Keeping Track of Layers and Blocks - Mastering AutoCAD for Mac - page 148

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.
CONTROLLING COLORS AND LINETYPES OF BLOCKED OBJECTS
Layer 0 has special importance to blocks. When objects assigned to layer 0 are used as parts of a
block and that block is inserted on another layer, those objects take on the characteristics of their
new layer. On the other hand, if those objects are on a layer other than layer 0, they maintain their
original layer characteristics even if you insert or change that block to another layer. For example,
suppose the tub is drawn on the Door layer instead of on layer 0. If you turn the tub into a block and
insert it on the Fixture layer, the objects the tub is composed of will maintain their assignment to
the Door layer even though the Tub block is assigned to the Fixture layer.
It may 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 while
the bag itself is assigned to the Fixture layer. This may be a bit confusing at first, but it should
become clearer after you use blocks for a while.
AutoCAD also enables you to have more than one color or linetype on an object. For example, you
can use the Color and Linetype pop-up lists in the Properties Inspector palette to alter the color
or linetype of an object on layer 0. That object then maintains its assigned color and linetype—no
matter what its layer assignment. Likewise, objects specifically assigned a color or linetype aren't
affected by their inclusion in blocks.
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:
1. First press the Esc key to clear any selections.
2. Click the Jamb layer name in the Layers palette, right-click, and select Set Current from
the shortcut menu. The Jamb layer in the layer list is highlighted indicating that Jamb is
now the current layer.
You can also use the Layer command to reset the current layer. To do this here, enter
-Layer ↵ S ↵ and then enter Jamb ↵↵.
3. Zoom in on the door, and draw a 5˝ line; start at the lower-right corner of the door and
draw toward the right. Metric users should draw a 13 cm line.
4. Draw a similar line from the top-right end of the arc. Your drawing should look like
Figure 5.13.
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 which layer
you're on as you draw.