How to Indicate Lineweight in AutoCAD

By Bill Fane

Long ago, manual drafters developed the practice of drawing lines of different widths (lineweights) to distinguish different kinds of objects. Manual drafters did it with different technical ink pen nib diameters or with different hardnesses of pencil lead and varying degrees of pressure on the pencil. Because a computer mouse usually doesn’t come supplied with mouse balls of different diameters, AutoCAD developers had to figure out how to let users indicate lineweights onscreen and on plots. They came up with two different ways to indicate lineweight:

  • Mapping onscreen colors to plotted lineweights.
  • Displaying lineweights onscreen to match what the user can expect to see on the plot: This approach appeared in AutoCAD 2000.

Controlling plotted lineweights with object lineweights

Plotting object lineweights is trivial, assuming that the person who created the drawing first assigned a lineweight property to layers or objects. Just make sure that the Plot Object Lineweights check box in the expanded Plot dialog box is selected. You can also deselect the Plot with Plot Styles check box because plot styles can override the object lineweights with different plotted lineweights.

You can also make these settings in the Page Setup dialog box for the appropriate Layout or Model tab. To access the Page Setup Manager, right-click the Quick View Layouts button on the status bar and choose Page Setup Manager.

If you want object lineweights to control plotted lineweights, make sure that the Plot Object Lineweights check box is selected in the Plot Options area of the Plot or Page Setup dialog box. If you don’t want to plot the lineweights assigned to objects, you must deselect both the Plot Object Lineweights and Plot with Plot Styles check boxes in the Plot or Page Setup dialog box. Selecting Plot with Plot Styles selects Plot Object Lineweights as well.

Controlling plotted lineweights with screen colors

To map screen colors to plotted lineweights, you need a color-dependent plot style table (CTB file). If you’re plotting a drawing created by someone else, that person may be able to supply you with the appropriate CTB file, or at least with a PCP or PC2 file from which you can create the CTB file quickly. The creator of the drawing should be able to supply at least a printed chart showing which plotted lineweight to assign to each AutoCAD screen color.

Unfortunately, no industry-wide standards exist for mapping screen colors to plotted lineweights. Different offices do it differently. That’s why it’s useful to receive a CTB, PCP, or PC2 file with drawings that clients send you. If they use eTransmit, the plot style tables and plotter configuration files are included in the package.

After you have the appropriate CTB file stored in the Plot Styles folder, follow these steps to use it:

  1. Move the mouse pointer across the Layout tabs at the bottom of the screen. A preview of each layout appears as you hover the cursor on each tab.
  2. Right-click the tab of the layout that you want to plot. A multi-item context menu appears with a number of items related to layouts.
  3. Click the Plot item in the context menu. The Plot dialog box appears with the name of the layout to be plotted displayed on the title bar.
  4. In the Plot Style Table (Pen Assignments) area of the Plot dialog box, select the CTB file from the drop-down list. The plot style table (CTB file) is attached to the layout or model space tab that you clicked in Step 2. If the drawing uses a named plot style table instead of a color-dependent plot style table, select an STB file instead of a CTB file.
  5. Click the Apply to Layout button. AutoCAD records the plot setting change with the current layout’s configuration information. Assuming that you save the drawing, AutoCAD uses the CTB you selected as the default plot style when you (or other people) plot this layout in the future.
  6. Continue with your plotting procedure.
plotted lineweights
Selecting a plot style table that maps screen colors to plotted lineweights.

You can tell whether the current drawing was set up to use color-dependent plot styles or named plot styles by looking at the Properties panel on the Ribbon’s Home tab. If the upper-right drop-down list is grayed out, shows ByColor, and doesn’t display a tooltip, the drawing uses color-dependent plot styles. If this list isn’t grayed out and displays the Plot Style tooltip, the drawing uses named plot styles.