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
129=1+128
置顶卡
