Graphics Programs Reference
In-Depth Information
Chapter 13
Copying Existing Drawings
into AutoCAD
At times, you'll want to turn an existing drawing into an AutoCAD drawing file. The original
drawing may be hand drawn, or it might be a PDF from another source. You may be modi-
fying a design that someone else created or converting your library of older, hand-drafted
drawings for AutoCAD use. Perhaps you want to convert a hand-drawn sketch into a formal
drawing? This chapter discusses ways to import existing drawings into AutoCAD through
tracing, scaling, and scanning.
In this chapter, you'll learn to do the following:
Convert paper drawings into AutoCAD iles
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Import a raster image
Work with a raster image
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Methods for Converting Paper Drawings to AutoCAD Files
Scaling a drawing is the most flexible method for converting paper drawings into AutoCAD files
because you don't need a graphics tablet to do it, and generally, you're faced with fewer cleanups
afterward. Scaling also facilitates the most accurate input of orthogonal lines because you can
read dimensions directly from the drawing and enter them into AutoCAD. The main drawback
with scaling is that if the hand-drafted drawing does not contain written dimensions, it would
be difficult to produce an accurate copy. In addition, you must constantly look at the hand-
drafted drawing and measure distances with a scale, and irregular curves are difficult to scale
accurately. Programs are available that automatically convert an image file into an AutoCAD
drawing file consisting of lines and arcs. These programs may offer some help, but they require
some editing and checking for errors.
Tra c ing with a digitizing tablet used to be the only way to enter a hand-drafted drawing into
AutoCAD. However, a traced drawing usually requires some cleanup and reorganization.
Scanning , much like tracing, is best used for drawings that are difficult to scale, such as com-
plex topographical maps containing more contours than are practical to trace on a digitizer or
nontechnical line art such as letterhead and logos.
The simplest method for converting paper drawings, and the method covered in this chapter,
is to scan your drawings as image files to be used as a background in AutoCAD. You can import
your image files into AutoCAD and then trace directly over them. This technique allows you to
see the original drawing in the AutoCAD window, preventing you from diverting your atten-
tion to other areas of your workstation.
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