DXF file, HEADER, and group codes for direction

[Dan Shedd]

I am a DXF newbie, tryign to create DXF fiels from a Fortran program. I have used the Basic programming examples in the DXF_r13.HLP file to create a series of write statements to create line entities, ala ;

0
SECTION
2
ENTITIES
0
LINE
08
WING
10
0.283000E+02
20
0.000000E+00
30
-.140000E+01
11
0.285975E+02
21
0.000000E+00
31
-.106204E+01
0

this works great. I can use AECVIZ reader to view these files in 3D. However, sometimes I need to view these files in a graphics conversion program, and for obvious reasons I can only see 2D. Problem is I want to change the orientation or view before I load it into a 2D paint program. ie rotate the entire drawing by 90 degrees. I found a section in the help file that indicates there is a variable called $ANGBASE in the HEADER section with a group code of 50, that appears to let me do this. However, I cannot seem to make this work. AECVIZ crashes when I use a HEADER

0
SECTION
2
HEADER
50
1.57
0
ENTITIES
0
LINE
08
WING
10
0.283000E+02
20
0.000000E+00
30
-.140000E+01
11
0.285975E+02
21
0.000000E+00
31
-.106204E+01
0

do I need to add a group code of 50 and angle value (in radians?) to each LINE entity, or just in a header?

would appreciate any help in identifying my problems.

tia

dan