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 this bit and bit 16 are both 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

Orthographic view type:
0 = UCS is not orthographic;
1 = Top; 2 = Bottom;
3 = Front; 4 = Back;
5 = Left; 6 = Right

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