Chapter 5

Keeping Track of Layers and Blocks

Imagine a filing system that has only one category into which you put all your records. For only a handful of documents, such a filing system might work. However, as soon as you start to accumulate more documents, you would want to start separating them into meaningful categories, perhaps alphabetically or by their use, so you could find them more easily.

The same is true for drawings. If you have a simple drawing with only a few objects, you can get by without using layers. But as soon as your drawing gets the least bit complicated, you’ll want to start sorting your objects into layers to keep track of what’s what. Layers don’t restrict you when you’re editing objects such as blocks or groups, and you can set up layers so that you can easily identify which object belongs to which layer.

In this chapter, you’ll learn how to create and use layers to keep your drawings organized. You’ll learn how color can play an important role while you’re working with layers, and you’ll also learn how to include linetypes such as dashes and center lines through the use of layers.

In this chapter, you’ll learn to do the following:

• Organize information with layers
• Control layer visibility
• Keep track of blocks and layers

Organizing Information with Layers

You can think of layers as overlays on which you keep various types of information (see Figure 5-1). In a floor plan of a building, for example, you want to keep the walls, ceiling, plumbing fixtures, wiring, and furniture separate so that you can display or plot them individually or combine them in different ways. It’s also a good idea to keep notes and reference symbols, as well as the drawing’s dimensions, on their own layers. As your drawing becomes more complex, you can turn the various layers on and off to allow easier display and modification.

For example, one of your consultants might need a plot of just the dimensions and walls, without all the other information; another consultant might need only a furniture layout. Using manual drafting, you would have to redraw your plan for each consultant or use overlay drafting techniques, which can be cumbersome. With AutoCAD, you can turn off the layers you don’t need and plot a drawing containing only the required information. A carefully planned layering scheme helps you produce a document that combines the types of information needed in each case.

Using layers also lets you modify your drawings more easily. For example, suppose you have an architectural drawing with separate layers for the walls, the ceiling plan, and the floor plan. If any change occurs in the wall locations, you can turn on the ceiling plan layer to see where the new wall locations will affect the ceiling and then make the proper adjustments.

AutoCAD allows an unlimited number of layers, and you can name each layer anything you want using any characters with the exception of these: < > / “ ” : ; ? * | , = ‘ ’.

Creating and Assigning Layers

You’ll start your exploration of layers by using the Layers palette and the Properties Inspector palette to create a new layer, giving it a name, and assigning it a color. Then, you’ll look at alternate ways of creating a layer through the command line. Next, you’ll assign the new layer to the objects in your drawing. Start by getting familiar with the Layers palette:

You could have selected a color from the Color pop-up list, but by using the Select Color option, you were introduced to the Color Palette dialog box.

From this point on, any object assigned to the Wall layer will appear green unless the object is specifically assigned a different color.

I’d like to point out another method for setting layer colors. In addition to using the Properties Inspector palette, you can set the layer color using the Color column in the Layers palette. The Color column is the one with the square icon (Figure 5-5).

When a layer is assigned a color other than white, the color is displayed in this column. You can click this column to open a pop-up menu that offers the same color options you saw in the Properties Inspector palette.

Using the Properties Inspector Palette to Set Layer Options

Now let’s take a closer look at how the Properties Inspector palette interacts with the Layers palette. In Chapter 4, you saw how the Properties Inspector palette displays information about objects in your drawing. When you click on a layer in the Layers palette, the Properties Inspector palette displays the properties of the selected layer. Try the following to see firsthand how this works:

The Properties Inspector palette offers several pop-up lists that enable you to change the layer properties such as color, linetype, and line weight. Layer transparency can be controlled with a slider. You used the Color pop-up list to select a color for the Wall layer in the previous exercise.

You’ll also want to know about the two icons in the upper-left corner of the Properties Inspector palette. They are labeled Current and Layer (Figure 5-7). These icons enable you to switch between displaying the properties of an object in the drawing and the current layer.

You’ll get a chance to use some of the other settings later in this chapter. Let’s continue with a closer look at some other layer features.

Using True or PANTONE Colors

In an earlier exercise, you chose a color from the Index Color tab of the Color Palette dialog box. Most of the time, you’ll find that the Index Color tab includes enough colors to suit your needs. But if you’re creating a presentation drawing in which color selection is important, you can choose colors from either the True Color tab or the Color Books tab of the Color Palette dialog box.

The True Color tab offers a full range of colors through a color palette similar to the one found in Adobe Photoshop and other image editing programs (Figure 5-8).

You have the choice of using hue, saturation, and luminance, which is the HSL color mode, or you can use the RGB (red, green, blue) color mode. You can select HSL or RGB from the Mode drop-down list in the upper-right corner of the dialog box (Figure 5-9).

You can also select from PANTONE, RAL, and DIC color books by using the Color Books tab (Figure 5-10). Color books are “books” that contain color samples with their corresponding number code. If you’ve ever gone to a paint store to select a color, chances are you’ve used one. In AutoCAD, the color books are displayed as a list of colors and codes.

Let’s continue with our look at layers in AutoCAD.

Understanding the Layers Palette

The most prominent feature of the Layers palette is the layer list box, as you saw in the preceding exercise. As you add them, the list box begins to fill up with layers. Notice that the bar at the top of the list of layers offers several buttons for the various layer properties. You can adjust the width of the Name column in the list of layers by clicking and dragging either side of the column head. You can also sort the layer list based on the name at the top of the list. And just as with other Mac list boxes, you can also click names to select a block of layer names, or you can F-click individual names to select multiple layers that don’t appear together. These features will become helpful as your list of layers grows.

You’ve already seen how the New Layer icon works. To delete layers, you select a layer or group of layers and then click the Delete Layer icon, which looks like a minus sign. Be aware that you can’t delete layer 0, locked layers, or layers that contain objects. You can also see at a glance which layer is the current drawing layer by the gray highlighted row in the layer list. Right now, layer 0 is highlighted in gray (Figure 5-11). This is the layer on which objects will be placed when you’re drawing in the drawing area.

Note that just clicking on a layer does not make it the current drawing layer. When you click on a layer to set its properties, it is highlighted in blue. If you click on the Wall layer, it will be highlighted in blue while layer 0 will continue to be highlighted in gray.

Another way to create or delete layers is to select a layer or set of layers from the list box and then right-click. A menu appears, offering additional options that you can apply to selected layers (Figure 5-12). Table 5-1 describes the function of these options.

Table 5-1: The Layers palette shortcut menu options

Option Name	Function
Set Current	Sets the selected layer to be the current drawing layer
New Layer	Creates a new layer
Rename Layer	Renames the selected layer
Delete Layer	Deletes the selected layer(s) with the option to delete its contents when objects are present on the layer
New Layer VP Frozen In All Viewports	Creates a new layer that is frozen in all viewports
VP Freeze Layer In All Viewports	Freezes selected layer(s) in all viewports
VP Thaw Layer In All Viewports	Thaws selected layers in all viewports
Isolate Selected Layers	Hides (turns off) all but the selected layer(s) in the drawing
Select All	Selects all the layers that are displayed in the layer list
Clear All	Clears the selection of layers in the layer list
Select All But Current	Selects all but the current layer
Invert Selection	Inverts the selection of layers in the list

You’ll also notice another set of icons at the top of the Layers palette. Those icons offer features to control and manage layers. You’ll get a closer look at them a little later in this chapter in the section “Using Objects to Control Layers.”

Controlling Layers through the Layer Command

You’ve seen how the Layers palette makes it easy to view and edit layer information and how you can easily select layer colors from the Color Palette dialog box. But you can also control layers through the Command prompt.

Use these steps to control layers through the Command prompt:

Each method of controlling layers has its own advantages. The Layers palette offers more information about your layers at a glance. On the other hand, the Layer command offers a quick way to control and create layers if you’re in a hurry. Also, if you intend to write custom macros and scripts, you’ll want to know how to use the Layer command as opposed to using the Layers palette because palettes can’t be controlled through custom macros or scripts.

Assigning Layers to Objects

When you create an object, that object is assigned to the current layer. Until now, only one layer has existed—layer 0—and it contains all the objects you’ve drawn so far. Now that you’ve created some new layers, you can reassign objects to them by using the Properties Inspector palette:

The bathroom walls are now on the new layer called Wall, and the walls are changed to green. Layers are more easily distinguished from one another when you use colors to set them apart.

Next, you’ll practice the commands you learned in this section and try some new ones by creating new layers and changing the layer assignments of the rest of the objects in your bathroom:

For blocks, you can change the color assignment and linetype of only those objects that are on layer 0 within a block. See the sidebar “Controlling Colors and Linetypes of Blocked Objects” later in this chapter.

Continue by creating new layers and assigning objects to them:

Layer Name	Color
Ceiling	Magenta (6)
Jamb	Green (3)
Floor	Cyan (4)

In step 2 of the previous exercise, you used the Properties Inspector palette, which offered several options for modifying the block. The options displayed in the Properties Inspector palette depend on the objects you’ve selected. With only one object selected, AutoCAD displays options that apply specifically to that object. With several objects selected, you’ll see a more limited set of options because AutoCAD can change only those properties that are common to all the objects selected.

Working on Layers

So far, you’ve created layers and then assigned objects to them. In this section, you’ll continue to use the Layer pop-up list in the Properties Inspector palette to assign layers to objects. In the process, you’ll make some additions to the drawing.

The current layer is still layer 0, and, unless you change the current layer, every new object you draw will be on layer 0. Here’s how to change the current layer:

Because you assigned the color green to the Jamb layer, the two lines you just drew to represent the door jambs are green. This gives you immediate feedback about which layer you’re on as you draw.

Now you’ll use the part of the wall between the jambs as a line representing the door header (the part of the wall above the door). To do this, you’ll have to cut the line into three line segments and then change the layer assignment of the segment between the jambs:

Although it may not be obvious, you’ve just broken the right-side wall line into three line segments: one at the door opening and two more on either side of the jambs. You can also use the Break tool (to the left of the Break At Point tool) to produce a gap in a line segment.

The Break At Point icon won’t work on a circle. You can, however, use the Break tool, also on the Modify panel, to place a small gap in the circle. If you create a small enough gap, the circle will still look like a full circle.

Next you’ll change the Layer property of the line between the two jambs to the Ceiling layer. But instead of using the Properties Inspector palette as you’ve done in earlier exercises, you’ll use a shortcut method:

In this exercise, you saw that when you select an object with no command active, the object’s properties are immediately displayed in the Properties Inspector palette under Color, Linetype, and Lineweight. Using this method, you can also change an object’s color, linetype, and line weight independent of its layer. Just as with the Properties Inspector palette, you can select multiple objects and change their layers through the Layer pop-up list.

Now, you’ll finish the bathroom by adding a sink to a layer named Casework:

Controlling Layer Visibility

I mentioned earlier that you’ll sometimes want to display only certain layers to work with in a drawing. In this bathroom is a door header that would normally appear only in a reflected ceiling plan. To turn off a layer so that it becomes invisible, you click the On/Off icon in the Layers palette, as shown in these steps:

With the Ceiling layer off, the line representing the door header disappears.

There are a few other icons and corresponding columns that appear with each of the layers in the layer list but they may be hidden from view. Use the scroll bar at the bottom of the Layer palette to scroll the list to the left. You’ll see three more icons. These are Freeze/Thaw, Lock/Unlock, Plot/No Plot (Figure 5-16).

The Freeze/Thaw column controls the visibility of layers in a way similar to the On/Off icon. The Lock/Unlock column locks a layer to prevent accidental edits to objects on the layer. The Plot/No Plot column enables you to control whether a layer appears in printed output or if it only appears in the drawing on the computer screen. All of these columns at the top of the layer list are duplicated in the Properties Inspector palette and the properties they control can be set in both places.

Adding Control Features to the Layer List

As mentioned earlier, the Properties Inspector palette duplicates some of the settings found in the layer list of the Layers palette. You can include more of the layer properties in the layer list by using the Layers palette’s Display Settings icon. Click the Display Settings icon to view the pop-up menu (Figure 5-17). You’ll see a list of options, some of which have a check mark next to them. The options with the check mark are the ones that already appear in the layer list.

You can select an unchecked option to include it in the layer list. For example, if you select Status, a triangle marker appears in the layer list indicating the current layer.

The VP Freeze, VP Color, and VP Lineweight options are used when multiple viewports (VPs) are present. You’ll learn more about viewports in Chapter 8, “Introducing Printing and Layouts,” Chapter 15, “Laying Out Your Printer Output,” and Chapter 20, “Using Advanced 3D Features.” Viewports interact with layers in a unique way. A viewport is like a custom view of your drawing. You can have multiple viewports in a layout, each showing a different part of your drawing. Layer properties can be controlled for each viewport independently, so you can set up different linetypes, colors, and layer visibility for each viewport.

Toward the bottom of the list, you see three options that control the overall appearance of the list. Optimize All Columns compresses the columns to their smallest size, enabling you to see as many columns as possible within the layer list. Optimize Column adjusts the width of the columns so they fit comfortably within the width of the Layers palette. Restore All Columns To Defaults sets the columns to their default widths.

Finding the Layers You Want

With only a handful of layers, it’s fairly easy to find the layer you want to turn off. It becomes much more difficult, however, when the number of layers exceeds 20 or 30. The Layers palette offers some useful tools to help you find the layers you want quickly.

Suppose you have several layers whose names begin with C, such as C-lights, C-header, and C-pattern, and you want to find those layers quickly. You can click the Name button at the top of the layer list to sort the layer names in alphabetic order. (You can click the Name button again to reverse the order.) To select those layers for processing, click the first layer name that starts with C, and then scroll down the list until you find the last layer of the group and -click it. All the layers between those layers are selected. If you want to deselect some of those layers, hold down the F key while clicking the names of the layers you don’t want to include in your selection. Another option is to F-click the names of other layers you want selected.

The Color and On/Off column icons at the top of the list let you sort the list by virtue of the color or linetype assignments of the layers. Other column icons sort the list by virtue of status: Freeze/Thaw, Lock/Unlock, and so forth. (See the sidebar “Freeze, Lock, Transparency, and Other Layer Options” later in this chapter.)

Now try changing the layer settings again by turning off all the layers except Wall and Ceiling, leaving just a simple rectangle. In this exercise, you’ll get a chance to experiment with the On/Off options of the Layers palette:

In this exercise, you turned off a set of layers by clicking the On/Off column icon. You can freeze/thaw, lock/unlock, or change the color of a group of layers in a similar manner by clicking the appropriate layer column icon. For example, clicking a color column icon of one of the selected layers opens the Color Palette dialog box, in which you can set the color for all the selected layers.

Naming Layers to Stay Organized

If you name layers carefully, you can use them as a powerful layer-management tool. For example, suppose you have a drawing whose layer names are set up to help you easily identify floor-plan data versus ceiling-plan data, as in the following list:

• A-FP-WALL-JAMB
• A-FP-WIND-JAMB
• A-CP-WIND-HEAD
• A-CP-DOOR-HEAD
• L-FP-CURB
• C-FP-ELEV

The first character in the layer name designates the discipline related to that layer: A for architectural, L for landscape, C for civil, and so on. In this example, layers with names containing the two characters FP signify floor-plan layers. CP designates ceiling-plan information.

These layer name examples are loosely based on a layer naming convention devised by the American Institute of Architects (AIA). As you can see from this example, careful naming of layers can help you manage them.

Filtering Layers by Their Names

Once you start to use a layer-naming system, you can use the Layers palette’s Search text box to isolate layers that you want to work on. For example, if you want to isolate only those layers that have to do with floor plans, regardless of their discipline, enter -FP in the Layers palette’s Search text box. Once you do this, the layer list changes to display only layers with FP in their names. In addition, if you press ↵ after typing -FP, -FP becomes an option in the Search text box pop-up list, which can be opened by clicking the magnifying glass icon to the left of the list. (Figure 5-18).

Once you’ve filtered your layer list using the Search text box, you can turn off all of the remaining layers in the list, change their color assignment, or change other settings quickly without having to wade through a long list of layers you don’t want to touch. You can add more Search options to the Search text box list. AutoCAD keeps these options for future use until you delete them by selecting Clear from the Search text box pop-up menu.

As the number of layers in a drawing grows, you’ll find the Search text box an indispensable tool. But bear in mind that the successful use of the Search text box can depend on a careful layer-naming convention. If you’re producing architectural plans, you may want to consider the AIA layer-naming guidelines.

Assigning Linetypes to Layers

You’ll often want to use different linetypes to show hidden lines, center lines, fence lines, or other noncontinuous lines. You can assign a color and a linetype to a layer. You then see International Organization for Standardization (ISO) and complex linetypes, including lines that can be used to illustrate gas and water lines in civil work or batt insulation in a wall cavity.

AutoCAD comes with several linetypes, as shown in Figure 5-19. ISO linetypes are designed to be used with specific plotted line widths and linetype scales. For example, if you’re using a pen width of 0.5 mm, set the linetype scale of the drawing to 0.5 as well. (See Chapter 15 for more information on plotting and linetype scale.) You can also create your own linetypes (see Bonus Chapter 2 on the book’s companion website).

Linetypes that contain text, such as the gas-line sample at the bottom of Figure 5-19, use the current text height and font to determine the size and appearance of the text displayed in the line. A text height of zero displays the text properly in most cases. See Chapter 9, “Adding Text to Drawings,” for more on text styles.

AutoCAD stores linetype descriptions in an external file named Acad.lin, or Acadiso.lin for metric users. You can edit this file in a text editor like Notepad to create new linetypes or to modify existing ones. You’ll see how this is done in Bonus Chapter 2 on the book’s companion website.

Adding a Linetype to a Drawing

To see how linetypes work, you’ll add a DASHDOT line in the bathroom plan to indicate a shower curtain rod:

Controlling Linetype Scale

Although you’ve designated this as a DASHDOT line, it appears solid. Zoom in to a small part of the line and you’ll see that the line is indeed as you specified.

Because your current drawing is at a scale of 1˝ = 1´, you must adjust the scale of your linetypes accordingly. This is accomplished in the Linetype Manager dialog. Here are the steps:

You can also use the Ltscale system variable to set the linetype scale. Type LTS↵, and at the Enter new linetype scale factor <1.0000>: prompt, enter 12↵.

Remember that if you assign a linetype to a layer, everything you draw on that layer will be of that linetype. This includes arcs, polylines, circles, and traces. As explained in the sidebar “Assigning Colors, Linetypes, and Linetype Scales to Individual Objects” later in this chapter, you can also assign different colors and linetypes to individual objects rather than relying on their layer assignment to define color and linetype. However, you may want to avoid assigning colors and linetypes directly to objects until you have some experience with AutoCAD and a good grasp of your drawing’s organization.

In the previous exercise, you changed the global linetype scale setting. This affects all noncontinuous linetypes within the current drawing. You can also set the default linetype scale for all new objects with the Celtscale system variable (type CELTSCALE↵ and enter the desired scale factor).

When individual objects are assigned a linetype scale, they’re still affected by the global linetype scale set by the Ltscale system variable. For example, say you assign a linetype scale of 2 to the curtain rod in the previous example. This scale is then multiplied by the global linetype scale of 12, for a final linetype scale of 24.

You can also set the default linetype scale for individual objects by using the Celtscale system variable. After it’s set, only newly created objects are affected. You must use the Properties Inspector palette to change the linetype scale of individual existing objects.

Adding the Final Detail

If you’re working through the tutorial, your final task is to set up an insertion point for the current drawing to facilitate its insertion into other drawings in the future. Follow these steps:

Controlling Line Weights

You may have noticed a Lineweight option in the Properties Inspector palette. If you click this option for a given layer or object, a pop-up list that enables you to control the plotted thickness of your lines appears. Plotted line weights can be assigned directly to an object or to layers. You can view line weights as they will appear in your final plot by making setting changes in the Lineweights Settings dialog box, which you’ll learn about in Chapter 15.

With the Lineweight option and Lineweight Settings dialog box, you have greater control over the look of your drawings. This can save time because you don’t have to print your drawing just to check for line weights. You’ll be able to see how thick or thin your lines are as you edit your drawing.

Using Objects to Control Layers

You’ve seen the various tools used to control the layers in a drawing. AutoCAD also offers a set of icons that can help streamline many of the layer operations. You may have already noticed the row of icons at the top of the Layers palette. These icons enable you to set layer properties through the objects in your drawing.

For example, suppose you want to turn off the layer of a particular object in the drawing. You can select the object and then check the Properties Inspector palette to find its layer. Once you know the layer name, you can turn it off. But the Turn Off Object’s Layer icon in the Layers palette turns off an object’s layer with a single click, saving a few steps.

Figure 5-24 shows you the tooltip name of each icon and Table 5-2 describes how each tool is used. Keep these icons in mind as you work with AutoCAD. You’ll find they can be real timesavers.

Table 5-2: The Layers palette icons

Icon Name	Use
Make Object’s Layer Current	Click this icon, and then select an object to make its layer current.
Match Layer	Click this icon, select an object or objects whose layer assignment you want to change, press ↵, and then select an object whose layer you want to change to.
Previous Layer	Click this icon to switch to the previous current layer.
Isolate Object’s Layer	Click this icon, and then select an object to turn off all layers except the selected object’s layer.
Unisolate Objects Layer	Click this option to undo the action of the Isolate Object’s Layer icon.
Freeze Object’s Layer	Click this icon, and then select an object to freeze its layer.
Turn Off Object’s Layer	Click this icon, and then select an object to turn off its layer.
Lock Object”s Layer	Click this icon, and then select an object to lock its layer.
Unlock Object’s Layer	Click this icon, and then select an object to unlock its layer.

Keeping Track of Blocks and Layers

The Insert Block dialog box and the Layers palette let you view the blocks and layers available in your drawing by listing them in a window. The Layers palette also includes information about the status of layers. However, you may forget the layer on which an object resides. You’ve seen how the Properties Inspector palette shows you the properties of an object or layer. The List option menu bar also enables you to get information about individual objects.

Use these steps to see an alternate way to view the properties of a block:

The information in the Command Line palette, except the handle listing, is duplicated in the Properties Inspector palette when you select an object. But having the data in the Command Line palette gives you the flexibility to record it in a text file in case you need to store data about parts of your drawing. You can also use the Command Line palette to access and store other types of data regarding your drawings.

The Space property listed for the Tub block designates whether the object resides in Model Space or Paper Space. You’ll learn more about these spaces in Chapters 8 and 15.

Getting a Text File List of Layers or Blocks

With complex drawings, it can be helpful to get a text file that lists the layers or blocks in your drawing. You can do this by using the log-file feature in AutoCAD. At the Command prompt, enter LOGFILEMODE↵, and then enter 1↵. Type -LA↵ ?↵↵ (don’t forget the minus sign at the beginning of the LA command). Your list of layers appears in the Command Line palette. For a list of blocks, enter -Insert↵ ?↵↵. When you’ve obtained your list, close the log-file feature by typing LOGFILEMODE↵ 0↵.

Once the log-file feature is closed, you can use any text editor to open the AutoCAD log. To find the location of the log file, enter LOGFILENAME↵. The name and location of the log file appears in the Command Line palette. Typically, the location would look similar to the following:

The log file may be in a hidden folder, but you can get to it using the Go To Folder command. While in Finder, press -F-G. In the Go To Folder dialog box, enter the location of the log file, and click Go.

With the log-file feature, you can record virtually anything that appears at the Command prompt. You can even record an entire AutoCAD session. The log file can also be helpful in constructing script files to automate tasks. (See Bonus Chapter 1 on the book’s companion website for more information on scripts.) If you want a hard copy of the log file, print it from an application such as TextEdit or your favorite word processor.

The Bottom Line

Organize information with layers. Layers are perhaps the most powerful feature in AutoCAD. They help to keep drawings well organized, and they give you control over the visibility of objects. They also let you control the appearance of your drawing by setting colors, line weights, and linetypes.

Master It Describe the process of creating a layer.

Control layer visibility. When a drawing becomes dense with information, it can be difficult to edit. If you’ve organized your drawing using layers, you can reduce its complexity by turning off layers that aren’t important to your current session.

Master It Describe two methods for hiding a layer.

Keep track of blocks and layers. At times, you may want a record of the layers or blocks in your drawing. You can create a list of layers using the log-file feature in AutoCAD.

Master It How do you turn on the log-file feature?