Sign Convention

XYZ Convention

The following convention is used for the XYZ axes of EX3 models:

• X-axis and Y-axis make up the horizontal plane
• Z-axis is always the vertical axis and is positive upwards.
• Rotation follows the right-hand rule where the thumb is pointing in the positive direction along the axis of rotation and the curled fingers indicate the positive rotation direction. This applies for all inputted angles in the program except for Trend and Plunge. See below for more information.

Trend and Plunge

The trend is the rotation angle about the vertical Z axis measured from the Y axis (north). Positive is taken as rotating from the Y axis (north) towards the X axis (east). Plunge is the rotation angle downwards from the horizontal XY plane after the Trend angle is applied.

Stress Conventions

Refer to the Stress Conventions document in the Theory section.