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Trends in Reverse Engineering
1 May, 2008 By: Jeffrey RoweAffordability and greater ease of use result in more respect for the reverse-engineering market.
Over the years, reverse engineering (RE) has suffered from a lack of respect. While the "engineering" part of the term has always been regarded positively, the term as a whole has suffered because of the negative connotations associated with the word "reverse." In many people's minds, RE involves the illegal act of copying (in effect, stealing) an original design, whether the design is for software or a physical product. The old perception, however, is changing. As a result, RE's image is changing, too.
Simply put, RE is the process by which you digitally reconstruct a physical part. This is significant, because it's estimated that as many as 80% of new designs come from existing ones (usually from existing parts and assemblies). RE is part of a larger scheme increasingly known as digital shape sampling and processing (DSSP). DSSP involves several technologies that, put together, bridge the physical and digital worlds.
Unlike the time when RE was considered the process of illegally copying a product, legitimate RE applications now include the following:
- 1. creating data for refurbishing or manufacturing parts that have no associated CAD data
- 2. creating 3D data from a model or sculpture for game and movie animations
- 3. creating, scaling, or reproducing artwork
- 4. measuring, documenting, and recreating cultural objects or museum artifacts
- 5. generating data for creating dental or surgical prosthetics or for surgical planning
- 6. inspecting and conducting quality control by comparing a fabricated part to its CAD description.
Many potential users wrongly assume that RE technology is beyond their means. Today, such technology is available as an affordable desktop solution for small-and medium-sized businesses. Depending on the scanning technology used, you will find an entry-level price point of less than $15,000 that includes all the hardware and software needed for getting started in RE.
DSSP data for manufacturing purposes involves two distinct methods of describing and representing 3D forms. RE does this by handling geometry as sets of discrete points (whereas traditional CAD does it with shapes defined by continuous curves and surfaces). Combined, RE and CAD transform physical objects into digital objects (and ultimately back to physical objects). In other words, RE extracts geometric information from physical objects, and CAD reconstructs objects into a digital form that can be used for creating physical objects based on the scanned data.
The Basics
RE is a process of examination. The part under consideration is not modified during the scanning/digitizing stage (that would make it re-engineering), although it can be modified in downstream applications, such as CAD.
The data-related portion of the RE process has two parts: scanning and data manipulation. Scanning, also called digitizing, is the process of gathering geometric point data from an object. Several different contact and noncontact technologies are used to collect this 3D data. Each technology has advantages and disadvantages, and their applications and specifications overlap.
What eventually results from each of the data-collection methods is a description of the physical object in 3D space called a point cloud. Point-cloud data typically defines points on the surface of a scanned object in terms of x, y, z coordinates. At each x, y, z coordinate in the data where there is a point, there is an associated surface coordinate of the original object.
There usually is too much data in the point cloud collected from a scanner/digitizer, and some of it will be unwanted noise. Without further processing, the data cannot be used by downstream applications, such as CAD/CAM software or in rapid prototyping. RE software is used to edit point-cloud data, establish the connections of the cloud points, and translate it into useful formats, including surface and solid models or STL files. It also combines several different scans of an object so that the data describing the object can be defined completely from all sides.
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