| TVA Relies on Advanced Software to Keep Pace with CAD Demands
By Kevin Corbley At a time when organizations are increasingly turning to outside contractors as an inexpensive source of data conversion services, the CAD Solutions group within Tennessee Valley Authority (TVA) is thriving. In fact, the department's operations have become so efficient, the group pays for itself.
The 60-member group provides drafting, scanning, and conversion support to the TVA corporation spread across 7 southeastern US states. It credits its financial self-sufficiency to innovative uses of personnel and applications of the latest software technology.
"We make sure that our staff has the best tools available," says Garnett Johnson, CAD Solutions' program administrator. "We cross train our people to have skills in different software products."
Nearly everyone in the shop is proficient in AutoCAD, Image Tracer, and Image Edit-the three primary software packages utilized to complete most major projects sent to CAD Solutions from various TVA engineering and design teams.
In 1994, the department established a "School-to-Work" program involving students at a local Knoxville, Tennessee, high school. Since then, the program has blossomed to include seven schools whose students learn computer aided drafting in class, assist in actual projects at TVA, and become eligible for hiring by CAD Solutions.
TVA provided computers to the participating schools, and CAD Solutions' employees have spent thousands of hours lending experience to teachers and students alike. Hitachi Software Global Technology Ltd. (HSGT) of Westminster, Colorado, donated 12 copies of its Image Tracer and Image Edit software for the students to use in their training.
In a typical project, a TVA engineer draws new designs or changes to existing facility plans directly on a hardcopy mylar, linen, or vellum print. These are sent to CAD Solutions where they are scanned and the files are imported into AutoCAD. A CAD technician then uses the computerized program to produce a digital file of the proposed design or make changes to an existing file.
After drawings are scanned but before they are manipulated in AutoCAD, CAD technicians first clean up the raster drawing file using HSGT's Image Edit tool which runs inside AutoCAD. This editing software enables the technician to remove speckle from the digital drawing that may remain from creases or blemishes on the hardcopy. In addition, pixels and symbols can be erased or added to the design so that it conforms with other digital files.
"A wide variety of rubber sheeting commands in Image Edit are often applied at this stage to rectify the drawing so it is positioned and scaled correctly," says HSGT's Chris Hall. Once the digital raster drawing is cleaned up, the technician converts it to a vector file with the Image Tracer software, accelerating the conversion process. With parameters set by the operator to accommodate particular drawing types, including contour maps, parcel maps, or architectural drawings, the software automatically follows lines on the raster file and converts them to AutoCAD polylines, circles, and arcs.
"We convert files to vector format because they are much smaller and easier to manipulate than raster files," says Johnson. "This reduces manual work by 20 to 25 percent during conversion."
When the program is tracing a line in the raster file such as a topographic contour, it automatically stops when it meets a line gap or intersection point. Image Tracer then finds all possible continuation routes and allows the operator to select the appropriate direction.
The resulting vector files are extremely accurate conversions of the originals due to a precise raster snapping feature and unlimited N-point rubber sheeting capability in the software. The vector trace is saved as a standard AutoCAD DWG file and stored in TVA's drawing vault. Giving Students a Head Start
Regardless of whether CAD Solutions is working on one single large project, as is now the case with the transmission network conversion, or a series of smaller drafting tasks, the entire staff and its 60 Windows computers are constantly in use.
The School-to-Work program has enabled the group to maintain its high level of quality, consistency, and efficiency on a number of fronts. Foremost, community service has long been a primary goal of the organization.
The program now involves four Knoxville schools and three others outside the city. In class, the students learn to use the same AutoCAD, Image Edit, and Image Tracer packages as are employed at CAD Solutions. Those students who show an interest are invited to work up to 4 hours a day at the CAD Solutions shop inside TVA. They assist in actual projects, earning both money and experience.
By the time the students finish the classroom work, they know the software inside and out. After that, they simply need to learn project specification standards utilized by CAD Solutions, and they are fully employable as CAD technicians.
"If students understand computer basics, which most do today, they can pick up AutoCAD or Image Tracer very easily," says Bales. "It only takes a couple weeks to learn Image Tracer, for example."
"The program benefits the industry as a whole," says HSGT's Hall. "Many students who do not ultimately work at CAD Solutions go on to study CAD, GIS, and related disciplines in college, thanks to their introduction to the technology in the TVA School-to-Work program." About the Author
Kevin Corbley is a freelance writer specializing in the GeoTechnologies. He is located in Denver and may be reached at [email protected] Back |
