UNDERLAY
ENTITIES Section
VIEWPORT
The following group codes apply to vertex
entities. 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.
|
Vertex
group codes
|
|
Group code
|
Description
|
|
100
|
Subclass
marker (AcDbVertex)
|
|
100
|
Subclass
marker (AcDb2dVertex or AcDb3dPolylineVertex)
|
|
10
|
Location
point (in OCS when 2D, and WCS when 3D)
DXF: X value;
APP: 3D point
|
|
20, 30
|
DXF: Y and Z values
of location point (in OCS when 2D, and WCS when 3D)
|
|
40
|
Starting
width (optional; default is 0)
|
|
41
|
Ending
width (optional; default is 0)
|
|
42
|
Bulge (optional;
default is 0). The bulge is the tangent of one fourth the included
angle for an arc segment, made negative if the arc goes clockwise
from the start point to the endpoint. A bulge of 0 indicates a straight
segment, and a bulge of 1 is a semicircle
|
|
70
|
Vertex
flags:
1 = Extra vertex created by curve-fitting
2 = Curve-fit
tangent defined for this vertex. A curve-fit tangent direction of
0 may be omitted from DXF output but is significant if this bit
is set
4 = Not used
8 = Spline
vertex created by spline-fitting
16 = Spline
frame control point
32 = 3D
polyline vertex
64 = 3D
polygon mesh
128 = Polyface mesh vertex
|
|
50
|
Curve fit
tangent direction
|
|
71
|
Polyface
mesh vertex index (optional; present only if nonzero)
|
|
72
|
Polyface
mesh vertex index (optional; present only if nonzero)
|
|
73
|
Polyface
mesh vertex index (optional; present only if nonzero)
|
|
74
|
Polyface
mesh vertex index (optional; present only if nonzero)
|
Every vertex that is part of a polyface mesh
has its vertex flag 128 bit set. If the entity supplies the coordinate
of a vertex of the mesh, its 64 bit is set as well, and the 10,
20, 30 groups give the vertex coordinate. The vertex index values
are determined by the order in which the vertex entities appear
within the polyline, with the first being numbered 1.
If the vertex defines a face of the mesh, its
vertex flags group has the 128 bit set but not the 64 bit. In this
case, the 10, 20, 30 (location) groups of the face entity are irrelevant
and are always written as 0 in a DXF file. The vertex indexes that
define the mesh are given by 71, 72, 73, and 74 group codes, the values
of which specify one of the previously defined vertexes by index.
If the index is negative, the edge that begins with that vertex
is invisible. The first 0 vertex marks the end of the vertices of
the face.