When one or more points have been selected you can force them all to fit into a grid. Imagine a 3D grid of stacked cubes. The size of the cubes is given by the Grid Size in the Post Processing Options Dialog. The grid lines up with current Cartesian coordinate system as defined by the current scale status (as shown at top of Point Table). When a point is fit to the grid it is moved to the closest corner of one of these stacked cubes.