Drawing Parallel Lines


Another common CAD function is to draw parallel lines. You frequently want parallel lines when drawing the walls of a floor plan or when drawing a cross section of a flat metal assembly, for example. In AutoCAD, you can do this in two ways. You can use the Multiline command, which draws parallel lines and arcs, and you can use the Offset command to copy objects to a set distance. The overall effect of the Offset command is to draw a line parallel to an existing one.

The Offset command makes parallel copies of objects and is the most flexible way to draw parallel lines. It works with lines, arcs, circles, splines, and polylines, so you can produce just about any parallel line you might need (see Figure 3.12). Since it works with splines and polylines, you can easily draw complex parallel curves.

image from book
Figure 3.12: Examples of parallel lines created using Offset

No matter what type of object you're trying to make parallel copies of, the operation is the same. Here are the steps to use the Offset command:

  1. image from book Click the Offset tool in the second row of tools in the 2D Draw control panel, choose Modify è Offset, or enter O at the command prompt.

  2. At the Specify offset distance or [Through/Erase/Layer] <Through>: prompt, indicate a distance by either entering a distance through the keyboard or selecting two points in the drawing area. You can use osnaps to indicate distances based on existing objects in the drawing.

  3. At the Select object to offset or [Exit/Undo] <Exit>: prompt, select the object you want to copy.

  4. At the Specify point on side to offset or [Exit,Multiple/Undo] <Exit>: prompt, select the side of the object where you want the copy to appear. AutoCAD creates a parallel copy at the distance you specified in step 2.

  5. Repeat steps 3 and 4 for more parallel copies, or press to exit the Offset command.

You might notice the Through option in step 2. If you enter T at the prompt in step 2 to invoke the Through option, AutoCAD prompts you with Specify through point: at step 4. You can then select a point through which the parallel copy is to pass. This option is useful when you know where the parallel line is to pass but you do not know the distance.




Introducing AutoCAD 2008
Introducing AutoCAD 2008
ISBN: 0470121505
EAN: 2147483647
Year: 2007
Pages: 147
Authors: George Omura

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