Move the control points of the single line on the image to determine the X-axis of the model.
When moving the position of the single line, select and move the center control point. It only changes the position of the single line but not the length or angle.
When changing the length and angle of the single line, select and move either of the control points on the both ends.
Click [RESET] to return the single line edits back to the original status.
Click [UNDO] to cancel the previous operation.
Set the displayed single line on the workpiece and click [OK].
The direction of X-axis of the model is determined.