Layer 0 has special Importance to blocks. When objects assigned :0 Layer 0 are used as parts of a block, those objects take on the characteristics of the layer on which the block IS Inserted. On the other hand, if those objects are on if layer other than Layer 0, they maintain their onqinal layer characteristics even If you Insert or change that block to another layer. For example, suppose the tub ISdrawn on the Door layer, instead of on Layer O. If you turn the tub Into a block and insert It on the Fixture layer, the objects the tub is compose of will maintain their assignment to the Door layer, although the Tub block IS assigned to the Fixture layer.
It might help to think of the block function as a clear plastic bag that holds together the objects that make up the tub. The objects inside the bag maintain their assignment to the Door layer even wlirle the bag itself ISassfgned to the Fixture layer.Au~toCADalso allows you to have more than one color or line type on a layer. For example, you can use the Color and Linetype buttons in the Change Properties dialog box (the Object Properties button on the Standard toolbar) to alter the color or line type of an object on layer O. That object then maintains Its assigned color and line type-no matter what its layer,assiqnment. ukewise, objects specifically assigned a color or line type are not affected by their mclusron Into blOCKS
Working on Layers
So far you have created layers and then assigned objects to those layers. However the current layer is still Layer 0, and every new object yeu draw will be on layer O. Here’s how to change the current layer.
1. Click the arrow button next to the layer name on the Object Properties toolbar. A drop-down list opens, showing you all the layers available in the drawing
Notice the icons that appear next to the layer names; these control the status of the layer. You’lileam how to work with these icons later in this chapter. lso notice the box directly to the left of each layer name. This shows you the color of the layer.
2. Click the Jamb layer name. The drop-down list closes, and the name Jamb appears in the toolbar’s layer name box. Jamb is now the current layer
3. Zoom in on the door and draw a S”line; start at the lower-right comer of thedoor and draw toward the right. Metrie users should draw a 13-on line.
4. Draw a similar line from the top-right end of the arc. Your drawing should look like Figure 4.13
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 what layer you are on as you draw. Now you will 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 will have to cut the line into three line segments, and then change the layer assignment of the segment between the jambs
1. In the Modify toolbar, click the Break tool or type br.J.
2. At the Se1ect obj ects: prompt, click the wall between the two jambs.
3. At the Enter second poi nt (or F for fi rst poi (It): type F. This
issues the first point option.
4. At the Fi rst poi nt: prompt, use the Endpoint Osnap override to pick the endpoint of the door’s arc that is touching the wall, as shown in Figure 4.13.
5. At the Enter second poi nt : prompt, type @.Jto signify that you want the second point of the break to be at the same location as the first point.
6. Click Break on the Modify toolbar, and then repeat steps 2 through 5, this time using the jamb near the door hinge location to locate the break point.
Next, you’ll change the Layer property of the line between the two jambs to the Ceiling layer. But instead of using the Properties tool, as you’ve done in earlier exercises, you’ll use a shortcut method.
1. Click the line between the door jambs to highlight it. . Iotice that the layer listing in the Properties toolbar changes to Wall. Whenc\ er you select an object to expose its grips, the Layer, Color, Linetype, and Line Width listings in the Properties toolbar change to reflect those propert ie-, ot the selected object..
2. Click the layer name in the Properties toolbar.p-down list appears.
3. Click the Ceiling layer. The list closes and the line YOLI selected changes to the magenta color showing you that it is now on the Ceiling layer. Also notice that the color list in the Properties toolbar also changes to reflect the new color for the line.
4. Press the Esc key twice to clear the grip selection.. otice that the layer returns to Jamb, the current layer.
5. Click the Zoom Previous tool in the Standard toolbar, or choose View >- Zoom >- Previous to return to the previous view.
In this exercise, you saw that by selecting an object with no command active, the object’s properties are immediately displayed in the Properties toolbar under the Layer, Color, and Linetype boxes. Using this method, you can also change an object’s color, line type, and line width independent of its layer. Just as with the Properties tool, you can select multiple objects and change their layers through the Layer drop-down list. These options in the Properties toolbar offer a quick way to edit some of the properties of objects
Now you’ll finish the bathroom by adding a sink to a layer named Casework.
1. Open the Layer Properties Manager dialog box and create a new layer called Casework.
2. When the Casework layer name appears in the Layer drop-down list, click the button labeled Current at the top of the dialog box.
3. Click the color swatch for the Casework layer, and then select Blue from the Select Color dialog box. Click OK to exit the Jialog box,.
4. Click OK on the Layer Properties Manager dialog box. Notice that the layer listing in the Properties toolbar indicates that the current layer is Casework.
Now you’ll add the sink. As you draw, the objects will appear in blue, the color of the Casework layer.
5. Click View» Zoom» All.
6. Click the Insert Block tool on the Draw toolbar, then click the Browse button in the Insert dialog box.
7. Locate the Sink file and double-click it.
8. In the Insert dialog box, make sure that the Specify On-Screen options in both the Scale and Rotation button groups are not checked, then click OK.
9. Place the sink roughly in the upper-right comer of the bathroom plan, then use the Move command to place it accurately in the comer,
Controlling Layer Visibility
I mentioned earlier that at times you’ll want to be selective about what layers you are working with on a drawing. In this bathroom, there is a door header that would normally appear only in a reflected ceiling plan. To turn off a layer so that it becomes invisible, use the Off button in the Layer Properties Manager dialog box.
1. Open the Layer Properties Manager dialog box by clicking the l.ayers tool in the Properties toolbar.
2. Click the Ceiling layer in the Layer drop-down list..
3. Click the lightbulb icon in the Layer drop-down list nextio the Ceiling layer name. You can also highlight the Ceiling layer in the Layer Properties Manager dialog box, then dick the check box labeled On in the Details group so that no check appears there. In either case, the lightbulb icon changes from yellow to gray to indicate that the layer is off.
4 Click the OK button to exit the Layer Properties Manager dialog box. When you return to the drawing, the header disappears because you have made it invisible by turning off its layer (see Figure 4.15
You can also control layer visibility using the Layer drop-down list on the Object Properties toolbar.
1. On the Object Properties toolbar, dick the Layer drop-down list.
2. Find the Ceiling layer and notice that its lightbulb icon is gray. This tells you that the layer is off and not visible.
3. Click the lightbulb icon to make it yellow.
4. Now click the drawing area to d~se the Layer drop-dJw; list, and the door header reappears
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 Layer Properties Manager dialog box offers some useful tools to help you find the layers you want fast. •
Now suppose you have several layers whose names begin with C, such as those layers quickly. You can click the Name button at the top of the layer list to sort the layer names in alphabetical order. Click the Name button again to reverse the order. To select thoSe layers for processing, click the first layer name that starts with C; then scroll down the list until you find the-last layer of the group and Shift+click it. All the layers between those layers will be selected. If you want to deselect some of those layers, hold down the Ctrl key while clicking the layer names you don’t want to include in your selection. Or Ctrl+click other layer names you do want selected. The Color and Linetypebuttons at the top of the list let you control what layers appear in the list by virtue of their color or line-type assignments. Other buttons sort the list by virtue of the status: On/Off, Freeze/Thaw, Lock/Unlock, and so forth. See the Other LAyer Options sidebar later in this chapter. Now try changing the layer settings again, turning off all the layers except and Ceiling and leaving just a simple rectangle. In the exercise, you’ll get a chance
to experiment with the On/Off options of the Layer Properties Manager dialog box.
1. Click the Layers button in the Object Properties toolbar, or on Format > Layers in the pull-down menus.
2. Click the topmost layer name in the List box; then Shift+cliclothe bottom-most layer name. All the layer names are highlighted.
3 .Ctrl+click the Wall and Ceiling layers to deselect them and thus exempt them from your next action
4. Click the lightbulb icon of any of the highlighted layer names or click the On check box in the Details section of the dialog box to clear the checkmark
5. A message appears warning you that the current layer will be turned off. Click OK in the message box. The lightbulb icons turn gray to show that the selected layers have been turned off
6. Click OK. The drawing now appears with only the Wall and Ceiling layers displayed (see Figure 4.17).
8. Click OK to return to the drawing.
In this exercise, you turned off a set of layers with a single click on a lightbulb icon. You can freeze/thaw, Jock/unlock, or change the color of a group oflayers in a similar manner by clicking the appropriate layer property. For example, if you click a color swatch of one of the selected layers, the Select Color dialog box appears, allowing you to set the color for all the selected layers.