CIRCLE codes 210-230

[DavidGraham]

I'm creating a DXF file containing 3D circles - see below.

In  the fist case the circle is just 2D, in the second case with the addition of codes 210, 220 & 230 (extrusion direction) the circle is 3D. Both circles are centred on the same point but the codes 10, 20 & 30 (centre point) are different.

How do I work out what codes 10, 20, 30, 210, 220, 230 should be when I know the centre coordinates and the extrusion direction.   

  0
CIRCLE
  8
L_BFC
 10
-6.9288
 20
-5.6034
 30
3.2438
 40
0.1331
  0
CIRCLE
  8
0
 10
7.4879
 20
5.3712
 30
-2.2386
 40
0.1327
210
-0.0891
220
0.8292
230
0.5519

In the second example I changed just the 210, 220 & 230 values - I expected the circle to stay in the same location and just the orientation - but the circle moves to a new location (with .

  0
SECTION
  2
ENTITIES
  0
LINE
  8
L_VCL
 10
-6.9288
 20
-5.6034
 30
3.2438
 11
-6.6511
 21
-4.7621
 31
3.7076
  0
CIRCLE
  8
L_BFC
 10
-6.9288
 20
-5.6034
 30
3.2438
 40
0.1331
  0
CIRCLE
  8
0
 10
7.4879
 20
5.3712
 30
-2.2386
 40
0.1327
210
0.2777
220
0.8413
230
0.4638
  0
ENDSEC
  0
EOF

 How do I work out what codes 10, 20, 30, 210, 220, 230 should be, when I know the centre coordinates and the extrusion direction? 

[Roy_043]

(setq PointInOCS (trans PointInWCS 0 normal))