138 Part II: Let There Be Lines
A load of linetypes
When you load a linetype, AutoCAD copies its linetype definition — a formula for how to create the dashes, dots, and gaps in that particular linetype — from the acad.lin (imperial units) or acadiso.lin (metric units) file into the drawing. (The files are acadlt. lin and acadltiso.lin, respectively, in AutoCAD LT.) The definition doesn’t automatically appear in other drawings; you have to load each linetype that you want to use into each drawing in which you want to use it. If you find yourself loading the same linetypes repeatedly into different drawings, consider adding them to your template drawings instead. (See Chapter 4 for information about templates and how to create them.) After you add linetypes to a template drawing, all new drawings that you create from that template will start with those linetypes loaded automatically.
Don’t go overboard on loading linetypes. For example, you don’t need to load all the linetypes in the acad.lin file on the off chance that you might use them all someday. The resulting linetype list would be long and unwieldy. Most drawings require only a few linetypes, and most industries and companies settle on a half dozen or so linetypes for common use. Your industry, office, or project manager may have guidelines about which linetypes to use for which purposes.
If you’re the technodweeb type and don’t mind editing a text file that contains linetype definitions, you can define your own linetypes or weed out the ones you’ll never use. Press F1 to open the online help window. Then choose Customization Guide Custom Linetypes.
As with all palettes in AutoCAD, you can leave the Layer Properties Manager open while you do other things in the drawing — unlike the dialog box method of stopping what you’re doing, opening the dialog box, making adjustments, closing the dialog box, and then resuming what you were doing. Also like other palettes, the Layer Properties Manager can be set to auto-hide itself to its title bar, to be either floating or docked, or to be anchored (do you get the sense that there are some AutoCAD programmers who’d rather be sailing?) to either side of the screen. If your computer has two monitors, you can drag the palettes to the second monitor.
Manipulating layers
After you create layers and draw objects on them, you can turn a layer off or on to hide or show the objects on that layer. In the Layer Properties Manager palette, the first three icons to the right of the layer name control AutoCAD’s layer visibility modes:
Off/On: Click the lightbulb icon to toggle visibility of all objects on the selected layer. AutoCAD doesn’t regenerate the drawing when you turn layers back on. On the other hand, frozen layers don’t regenerate while you’re working on the drawing. (We give you the lowdown on regenerations in Chapter 12.)
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Chapter 6: Manage Your Properties 139
Freeze/Thaw: Click the sun icon to toggle off visibility of all objects on the selected layer. Click the snowflake icon to toggle visibility on. AutoCAD regenerates the drawing when you thaw layers.
Lock/Unlock: Click the padlock icon to lock and unlock layers. When a layer is locked, you can see but not edit objects on that layer.
You can rearrange column order by simply dragging and dropping the column label to a new place. And you can right-click any column label to display a menu from which you can turn columns off and on.
Off/On and Freeze/Thaw do almost the same thing — both settings let you make objects visible or invisible by layer. You’ll probably find it makes no appreciable difference whether you freeze and thaw layers or turn them off and on.
You can turn layers off and on, freeze and thaw them, and lock and unlock them by clicking the appropriate icons in the Layer Control drop-down list on the Ribbon.
The state of your layers
Say you have a floor plan of a house that includes a layer showing the framing and another layer showing the wiring. You’d probably never show both of those elements on the same drawing, so you’d need to do some layer management when you showed your drawing to the framers or the electricians. Rather than turning a dozen layers off and a different dozen layers on when you want a different view into your drawing, you can save groups of layer settings as a named layer state. You can manage your layer states in the appropriately named Layer States Manager dialog box by clicking the Layer States Manager button in the Layer Properties Manager. You can also access the Layer States Manager directly by entering LAYERSTATES at the command line or choosing Manage Layer States from the Layer State drop-down list in the Layers panel.
AutoCAD fades objects on locked layers, giving you a really effective visual reference without confusing you about which layers might be locked or not. You can control the amount of fading by setting a nonzero value for the system variable LAYLOCKFADECTL. (See Chapter 26 for an explanation of system variables and check out the online help for specific info on this one.) You can turn off fading but retain the current setting for future use by adding a minus sign (–) in front of the fade value, or you can turn off the fading altogether by setting this value to 0.
If you find yourself using lots of layers, you can create layer filters to make viewing and managing the layer list easier. A group filter is simply a subset of layers that you choose (by dragging layer names into the group filter name or by selecting objects in the drawing). A property filter is a subset of layers that AutoCAD creates and updates automatically according to layer property
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