Arc group codes
Group codes 	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
100 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