# AX

The AX function computes the relative rotational displacement of marker I with respect to marker J about the X-axis of marker J.

AX(I, J)

## Description

The computed angle takes into account the total number of revolutions between the two markers. While computing this angle, it is assumed that rotations about the other two axes of marker J (Y and Z) are zero. The AX angle is the angle between the two Y-axes measured counterclockwise from the Y-axis of marker J.

## Arguments

I
The marker whose rotational displacement is to be computed. Must be specified.
J
The marker with respect to which the rotational displacement is to be computed. This argument is optional. If omitted, it defaults to the ground coordinate system.

## Example

<Force_Vector_TwoBody
id                   = "104004"
type                 = "TorqueOnly"
i_marker_id          = "10415720"
j_floating_marker_id = "10416721"
ref_marker_id        = "10416720"
tx_expression        = "-(1000)*(AX(10415720,10416720))+(0)-(10)*WX(10415720,10416720,10416720)"
ty_expression        = "-(1000)*(AY(10415720,10416720))+(0)-(10)*WY10415720,10416720,10416720)"
tz_expression        = "-(100)*(AZ(10415720,10416720))+(0)-(1)  *WZ(10415720,10416720,10416720)"
/>
OR
<Post_Request
comment              = "Left Caster/Kingpin Inclination"
id                   = "71000030"
type                 = "EXPRESSION"
expr1                = "NULL"
expr2                = "(AY(10803060,30101010))*RTOD"
expr3                = "-(AX(10803060))*RTOD"
expr4                = "NULL"
expr5                = "NULL"
expr6                = "NULL"
expr7                = "NULL"
expr8                = "NULL"
/>