Chapter 6 -- ENTITIES Section
DIMENSION
Common Dimension Group Codes

The following group codes apply to all dimension entity types. In addition to the group codes described here, see "Common Group Codes for Entities." For information about abbreviations and formatting used in this table, see "Formatting Conventions in This Reference."

Common dimension group codes
Group codes Description

100

Subclass marker (AcDbDimension)

2

Name of the block that contains the entities that make up the dimension picture

10

Definition point (in WCS)
DXF: X value; APP: 3D point

20, 30

DXF: Y and Z values of definition point (in WCS)

11

Middle point of dimension text (in OCS)
DXF: X value; APP: 3D point

21, 31

DXF: Y and Z values of middle point of dimension text (in OCS)

70

Dimension type.
Values 0-6 are integer values that represent the dimension type. Values 32, 64, and 128 are bit values, which are added to the integer values (value 32 is always set in R13 and later releases).
0 = Rotated, horizontal, or vertical; 1 = Aligned;
2 = Angular; 3 = Diameter; 4 = Radius;
5 = Angular 3 point; 6 = Ordinate;
32 = Indicates that the block reference (group code 2) is referenced by this dimension only.
64 = Ordinate type. This is a bit value (bit 7) used only with integer value 6. If set, ordinate is X-type; if not set, ordinate is Y-type.
128 = This is a bit value (bit 8) added to the other group 70 values if the dimension text has been positioned at a user-defined location rather than at the default location.

71

Attachment point:
1 = Top left; 2 = Top center; 3 = Top right;
4 = Middle left; 5 = Middle center; 6 = Middle right;
7 = Bottom left; 8 = Bottom center; 9 = Bottom right

72

Dimension text line spacing style (optional):
1(or missing) = At least (taller characters will override)
2 = Exact (taller characters will not override)

41

Dimension text line spacing factor (optional):
Percentage of default (3-on-5) line spacing to be applied. Valid values range from 0.25 to 4.00.

42

Actual measurement (optional; read-only value)

1

Dimension text explicitly entered by the user. Optional; default is the measurement. If null or "<>", the dimension measurement is drawn as the text, if " " (one blank space), the text is suppressed. Anything else is drawn as the text.

53

The optional group code 53 is the rotation angle of the dimension text away from its default orientation (the direction of the dimension line)  (optional).

51

All dimension types have an optional 51 group code, which indicates the horizontal direction for the dimension entity. The dimension entity determines the orientation of dimension text and lines for horizontal, vertical, and rotated linear dimensions.
This group value is the negative of the angle between the OCS X axis and the UCS X axis. It is always in the XY plane of the OCS.

210

Extrusion direction (optional; default = 0, 0, 1)
DXF: X value; APP: 3D vector

220, 230

DXF: Y and Z values of extrusion direction  (optional)

3

Dimension style name

Xdata belonging to the application ID "ACAD" follows a dimension entity if any dimension overrides that have been applied to this entity. See "Dimension Style Overrides."

For all dimension types, the following group codes represent 3D WCS points:

For all dimension types, the following group codes represent 3D OCS points: