100

Subclass marker (AcDbViewport)

10

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

20, 30

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

40

Width in paper space units

41

Height in paper space units

68

Viewport status field:
-1 = On, but is fully off screen, or is one of the viewports that is not active because the $MAXACTVP count is currently being exceeded.
0 = Off
<positive value > = On and active. The value indicates the order of stacking for the viewports, where 1 is the active viewport, 2 is the next, and so forth.

69

Viewport ID.

12

View center point (in DCS)
DXF: X value; APP: 2D point

22

DXF: View center point Y value (in DCS)

13

Snap base point
DXF: X value; APP: 2D point

23

DXF: Snap base point Y value

14

Snap spacing
DXF: X value; APP: 2D point

24

DXF: Snap spacing Y value

15

Grid spacing
DXF: X value; APP: 2D point

25

DXF: Grid spacing Y value

16

View direction vector (in WCS)

DXF: X value; APP: 3D vector

26, 36

DXF: Y and Z values of view direction vector (in WCS)

17

View target point (in WCS)

DXF: X value; APP: 3D vector

27, 37

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

42

Perspective lens length

43

Front clip plane Z value

44

Back clip plane Z value

45

View height (in model space units)

50

Snap angle

51

View twist angle

72

Circle zoom percent

341

Frozen layer object ID/handle (multiple entries may exist) (optional)

90

Viewport status bit coded flags:
1 (0x1) = Enables perspective mode
2 (0x2) = Enables front clipping
4 (0x4) = Enables back clipping
8 (0x8) = Enables UCS follow
16 (0x10) = Enables front clip not at eye
32 (0x20) = Enables UCS icon visibility
64 (0x40) = Enables UCS icon at origin
128 (0x80) = Enables fast zoom
256 (0x100) = Enables snap mode
512 (0x200) = Enables grid mode
1024 (0x400) = Enables isometric snap style
2048 (0x800) = Enables hide plot mode
4096 (0x1000) = kIsoPairTop. If set and kIsoPairRight is not set, then isopair top is enabled. If both kIsoPairTop and kIsoPairRight are set, then isopair left is enabled.
8192 (0x2000) = kIsoPairRight. If set and kIsoPairTop is not set, then isopair right is enabled.
16384 (0x4000) = Enables viewport zoom locking
32768 (0x8000) = Currently always enabled
65536 (0x10000) = Enables non-rectangular clipping
131072 (0x20000) = Turns the viewport off

340

Hard-pointer ID/handle to entity that serves as the viewport's clipping boundary (only present if viewport is non-rectangular)

1

Plot style sheet name assigned to this viewport

281

Render mode:
0 = 2D Optimized (classic 2D)
1 = Wireframe
2 = Hidden line
3 = Flat shaded
4 = Gouraud shaded
5 = Flat shaded with wireframe
6 = Gouraud shaded with wireframe

All rendering modes other than 2D Optimized engage the new 3D graphics pipeline. These values directly correspond to the SHADEMODE command and the AcDbAbstractViewTableRecord::RenderMode enum

71

UCS per viewport flag:
0 = The UCS will not change when this viewport becomes active.
1 = This viewport stores its own UCS which will become the current UCS whenever the viewport is activated.

74

Display UCS icon at UCS origin flag:

Controls whether UCS icon represents viewport UCS or current UCS (these will be different if UCSVP is 1 and viewport is not active).  However, this field is currently being ignored and the icon always represents the viewport UCS.

110

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

120, 130

DXF: Y and Z values of UCS origin

111

UCS X-axis
DXF: X value; APP: 3D vector

121, 131

DXF: Y and Z values of UCS X-axis

112

UCS Y-axis
DXF: X value; APP: 3D vector

122, 132

DXF: Y and Z values of UCS Y-axis

345

ID/handle of AcDbUCSTableRecord if UCS is a named UCS.  If not present, then UCS is unnamed.

346

ID/handle of AcDbUCSTableRecord of base UCS if UCS is orthographic (79 code is non-zero).  If not present and 79 code is non-zero, then base UCS is taken to be WORLD.

79

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

146

Elevation