Do you mean resetting the relative grid or parts already placed ?
To reset the relative grid press 'o' (orientation) while nothing is selected and the mouse cursor is inside the editing view.
To align a selection to the current grid press home, or shift+home to align on all 3 axis.
To reset the rotation of a selection press ctrl+home.
To reset the relative grid press 'o' (orientation) while nothing is selected and the mouse cursor is inside the editing view.
To align a selection to the current grid press home, or shift+home to align on all 3 axis.
To reset the rotation of a selection press ctrl+home.