Creating DXF Spline programmatically

I need to create spline programmatically. I've made something like:

0
SECTION
  2
HEADER
  9
$ACADVER
  1
AC1006
  0
ENDSEC
  0
SECTION
  2
TABLES
  0
TABLE
2
LAYER
  0
LAYER
 2
shape
 70
 64
 62
 250
 6
CONTINUOUS
 0
LAYER
 2
holes
 70
 64
 62
 250
 6
CONTINUOUS
 0
ENDTAB
 0
ENDSEC
0
SECTION
2
ENTITIES
0
SPLINE
8
shape
100
AcDbSpline
210
0
220
0
230
1
70
4
71
3
72
11
73
4
74
4
42
0.0000001
43
0.0000001
44
0.0000000001
40
0
40
0
40
0
40
0
40
1
40
1
40
1
40
2
40
2
40
2
40
2
10
0
20
0
30
0
10
100
20
50
30
0
10
40
20
40
30
0
10
15
20
23
30
0
11
0
21
0
31
0
11
200
21
200
31
0
11
80
21
80
31
0
11
432
21
234
31
0
0
ENDSEC
0
EOF

When I'm trying to open it in Autodesk TrueView, I'm getting an error:

Undefined group code 210 for object on line 54. Invalid or incomplete DXF input -- drawing discarded.

Where is the error? When I'm copying just SPLINE section to the DXF generated by AI everything works fine. So I think I need to add something in the header section or something.

Solution

This file is DXF version AC1006 which is older than DXF R12. The SPLINE entity requires at least DXF version AC1012 DXF R13/R14. But with DXF version AC1012 the tag structure of DXF files is changed (OBJECTS and CLASSES sections, SubClassMarkers ...), so just editing the DXF version does not work.

Also the SPLINE entity seems to be invalid, it has no handle (5) and no owner tag (330), and the whole AcDbEntity subclass is missing.