# HEADER Section¶

The HEADER section of the DXF file contains settings of variables associated with the drawing. The following list shows the header variables and their meanings.

set/get header variables:

```
#set value
drawing.header['$ANGBASE'] = 30
drawing.header['$EXTMIN'] = (0, 0, 0)
drawing.header['$EXTMAX'] = (100, 100, 0)
#get value
version = drawing.header['$ACADVER'].value
# for 2D/3D points use:
minx, miny, minz = drawing.header['$EXTMIN'].tuple
maxx, maxy, maxz = drawing.header['$EXTMAX'].tuple
```

Variable | Type | Description |
---|---|---|

$ACADVER | string | The AutoCAD drawing database version number; AC1006 = R10, AC1009 = R11 and R12 |

$ANGBASE | float | Angle 0 direction |

$ANGDIR | int | 1 = clockwise angles, 0 = counterclockwise |

$ATTDIA | int | Attribute entry dialogs, 1 = on, 0 = off |

$ATTMODE | int | Attribute visibility: 0 = none, 1 = normal, 2 = all |

$ATTREQ | int | Attribute prompting during INSERT, 1 = on, 0 = off |

$AUNITS | int | Units format for angles |

$AUPREC | int | Units precision for angles |

$AXISMODE | int | Axis on if nonzero (not functional in Release 12) |

$AXISUNIT | 2DPoint | Axis X and Y tick spacing (not functional in Release 12) |

$BLIPMODE | int | Blip mode on if nonzero |

$CECOLOR | int | Entity color number; 0 = BYBLOCK, 256 = BYLAYER |

$CELTYPE | string | Entity linetype name, or BYBLOCK or BYLAYER |

$CHAMFERA | float | First chamfer distance |

$CHAMFERB | float | Second chamfer distance |

$CLAYER | string | Current layer name |

$COORDS | int | 0 = static coordinate display, 1 = continuous update, 2 = “d<a” format |

$DIMALT | int | Alternate unit dimensioning performed if nonzero |

$DIMALTD | int | Alternate unit decimal places |

$DIMALTF | float | Alternate unit scale factor |

$DIMAPOST | string | Alternate dimensioning suffix |

$DIMASO | int | 1 = create associative dimensioning, 0 = draw individual entities |

$DIMASZ | float | Dimensioning arrow size |

$DIMBLK | string | Arrow block name |

$DIMBLK1 | string | First arrow block name |

$DIMBLK2 | string | Second arrow block name |

$DIMCEN | float | Size of center mark/lines |

$DIMCLRD | int | Dimension line color, range is 0 = BYBLOCK, 256 = BYLAYER |

$DIMCLRE | int | Dimension extension line color, range is 0 = BYBLOCK, 256 = BYLAYER |

$DIMCLRT | int | Dimension text color, range is 0 = BYBLOCK, 256 = BYLAYER |

$DIMDLE | float | Dimension line extension |

$DIMDLI | float | Dimension line increment |

$DIMEXE | float | Extension line extension |

$DIMEXO | float | Extension line offset |

$DIMGAP | float | Dimension line gap |

$DIMLFAC | float | Linear measurements scale factor |

$DIMLIM | int | Dimension limits generated if nonzero |

$DIMPOST | string | General dimensioning suffix |

$DIMRND | float | Rounding value for dimension distances |

$DIMSAH | int | Use separate arrow blocks if nonzero |

$DIMSCALE | float | Overall dimensioning scale factor |

$DIMSE1 | int | First extension line suppressed if nonzero |

$DIMSE2 | int | Second extension line suppressed if nonzero |

$DIMSHO | int | 1 = Recompute dimensions while dragging, 0 = drag original image |

$DIMSOXD | int | Suppress outside-extensions dimension lines if nonzero |

$DIMSTYLE | string | Dimension style name |

$DIMTAD | int | Text above dimension line if nonzero |

$DIMTFAC | float | Dimension tolerance display scale factor |

$DIMTIH | int | Text inside horizontal if nonzero |

$DIMTIX | int | Force text inside extensions if nonzero |

$DIMTM | float | Minus tolerance |

$DIMTOFL | int | If text outside extensions, force line extensions between extensions if nonzero |

$DIMTOH | int | Text outside horizontal if nonzero |

$DIMTOL | int | Dimension tolerances generated if nonzero |

$DIMTP | float | Plus tolerance |

$DIMTSZ | float | Dimensioning tick size: 0 = no ticks |

$DIMTVP | float | Text vertical position |

$DIMTXT | float | Dimensioning text height |

$DIMZIN | int | Zero suppression for “feet & inch” dimensions |

$DWGCODEPAGE | int | Drawing code page. Set to the system code page when a new drawing is created, but not otherwise maintained by AutoCAD |

$DRAGMODE | int | 0 = off, 1 = on, 2 = auto |

$ELEVATION | float | Current elevation set by ELEV command |

$EXTMAX | 3DPoint | X, Y, and Z drawing extents upper-right corner (in WCS) |

$EXTMIN | 3DPoint | X, Y, and Z drawing extents lower-left corner (in WCS) |

$FILLETRAD | float | Fillet radius |

$FILLMODE | int | Fill mode on if nonzero |

$HANDLING | int | Handles enabled if nonzero |

$HANDSEED | string | Next available handle |

$INSBASE | 3DPoint | Insertion base set by BASE command (in WCS) |

$LIMCHECK | int | Nonzero if limits checking is on |

$LIMMAX | 2DPoint | XY drawing limits upper-right corner (in WCS) |

$LIMMIN | 2DPoint | XY drawing limits lower-left corner (in WCS) |

$LTSCALE | float | Global linetype scale |

$LUNITS | int | Units format for coordinates and distances |

$LUPREC | int | Units precision for coordinates and distances |

$MAXACTVP | int | Sets maximum number of viewports to be regenerated |

$MENU | string | Name of menu file |

$MIRRTEXT | int | Mirror text if nonzero |

$ORTHOMODE | int | Ortho mode on if nonzero |

$OSMODE | int | Running object snap modes |

$PDMODE | int | Point display mode |

$PDSIZE | float | Point display size |

$PELEVATION | float | Current paper space elevation |

$PEXTMAX | 3DPoint | Maximum X, Y, and Z extents for paper space |

$PEXTMIN | 3DPoint | Minimum X, Y, and Z extents for paper space |

$PLIMCHECK | int | Limits checking in paper space when nonzero |

$PLIMMAX | 2DPoint | Maximum X and Y limits in paper space |

$PLIMMIN | 2DPoint | Minimum X and Y limits in paper space |

$PLINEGEN | int | Governs the generation of linetype patterns around the vertices of a 2D Polyline 1 = linetype is generated in a continuous pattern around vertices of the Polyline 0 = each segment of the Polyline starts and ends with a dash |

$PLINEWID | float | Default Polyline width |

$PSLTSCALE | int | Controls paper space linetype scaling 1 = no special linetype scaling 0 = viewport scaling governs linetype scaling |

$PUCSNAME | string | Current paper space UCS name |

$PUCSORG | 3DPoint | Current paper space UCS origin |

$PUCSXDIR | 3DPoint | Current paper space UCS X axis |

$PUCSYDIR | 3DPoint | Current paper space UCS Y axis |

$QTEXTMODE | int | Quick text mode on if nonzero |

$REGENMODE | int | REGENAUTO mode on if nonzero |

$SHADEDGE | int | 0 = faces shaded, edges not highlighted 1 = faces shaded, edges highlighted in black 2 = faces not filled, edges in entity color 3 = faces in entity color, edges in black |

$SHADEDIF | int | Percent ambient/diffuse light, range 1-100, default 70 |

$SKETCHINC | float | Sketch record increment 0 = sketch lines, 1 = sketch polylines |

$SKPOLY | int | |

$SPLFRAME | int | Spline control polygon display, 1 = on, 0 = off |

$SPLINESEGS | int | Number of line segments per spline patch |

$SPLINETYPE | int | Spline curve type for PEDIT Spline (See your AutoCAD Reference Manual) |

$SURFTAB1 | int | Number of mesh tabulations in first direction |

$SURFTAB2 | int | Number of mesh tabulations in second direction |

$SURFTYPE | int | Surface type for PEDIT Smooth (See your AutoCAD Reference Manual) |

$SURFU | int | Surface density (for PEDIT Smooth) in M direction |

$SURFV | int | Surface density (for PEDIT Smooth) in N direction |

$TDCREATE | float | Date/time of drawing creation |

$TDINDWG | float | Cumulative editing time for this drawing |

$TDUPDATE | float | Date/time of last drawing update |

$TDUSRTIMER | float | User elapsed timer |

$TEXTSIZE | float | Default text height |

$TEXTSTYLE | string | Current text style name |

$THICKNESS | float | Current thickness set by ELEV command |

$TILEMODE | int | 1 for previous release compatibility mode, 0 otherwise |

$TRACEWID | float | Default Trace width |

$UCSNAME | string | Name of current UCS |

$UCSORG | 3DPoint | Origin of current UCS (in WCS) |

$UCSXDIR | 3DPoint | Direction of current UCS’s X axis (in World coordinates) |

$UCSYDIR | 3DPoint | Direction of current UCS’s Y axis (in World coordinates) |

$UNITMODE | int | Low bit set = display fractions, feet-and-inches, and surveyor’s angles in input format |

$USERI1 - 5 | int | Five integer variables intended for use by third-party developers |

$USERR1 - 5 | float | Five real variables intended for use by third-party developers |

$USRTIMER | int | 0 = timer off, 1 = timer on |

$VISRETAIN | int | 0 = don’t retain Xref-dependent visibility settings, 1 = retain Xref-dependent visibility settings |

$WORLDVIEW | int | 1 = set UCS to WCS during DVIEW/VPOINT, 0 = don’t change UCS |