Laser projection for positioning tasks

Single laser lines can be used if the alignment only has to work for one degree of freedom. This may be a single edge of an object, the hem of textiles, the edge of a sheet of paper, plastics or metal etc., as long as it forms a straight line.   

If alignment is only needed in one axis, parallel lines may help to give a visual limit stop and/or define a permitted area for placement. If the width of objects changes, a system with movable laser lines can be used.

Rectangular objects may be positioned by projecting a cross or two perpendicular lines. However, the single lines must be long enough in relation to the object to guarantee proper alignment.
Two crosses, displayed by a crosshair laser at opposing corners of a rectangular shape, may define the exact position, e.g. of a label.

Laser points can be used to align objects that lack straight or perpendicular outlines. Three points may mark a circular outline. If an object has an irregular outline or distinctive features like grooves, gaps, recesses or mechanical marks, two or more laser points may define the position. Certain tasks may be solved by using combinations of points, lines or crosses.