The vector's magnitude and direction is best understood when the dislocation-bearing crystal structure is first visualized without the dislocation, that is, the perfect crystal structure. In this perfect crystal structure, a rectangle whose lengths and widths are integer multiples of  (the unit cell edge length) is drawn encompassing the site of the original dislocation's origin. Once this encompassing rectangle is drawn, the dislocation can be introduced.
The vector's magnitude and direction are most comprehensible when the crystal structure, devoid of dislocations, is first visualized. In this perfect crystal structure, a rectangle whose lengths and widths are integer multiples of  (the unit cell edge length) is drawn around the original dislocation's origin site. Once this rectangle is drawn, the dislocation can be incorporated.