The following group codes apply to arc entities.
Arc group codes
Group code
Description
100
Subclass marker (AcDbCircle)
39
Thickness (optional; default = 0)
10
Center point (in OCS)
DXF: X value; APP: 3D point
20, 30
DXF: Y and Z values of center point (in OCS)
40
Radius
Subclass marker (AcDbArc)
50
Start angle
51
End angle
210
Extrusion direction (optional; default = 0, 0, 1)
DXF: X value; APP: 3D vector
220, 230
DXF: Y and Z values of extrusion direction (optional)