Expert Training

Plotting

If you plan to use color-dependent plot styles (most people do), develop a color-to-lineweight plotting chart like Table 14-1. If you choose the more logical but lonelier named plot styles approach, make a similar chart, with plot style names instead of color in the first column. (See Chapter 12 for information about color-dependent and named plot styles.) After you complete a plotting chart, create a plot style table (CBT file for color-dependent plot styles or STB file for named plot styles), as in Chapter 12.

Warning Your life will be easier — and your plotting chart will be shorter — if you limit yourself to a small portion of the 255 colors in the AutoCAD Color Index (ACI). The first nine colors work well for many people.

Tip If your work requires screened (shaded or faded-out) lines, extend the plotting chart to include a couple of additional AutoCAD colors. For each color, list the plotted lineweight and screen percentage ranging from 0% for invisible to 100% for solid black.

Layers

After you work out your plotting conventions, you’re ready to develop a chart of layers. A chart of layers takes more thought and work, and you’ll probably revise it more frequently than the plotting chart. Find a typical drawing from your office or industry and identify the things you’ll draw — such as walls, text, dimensions, and hatching. Then decide how you’d like to parse those objects onto different layers (see Chapter 4). Here are some rules:

• Objects that you want to plot with different lineweights go on different layers. Assign each layer a different color, lineweight, or named plot style; let the objects inherit these properties from the layer.

• Objects whose visibility you want to control separately go on different layers. Turn off or freeze a layer in order to make the objects on that layer, and only the objects on that layer, disappear temporarily.

• Objects that represent significantly different kinds of things in the real world go on different layers. For example, doors should go on different layers from walls in an architectural floor plan.

As you make your layer decisions, you’ll develop a layer chart that resembles Table 14-2. If you use named plot styles instead of color-dependent plot styles, add a Plot style column to the chart.

Warning The layer chart in Table 14-2 is simpler than the layer systems used by experienced drafters in most companies. The layer names in the table are based on names in the AIA CAD Layer Guidelines document mentioned in the “Industry standards” sidebar. That document recommends adding a discipline-specific prefix to each layer name: A-Walls for walls drawn by the architectural team, S-Walls for walls drawn by the structural team, and so on.

Technical Stuff For a discussion of CAD layer standards in architecture, engineering, and construction, see the article “AEC Layer Debate — AIA Sets the Standard” http://www.cadalyst.com/features/0601layer/0601layer.htm. If you enjoy reading articles like this one, you may be CAD manager material!

Other stuff

The following settings and procedures deserve some consistency, too:

• Text styles. Decide on text fonts and heights and use them consistently. (See Chapter 9 for more information.)

  Tip Manual CAD drafting standards often specify a minimum text height of 1⁄8 inch or 3 mm, because hand-lettered text smaller than that becomes difficult to read, especially on half-size prints. Plotted 3⁄32 inch or 2.5 mm CAD text is quite legible, but half-size plots with these smaller text heights can result in text that’s on the margin of legibility. Text legibility on half-size — or smaller — plots depends on the plotter resolution, the lineweight assigned to the text, and the condition of your eyes. Test before you commit to using smaller text heights, or use 1⁄8 inch or 3 mm as a minimum.

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Dimension styles. Create a dimension style that reflects your preferred look and feel. (See Chapter 10.) Hatch patterns. Choose the hatch patterns that you need and decide on an appropriate scale and angle for each. (See Chapter 11.) Drawing setup and organization. Set up all of the drawings on a project in the same way, and use blocks and xrefs in a consistent fashion.

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After you make standards, make sure that the plotted results are fine. You’ll undoubtedly revise and extend your standards as you go, especially on your first few projects. In time, you’ll find a set of standards that work for you.