Yo~ may h’ave noticed the Freeze and’ Thaw buttons in the Layer Properties Manager dialog box. These options are similar to the On and Off buttons-however, Freeze not only makes layers invisible, it also tells Au’toCAD to ignore the contents of those layers wtien you use the All response to the Se1ect obj ects: .prornpt. Freezing layers can save time whqn you issue a command that regenerates a complex drawing. Thrs is because AutoCAD ignores objects on frozen layers’during Regen. You will get firsthand . experience with’ Freeze.and The Another pair of Layer Properties Manager options, Lock and Unlock, offer ‘a function similar to Freeze and Thaw. If you lock a layer, you can view and snap to objects on that layer, but yO:.Jcn’t edit those objects. This featur~ is useful when you are .working on a crowded drawing and you don’t want :”) ecooentally edit portions of it You can lock all the layers except those you intend to edit, and then proceed to work without fear of making accidental changes..
Three more options, Lineweight and Plot Style and Plot are new in AutoCAD 2000. Lineweight lets you control the width of lines in a layer. In prior versions of AutoCAD, you could only control line widths through the Style lets you assign plotter configurations
to specific layers. (You’ll learn more about plot styles, Plot lets you determine whether a layer gets p-rintecl:l hard-copy output. This can be useful for setting up layers you might use for layout purposes.
Taming an Unwieldy List of Layers
Chances are, you will eventually end up with a fairly long list of layers. Managing such a list can become a nightmare, but AutoCAD provides the Layer Filter dialog box to help you locate and isolate only those layers you need to work with. To use layer filters, click the Show drop-down list near the top of the Layer Properties Manager dialog box. This drop-down list contains a list of options described here in Table 4.2. See Using External References in Chapter 6 for information on Xrefdependent layers.
Now 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.
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 whose names contain the two characters FP signify floor plan layers. CP designa tes ceiling. information.
If you want to isolate only those layers that have to do with floor plans, regardless of their discipline, enter ??FP>tin the Layer Name input box. Youcan then give . this filter criteria the name Floor Plan by entering Floor Plan in the Filter Name input box. Then click OK to dismiss the Named Layer Filters dialog box. You can then pick Floor Plan from the Named Layer Filters drop-down list and only those layers whose names contain the letters FP as their third and fourth characters will appear in the list of layers. You can then easily turn all these layers off, change. their color assignment, or change other settings quickly, without having to wade through other layers you don’t want to touch. You can further create other named layer filters to isolate other groups of layers. AutoCAD keeps these filter lists for future use until you delete them using the Delete option in the Named Layer Filters dialog box
The other four input boxes near the bottom, Color, Lineweight, Linetype, and Plot Style, let you control what layers appear in the list by virtue of their settings as they relate to these four options. The six popup lists let you filter layers by virtue of the status: On/Off, Freeze/Thaw, Lock/Unlock, and so forth. See the Other Ltl!ler Options sidebar earlier in this chapter.
As the number of layers in a drawing grows, you will find layer filters to be an indispensable tooL But bear in mind that the successful use of the layer filters depends on a careful layer-naming convention. If you are producing architectural plans, you may want to consider the American Institute of Architects (AIA) layering guidelines.