbBlockBegin)

2

Block name

70

Block-type flags (bit coded values, may be combined):
1 = This is an anonymous block generated by hatching, associative dimensioning, other internal operations, or an application
2 = This block has attribute definitions
4 = This block is an external reference (xref)
8 = This block is an xref overlay
16 = This block is externally dependent
32 = This is a resolved external reference, or dependent of an external reference (ignored on input)
64 = This definition is a referenced external reference (ignored on input)

10

Base point. DXF: X value; APP: 3D point

20, 30

DXF: Y and Z values of base point

3

Block name

1

Xref path name (optional; present only if the block is an xref)

The UCS in effect when a block definition is created becomes the WCS for all entities in the block definition. The new origin for these entities is shifted to match the base point defined for the block definition. All entity data is translated to fit this new WCS.

*MODEL_SPACE and *PAPER_SPACE Block Definition

Now, there are always two extra, empty definitions in the BLOCKS section, titled *MODEL_SPACE and *PAPER_SPACE. These definitions manifest the new representation of model space and paper space as block definitions internally. The entities contained in these definitions still appear in the ENTITIES section for compatibility.

Model Space and Paper Space Entity Segregation

The interleaving between model space and paper space will no longer occurs, because of internal organization. Instead, all paper space entities are output, followed by model space entities. The flag distinguishing them is the group code 67.