UCS (DXF)

 
 
 

The following group codes apply to UCS symbol table entries.

UCS group codes

Group code

Description

100

Subclass marker (AcDbUCSTableRecord)

2

UCS name

70

Standard flag values (bit-coded values):

16 = If set, table entry is externally dependent on an xref

32 = If both this bit and bit 16 are set, the externally dependent xref has been successfully resolved

64 = If set, the table entry was referenced by at least one entity in the drawing the last time the drawing was edited. (This flag is for the benefit of AutoCAD commands. It can be ignored by most programs that read DXF files and need not be set by programs that write DXF files)

10

Origin (in WCS)

DXF: X value; APP: 3D point

20, 30

DXF: Y and Z values of origin (in WCS)

11

X-axis direction (in WCS)

DXF: X value; APP: 3D vector

21, 31

DXF: Y and Z values of X-axis direction (in WCS)

12

Y-axis direction (in WCS)

DXF: X value; APP: 3D vector

22, 32

DXF: Y and Z values of Y-axis direction (in WCS)

79

Always 0

146

Elevation

346

ID/handle of base UCS if this is an orthographic. This code is not present if the 79 code is 0. If this code is not present and 79 code is non-zero, then base UCS is assumed to be WORLD

71

Orthographic type (optional; always appears in pairs with the 13, 23, 33 codes):

1 = Top; 2 = Bottom

3 = Front; 4 = Back

5 = Left; 6 = Right

13

Origin for this orthographic type relative to this UCS

DXF: X value of origin point; APP: 3D point

23, 33

DXF: Y and Z values of origin point

Each 71/13,23,33 pair defines the UCS origin for a particular orthographic type relative to this UCS. For example, if the following pair is present, then invoking the UCS/LEFT command when UCSBASE is set to this UCS will cause the new UCS origin to become (1,2,3).

71: 5
13: 1.0
23: 2.0
33: 3.0

If this pair were not present, then invoking the UCS/LEFT command would cause the new UCS origin to be set to this UCS's origin point.