authors |
Wohlers, T. |
year |
1995 |
title |
3D Digitizers for Engineering |
source |
Computer Graphics World, (March 1995), p. 112-115 |
summary |
3D digitizing systems permit you to create a digital model from a physical part. The process is appealing because it can be difficult to create models of complex objects using computer tools without the aid of a 3D input device. Recreating an existing part from scratch, even with a computer, is like copying a printed page by retyping it. Although 3D digitizers are not as straightforward as a photocopy machine, the intent is the same. You can render and print a digitized model to communicate shape information, extract dimensions from it to show size information, and use the 3D database to manufacture a replica using rapid prototyping (RP) and CNC machines. You can also include the 3D model in multimedia or animation software as a learning or assembly aid. The challenge of the digitization process in manufacturing is to capture adequate detail and resolution. Adding a digitized model to a Hollywood film is often much easier than reverse engineering a part for prototyping or manufacturing. The only criteria for a movie or TV commercial is whether or not it looks good. No one from the audience measures the object to see if it meets a given tolerance. In manufacturing, RP and CNC machines require clean, complete, and accurate information. If areas on the model are incomplete or missing, it may be difficult or impossible to build the part. If edges, grooves, and features of the part are not fine and crisp, the results may be less than satisfactory. Most 3D digitizing systems are best at digitizing organic shapes such as free-form sculpted surfaces. When you see an advertisement or a catalog from companies offering digitized models, often you see objects such as human anatomy, animals, bones, skeletons, and so on. You may also see cars, trucks, motorcycles and airplanes, although they can be more difficult to digitize. Highly engineered parts, such as enclosures for electronic devices are usually the most difficult for 3D digitizers. That's why these systems aren't used widely for the reverse engineering of precision mechanical parts. |
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2003/04/23 15:50 |
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