Reverse engineering (RE), the process by which an existing item is identically reproduced, becomes necessary when a physical prototype exists, but an accurate geometric data file of the part does not.

In order to recreate the existing part, a computerized (CAD) model of the part must be drawn or otherwise acquired. This CAD file provides the coordinates of multiple points on the product surface, which is then used to develop the drawing of the product for redesign or manufacturing. This data may then be analyzed within the CAD program or exported to a machine capable of rebuilding the new design or its tool, such as rapid prototyping (RP) or rapid tooling (RT) equipment. Although the automatic regeneration of the CAD model without the time-consuming use of CAD software is merely a single step in the RE process, it has become the focus of the RE community due to the ongoing pursuit to acquire more accurate 3-D data in a faster and less expensive manner.

Collecting accurate geometric data of any manufactured part is complicated by the numerous surface curvatures and odd shapes associated with manufactured products. Inaccurate data can be obtained using handheld devices such as calipers, but the time required to gather sufficient quantities of this data becomes extensive and the results become susceptible to inevitable human error. Until the advancement of automated RE technologies, acquiring substantial amounts of data with acceptable precision was nearly impossible.

The rapid advancement of computer technology has given rise to numerous automated RE methods that utilize a broad range of technologies to acquire data. These technologies provide extremely precise 3-D geometric information of nearly any item. Two of these technologies, contact scanning and laser scanning, have become increasingly popular in several manufacturing industries due to their speed, accuracy and relatively low cost.