# [Possible Bug?] Use Relative or Absolute Station in Axis variable (GAXV)?

I have two models below:

1. The axis is a 10m strsight line, the height of cross section (TVAR variable H) is 500mm at S=0m and S=10m, while it’s 1500mm at S=5m.
+PROG AQUA urs:1
CTRL FACE NEG
UNIT 5 DIG 3
ECHO SECT EXTR
NORM GB 50010-2010
CONC NO TYPE FCN
1 C 40
SECT NO MNO
1 1
TVAR H 1000[mm]
TVAR B 1000[mm]
POLY TYPE
O
VERT NO Y Z
1 ‘=#B/2’ ‘=#H/2’
2 ‘=#B/2’ ‘=-#H/2’
3 ‘=-#B/2’ ‘=-#H/2’
4 ‘=-#B/2’ ‘=#H/2’
END
+PROG SOFIMSHC urs:2
PAGE UNII 0
SYST 3D GDIR NEGZ GDIV -1000
CTRL TOLG 0.01
CTRL MESH 1
CTRL HMIN -
CTRL TOPO GAXP 0
CTRL NODE 1000
GAX AI0 TYPE LANE
GAXB X1 0 0 0 S1 0 X2 10 0 0 S2 1
LET#S_ACT 0
GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 0.5 V 1500
GAXV AI0 NAME H S 1 V 500
GAXP AI0 S 0 TITL ‘P1’ TYPE ‘A’
GAXP AI0 S 1 TYPE ‘E’
SLN 1003 GRP - SNO 1 DRX 0 0 -1 STYP B REF ‘AI0’ NPA 1001 NPE 1002
SPT 1001 X 0 0 0
SPT 1002 X 10 0 0
END
+PROG AQUA
INTE 0
END

As for straight line axis, I have to use RELATIVE station (S) in GAXV, to get the correct result.

GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 0.5 V 1500
GAXV AI0 NAME H S 1 V 500

S=0.5 means S=5m, S=1 means S=10m.

If I use ABSOLUTE station (S) in GAXV,

GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 5 V 1500
GAXV AI0 NAME H S 10 V 500

I got incorrect result

1. The axis is an arc with 5m radius, the height of cross section (TVAR variable H) is 500mm at S=0m and S=5 * Pi/2 (at end), while it’s 1500mm at S=5 * Pi/4 (at middle).
Aqua is the same as case 1
+PROG SOFIMSHC urs:2
PAGE UNII 0
SYST 3D GDIR NEGZ GDIV -1000
CTRL TOLG 0.01
CTRL MESH 1
CTRL HMIN -
CTRL TOPO GAXP 0
CTRL NODE 1000
GAX AI0 TYPE LANE
GAXB X1 5 0 0 S1 0 X2 -5 0 0 S2 15.70796327 XM 0 0 0 NX 0 0 1
LET#S_ACT 0
GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 3.926990817 V 1500
GAXV AI0 NAME H S 7.853981634 V 500
GAXP AI0 S 0 TITL ‘P1’ TYPE ‘A’
GAXP AI0 S 7.853981634 TITL ‘P2’ TYPE ‘E’
SLN 1003 GRP - SNO 1 DRX 0 0 -1 STYP B REF ‘AI0’ NPA 1001 NPE 1002
SPT 1001 X 5 0 0
SPT 1002 X 0 5 0
END
+PROG AQUA
INTE 0
END

As for curve axis, I have to use ABSOLUTE station (S) in GAXV, to get the correct result.

GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 3.926990817 V 1500
GAXV AI0 NAME H S 7.853981634 V 500

3.926990817=5 * Pi/4
7.853981634=5 * Pi/2

If I use RELATIVE station (S) in GAXV,

GAXV AI0 NAME H S 0 V 500
GAXV AI0 NAME H S 0.5 V 1500
GAXV AI0 NAME H S 1 V 500

I got incorrect result

You forgot the hashtag:
‘=#H/2’

1 Like

Thanks. I add more contents in my post.