No matter how many times you read this chapter or how carefully you study the AutoCAD documentation, you’ll occasionally run into plotting problems. You’re especially likely to encounter problems when trying to plot other people’s drawings, because you don’t always know what plotting conventions they had in mind. (Plotting conventions aren’t where spies meet; they’re a standardized approach to plotting issues.) Table 12-1 describes some of the more common plotting problems and solutions.
Table 12-1: Plotting Problems and Solutions
Problem
Possible Solution
Nothing comes out of the plotter (system printer driver).
Check whether you can print to the device from other Windows applications. If not, it’s not an AutoCAD problem. Try the Windows Print Troubleshooter (StartðHelpðContentsðTroubleshooting and Maintenance).
Nothing comes out of the plotter (nonsystem printer driver).
Choose FileðPlotter Manager, double-click the plotter configuration, and check the settings.
Objects don’t plot the way they appear on-screen.
Check for a plot style table with weird settings, or try plotting without a plot style table.
Objects appear “ghosted” or with washed-out colors.
In the plot style table, set Color to Black for all colors.
Scaled to Fit doesn’t work right in paper space.
Change the plot area from Layout to Extents.
The HP enhanced Windows system driver that came on the AutoCAD 2004 CD, and the available paper sizes aren’t right (for example, no architectural paper sizes).
On the Plot dialog box’s Plot Device tab, click the Properties button, and then the Custom Properties button (near the bottom), and then the More Sizes button to specify the standard and custom paper sizes. See the “Plotter Configuration” section under “Getting up close and personal with the Plot dialog box” earlier in this chapter for more information.
Chapter 13: Playing Blocks and Rasteroids Chapter 14: CAD Standards Rule
Chapter 15: Drawing on the Internet
Part Overview
In this part . . .
After you get the lines and text right, you may be justified in thinking that your work in AutoCAD is done. But AutoCAD enables you to do so much more! Blocks and external references help you manage data within drawings, between drawings, and across a network. If you plan to share drawings — whether among your own projects, with people in your office, or with folks in other companies, you need to think about consistency in presentation and drawing organization — in other words, CAD standards. The Internet is the biggest ongoing swap meet in human history, and AutoCAD offers some unique trading possibilities — and potential pitfalls — via e-mail and the Web. With the information in this part, you’ll be teaching AutoCAD how to give and receive in no time.
Introducing blocks, external references (xrefs), and raster images
Creating block definitions
Inserting blocks
Using attributes in blocks
Attaching and managing xrefs
Controlling xref paths
Attaching and managing raster image files
Chapter 6 shows you how to copy objects within a drawing or even to another drawing. That’s one way to use CAD to improve drafting efficiency. You can copy a DWG file and then modify it to create a similar drawing — an even better productivity-booster, as long as you’re in the habit of making similar drawings. But all of those are baby steps compared to the techniques that I cover in this chapter: treating drawings, parts of drawings, and raster images as reusable and updateable modules. If you want to make drafting production more efficient with CAD, then you want to know how to use blocks, xrefs, and raster files.
A block is a collection of objects grouped together to form a single object. You can insert this collection more than once in the same drawing, and when you do, all instances of the block remain identical, even after you change the bock definition. Although a block lives within a specific drawing, you can transfer copies of it into other drawings. You can add fill-in-the-blank text fields called attributes to blocks.
An external reference, or xref, is like an industrial-strength block. An external reference is a pointer to a separate drawing outside the drawing you’re working on. The referenced drawing appears on-screen and on plots as part of your drawing, but it continues to live as a separate document on your hard disk. If you edit the externally referenced drawing, the appearance of the drawing changes in all drawings that reference it.
A raster file (also called a bitmap file) stores a graphical image as a series of dots. Raster files are good for storing photographs, logos, and other images, whereas CAD vector files are good for storing geometrical objects such as lines and arcs, along with text and other annotations for describing the geometry. Sometimes it’s handy to combine raster images with CAD vector files, and AutoCAD’s IMage command makes the process straightforward.
Blocks, external references, and raster images enable you to reuse your work and the work of others, giving you the potential to save tremendous amounts of time — or to cause tremendous problems if you change a file on which other peoples’ drawings depend. Use these features when you can to save time, but do so in an organized and careful way so as to avoid problems.
Tip The way in which you use blocks and especially xrefs will depend a lot on the profession and office in which you work. Some disciplines and companies use these drawing organization features heavily and in a highly organized way, while others don’t. Ask your colleagues what the local customs are and follow them.
First, a little more block theory and then you can rock right into those blocks.
To use a block in a drawing, you need two things: a block definition and one or more block inserts. AutoCAD doesn’t always make the distinction between these two things very clear, but you need to understand the difference to avoid terminal confusion about blocks. (Maybe this syndrome should be called blockheadedness?)
A block definition lives in an invisible area of your drawing file called the block table. (It’s one of those symbol tables that I describe in Chapter 4.) The block table is like a book of graphical recipes for making different kinds of blocks. Each block definition is like a recipe for making one kind of block. When you insert a block, as described later in this chapter, AutoCAD creates a special object called a block insert. The insert points to the recipe and tells AutoCAD, “Hey, draw me according to the instructions in this recipe!”
Although a block may look like a collection of objects stored together and given a name, it’s really a graphical recipe (the block definition) plus one or more pointers to that recipe (one or more block inserts). Each time you insert a particular block, you create another pointer to the same recipe.
The advantages of blocks include:
Grouping objects together when they belong together logically. You can draw a screw using lines and arcs, and then make a block definition out of all these objects. When you insert the screw block, AutoCAD treats it as a single object for purposes of copying, moving, and so on.
Saving time and reducing errors. Inserting a block is, of course, much quicker than redrawing the same geometry again. And the less geometry you draw from scratch, the less opportunity there is to make a mistake.
Efficiency of storage when you reuse the same block repeatedly. If you insert the same screw block 15 times in a drawing, AutoCAD stores the detailed block definition only once. The 15 block inserts that point to the block definition take up much less disk space than 15 copies of all the lines, polylines, and arcs would.
The ability to edit all instances of a symbol in a drawing simply by modifying a single block definition. This one is the biggie. If you decide that your design requires a different kind of screw, you simply redefine the screw’s block definition. With this new recipe, AutoCAD then replaces all 15 screws automatically. That’s a heck of a lot faster than erasing and recopying 15 screws!
Blocks are great for convenience and storage savings within a drawing.
Warning Blocks aren’t as great for drawing elements used in multiple drawings, however, especially in a situation where several people are working on and sharing parts of drawings with one another. That’s because blocks, after they get into multiple drawings, stay in each drawing; a later modification to a block definition in one drawing does not automatically modify all the other drawings that use that block. If you use a block with your company’s logo in a number of drawings and then you decide to change the logo, you must make the change within each drawing that uses the block.
tip :External references enable you to modify multiple drawings from the original referenced drawing. You can find out more about external references in the section “Going External,” later in this chapter.
Tip: If all you need to do is make some objects into a group so that you can more easily select them for copying, moving, and so on, use the AutoCAD group feature. Type Group and press Enter to open the Group Manager dialog box. Then select some objects, click the Create Group button, and type a name for the group. Press Ctrl+H to toggle “group-ness” on or off. If you’ve toggled “group-ness” on, picking any object in a group selects all objects in the group. If you’ve toggled it off, picking an object selects only that object, even if it happens to be a member of a group.
Creating block definitions
To create a block definition from objects in the current drawing, use the Block Definition dialog box. (The other way to create a block definition is by inserting another drawing file into your current drawing as a block, which I explain in the next section.) The following steps show you how to create a block definition using the Block Definition dialog box:
Click the Make Block button on the Draw toolbar.
TIP:Layers matter when creating the objects that makes up a block. Block geometry created on most layers retains the characteristics, such as color and linetype, of those layers. But if you create a block using geometry on Layer 0, that geometry has no characteristics, such as color and linetype of its own; chameleon-like, it takes on the features of the layer into which it’s inserted. (If you don’t know what a chameleon is, ask a zoology teacher or a politician.)
Type the block definition’s name in the Name text entry box.
If you type the name of an existing block definition, AutoCAD replaces that block definition with the new group of objects you select. This process is called block redefinition. AutoCAD first warns you and then updates all instances of the block in the current drawing to match the changed block definition.
Tip To see a list of the names of all the current blocks in your drawing, pull down the Name list.
Specify the base point, also known as the insertion point, of the block, using either of the following methods:
Enter the coordinates of the insertion point at the X, Y, and Z text boxes.
Click the Pick Point button and then select a point on the screen. (In this case, use an object snap or other precision technique, as described in Chapter 4, to grab a specific point on one of the block’s objects.)
The base point is the point on the block by which you insert it later, as I describe in the next section.
Tip Try to use a consistent point on the group of objects for the base point, such as the lower-left corner, so that you always know what to expect when you insert the block.
Click the Select Objects button and then select the objects that you want as part of the block.
Click a radio button to tell AutoCAD what to do with the objects used to define the block: Retain them in place, Convert them into a block instance, or Delete them.
The default choice, Convert To Block, is usually the best, because it preserves the pointer to the block definition “recipe.” If you choose Retain instead, AutoCAD leaves the objects on the screen, but as separate objects with no relationship to the block definition.
Click a radio button to choose either Do Not Include An Icon or Create Icon From Block Geometry.
Go ahead and create the icon; it will help you and others find the right block to use later.
Specify the Insert units to which the block will be scaled in the Drag-and-Drop Units drop-down menu.
If and when the block is dragged from one drawing into another via the DesignCenter palette (see Chapter 4) or Tool Palette (described later in this chapter), the units you specify here and the units of the drawing you’re dragging into will control the default insertion scale factor.
Enter the block Description.
Now is the time to think like a database manager and enter a useful description that will identify the block to yourself and others.
Click OK to complete the block definition process.
If you don’t choose the Convert To Block or the Retain radio button, your objects disappear! AutoCAD has stored the block definition in the current drawing’s block table, however, and the block is ready to use. If you choose the Convert To Block radio button (the default), AutoCAD creates a block insert pointing to the new block definition — the objects look the same on-screen, but now they’re an instance of the block rather than existing as separate objects. If you choose the Retain radio button, the objects remain in place but aren’t converted into a block insert — they stay individual objects with no connection to the new block definition.
BLOCK and WBLOCK
The Block command, which opens the Block Definition dialog box, is great for use within a drawing, but what if you want to use the block definition in multiple drawings? The easiest method is to use DesignCenter to copy a block definition from one drawing to another, as described in Chapter 4.
Another method involves the WBLOCK and Insert commands. I don’t cover this method here, because it’s less intuitive than using DesignCenter. But you may hear AutoCAD drafters talk about “wblocking” part of a drawing. So that you can keep these block-y names straight:
The Block command creates a block definition from objects in the current drawing.
The WBLOCK command creates a new DWG file from objects in the current drawing, or from a block definition in the current drawing.
Technical Stuff You can include in a block definition a special kind of variable text object called an attribute definition. When you insert a block that contains one or more attribute definitions, AutoCAD prompts you to fill in values for the text fields. Attributes are useful for variable title block information (sheet number, sheet title, and so on) and symbols that contain different codes or call-outs. I describe how to create and use attribute definitions later in this chapter.
Tip Keep your common symbol drawings in one or more specific folders that you set aside just for that purpose. You may want use one of the following techniques to develop a block library of symbols that you use frequently:
Create a separate DWG file for each symbol (using WBLOCK, or simply by drawing each one in a new drawing).
Store a bunch of symbols as block definitions in one drawing and use DesignCenter to import block definitions from this drawing when you need them.
Inserting blocks
AutoCAD provides a number of ways to insert a block, but the most commonly used and most flexible is the Insert dialog box. Here’s the procedure for inserting a block:
Set an appropriate layer current, as described in Chapter 4.
It’s a good idea to insert each block on a layer that has something to do with its geometry or purpose:
If all the objects in the block definition reside on one layer, then it’s usually best to insert the block on that layer.
If the block geometry spans several layers, choose one of them to insert the block on.
Remember If any of the block definition’s geometry was created on layer 0, then that geometry will inherit the color, linetype, and other object properties of the layer that you insert the block on. It’s like the chameleon changing color to match its surroundings or a politician changing his position to match the day’s opinion polls.
Click the Insert Block button on the Draw toolbar.
Enter the block definition name or external filename by using one of the following methods:
Use the Name drop-down list to select from a list of block definitions in the current drawing.
Click the Browse button to select an external DWG file and have AutoCAD create a block definition from it.
You can use an external drawing to replace a block definition in your current drawing. If you click Browse and choose a file whose name matches the name of a block definition that’s already in your drawing, AutoCAD warns you and then updates the block definition in your drawing with the current contents of the external file. This process is called redefining a block — it automatically updates all the block inserts that point to the block definition.
Enter the insertion point, scale, and rotation angle of the block.
You can either click the Specify On-Screen check box in each area, to specify the parameters on-screen at the command prompt, or type the values you want in the Insertion Point, Scale, and Rotation text boxes.
Tip Check the Uniform Scale check box to constrain the X, Y, and Z scaling parameters to the same value (which in almost all cases you do).
If you want AutoCAD to create a copy of the individual objects in the block instead of a block insert that points to the block definition, click the Explode check box.
Click OK.
If you checked Specify On-Screen for the insertion point, scale, or rotation angle, answer the prompts on the command line to specify these parameters.
After you insert a block, all the objects displayed in the block insert behave as a single object. When you select any object in the block insert, AutoCAD highlights all the objects in it.
Tip Another way to insert a block is to drag a DWG file’s name from Windows Explorer and drop it anywhere in the current drawing window. AutoCAD then prompts you to choose an insertion point and optionally change the default scale factor and rotation angle. Similarly, you can drag a block definition’s name from the Blocks section of the DesignCenter palette and drop it into the current drawing wi
ndow. (Chapter 4 describes DesignCenter.) New for 2004 AutoCAD 2004 provides one additional way of inserting blocks: the new Tool Palette, which is described in Chapter 2. As is true of using Tool Palette for hatching (Chapter 11), you first must create and configure appropriate tools — that is, swatches. The easiest method is right-clicking a drawing in DesignCenter and choosing Create Tool Palette. A new page is added to the Tool Palette area containing all of the block definitions from the drawing that you right-clicked. Simply click and drag a tool to insert its corresponding block into a drawing. As with hatching, you don’t get the chance to specify a different insertion scale. You also can’t use all of AutoCAD’s precision tools to specify the insertion point precisely, so you may need to move the block into place after inserting it. I recommend that you first master the other block insertion methods described in this chapter — especially the Insert dialog box and DesignCenter palette. Then, if you find yourself inserting the same blocks frequently, conside
r creating a Tool Palette containing them. See “tool palette tools, adding” in the AutoCAD online help system for more information.
Warning Be careful when inserting one drawing into another. If the host (or parent) drawing and the inserted (or child) drawing have different definitions for layers that share the same name, the objects in the child drawing takes on the layer characteristics of the parent drawing. For example, if you insert a drawing with lines on a layer called Walls that’s blue and dashed into a drawing with a layer called Walls that’s red and continuous, the inserted lines on the wall layer will turn red and continuous after they’re inserted. The same rules apply to linetypes, text styles, dimension styles, and block definitions that are nested inside the drawing you’re inserting.
Tip If you need to modify a block definition after you’ve inserted one or more instances of it, use the REFEDIT command (Modifyð Xref and Block EditðEdit Reference In-Place). Look up “REFEDIT” in the AutoCAD online help system.
Attributes: Fill-in-the-blank blocks
You may think of attributes as the good (or bad) qualities of your significant other, but in AutoCAD, attributes are fill-in-the-blank text fields that you can add to your blocks. When you create a block definition and then insert it several times in a drawing, all of the ordinary geometry (lines, circles, regular text strings, and so on) in all of the instances are exactly identical. Attributes provide a little more flexibility in the form of text strings that can be different in each block insert.
For example, suppose that you frequently designate parts in your drawings by labeling them with a distinct number or letter in a circle for each part. If you want to create a block for this symbol, you can’t simply draw the number or letter as regular text using the mText or TEXT command. If you create a block definition with a regular text object (for example, the letter A), the text string will be the same in every instance of the block (always the letter A). Not much help in distinguishing the parts!
Instead, you create an attribute definition, which acts as a placeholder for a text string that can vary each time you insert the block. You include the attribute definition when you create the block definition (as I demonstrate in the “Creating block definitions” section earlier in this chapter). Then, each time you insert the block, AutoCAD prompts you to fill in an attribute value for each attribute definition.
Warning The AutoCAD documentation and dialog boxes often use the term attribute to refer indiscriminately to an attribute definition or an attribute value. I attribute a lot of the confusion about attributes to this sloppiness. Just remember that an attribute definition is the text field or placeholder in the block definition, while an attribute value is the specific text string that you type when you insert the block.
If you’ve worked with databases, the corresponde
nces in Table 13-1 between AutoCAD objects (blocks and attributes) and database terminology may help you understand the concept. Table 13-1: Attribute and Database Comparison AutoCAD Database
Block definition
Database table structure
Block insert
One record in the table
Attribute definition
Field name
Attribute value
Value of the field in one record
Attribute definitions
You use the Attribute Definition dialog box to create attribute definitions (clever, huh?). The procedure is similar to creating a text string, except that you must supply a little more information. Create attribute definitions with the following steps:
Change to the layer on which you want to create the attribute definition.
Choose DrawðBlockðDefine Attributes to run the ATTDEF command.
The Attribute Definition dialog box appears, as shown in Figure 13-4. Figure 13-4: The Attribute Definition dialog box.
Tip You rarely need to use any of the Mode settings (Invisible, Constant, Verify, or Preset). Just leave them unchecked. If you’re curious about what the modes do, use the dialog box help to find out more.
In the Attribute area, type the Tag (database field name), Prompt (user prompt), and Value (default value).
Warning The Tag can’t contain any spaces. The Prompt and Value fields may contain spaces.
In the Text Options area, specify the Justification, Text Style, Height, and Rotation.
The text properties for attribute definitions are the same as those for single-line text objects — see Chapter 9.
Choose the Pick Point button and choose an insertion point for the attribute definition.
An attribute definition’s insertion point is like a text string’s base point. Remember to use snap, object snap, or another precision tool if you want the eventual attribute values to be located at a precise point.
Click OK to create the attribute definition.
Repeat Steps 1 through 6 for any additional attribute definitions.
Tip you need to create a series of similar attribute definitions, create the first one using Steps 1 through 6. Then copy the first attribute definition and edit the copy(s) with the Properties palette.
Block definition containing attribute definitions
After you create one or more attribute definitions — and any other geometry that you want to include in the block — you’re ready to create a block definition that contains them. Follow the steps in the section, “Creating block definitions,” earlier in this chapter.
At Step 4 in the section, “Creating block definitions,” select any attribute definitions first before you select the other geometry. Select each attribute definition one-by-one (clicking on each attribute definition rather than selecting multiple attributes with a selection window), in the order that you want the attribute value prompts to appear in the Edit Attributes dialog box (see Figure 13-5). If you don’t select the attributes one-by-one, your block and attributes will still work, but the order of the attribute prompts in the Edit Attributes dialog box may not be what you want.
Technical Stuff You can use the Block Attribute Manager (choose ModifyðObjectðAttributeðBlock Attribute Manager) to re-order the attribute definitions in a block definition. You can also use this dialog box to edit other attribute definition settings, such as the prompt, text style, or layer. If you get tired of traversing four menu picks to get to this command, you can type the command name — BATTMAN (Block ATTribute MANager) — instead. I suppose it’s only a matter of time before Autodesk adds a ROBIN (ReOrder Block INsert) command. . . .
Insert a block containing attribute definitions
After you create a block definition that contains attribute definitions, you insert it just like any other block. Follow the steps in the section, “Inserting blocks,” earlier in this chapter. At the end of the steps, AutoCAD should display the Edit Attributes dialog box, shown in Figure 13-5. The dialog box contains one row for each of the attribute definitions and has any default values filled in. You simply edit the values and then click OK.
Tip The ATTDIA (ATTribute DIAlog box) system variable controls whether AutoCAD prompts for attribute values in a dialog box (ATTDIA=1) or at the command line (ATTDIA=0). If you insert a block and see command line prompts for each attribute value, type a value and press Enter for each attribute value. When you return to the Command: prompt, type ATTDIA, press Enter, type 1, and press Enter again. When you insert blocks with attributes in this drawing in the future, AutoCAD displays the Edit Attributes dialog box instead of prompting you at the command line.
Edit attribute values
After you insert a block that contains attributes, you can edit the individual attributes in that block insert with the EATTEDIT command (Enhanced ATTtribute EDIT — nothing to do with eating). Choose ModifyðObjectðAttributeðSingle and click on any object in the block insert. AutoCAD displays the Enhanced Attribute Editor dialog box with the current attribute values, as shown in Figure 13-6. The most common attribute editing operation is to edit the text value — that is, the text string that appears in the block insert. You can also change properties of the attributes, such as layer and text style.
Technical Stuff Many people use attributes in the way I’ve described so far — as fill-in-the-blank text fields in blocks. But attributes also can serve as data extraction tools. For example, you can export attribute values, such as part numbers and quantities, to a text file, and then import the data into a spreadsheet for analysis or reporting. The Attribute Extraction wizard (ToolsðAttribute Extraction) makes the process fairly straightforward. If you’re hungry to learn more, look up “EATTEXT (Enhanced ATTribute EXTtract) command” in the AutoCAD online help system.
Exploding blocks
The objects in each block insert act like a well-honed marching squadron: If you move or otherwise edit one object in the block insert, all objects move or change in the same way. Usually this cohesion is an advantage, but occasionally you need to break up the squadron in order to modify one object without affecting the others.
To explode a block insert into individual objects, click Explode (the firecracker button) on the Edit toolbar and then select the block insert. When you explode a block insert, AutoCAD replaces it with all the objects — lines, polylines, arcs, and so on — specified in the block definition. You then can edit the objects or perhaps use them to make more block definitions.
Warning Don’t make a habit of exploding blocks cavalierly, especially if you’re working in someone else’s drawing and aren’t sure why the objects are organized as blocks. Most people use blocks for a reason, and if you go around exploding them left and right, you’re likely to be treated the same way that anyone who blows up a lot of things gets treated.
Warning If you explode a block that contains attributes, the attribute values change back to attribute definitions. This usually isn’t the sort of change that you want. If you really need to explode the block insert, you’ll probably want to erase the attribute definitions and draw regular text strings in their place.
Purging unused block definitions
Each block definition slightly increases the size of your DWG file, as do other named objects such as layers, text styles, and dimension styles. If you delete (or explode) all of the block inserts that point to a particular block definition, then that block definition no longer serves any purpose.
You should run the PUrge command periodically in each drawing and purge unused block definitions and other named objects. Choose FileðDrawing UtilitiesðPurge to display the Purge dialog box, as shown in the figure. Click the Purge All button in order to purge all unused named objects in the current drawing.
In AutoCAD, an xref, or external reference, is not someone who used to be an official in a sporting contest. An xref is a reference to another, external file — one outside the current drawing — that you can make act as though it’s part of your drawing. Technically, a reference is simply a pointer from one file to another. The xref is the actual pointer, but the combination of the pointer and the external file often is called the xref.
Drawings that you include as xrefs in other drawings often are called child drawings. Drawings that contain pointers to the child drawings are called parent drawings. This family terminology gets a little weird when you realize that a child drawing can have lots of parent drawings that refer to it — apparently it’s the commune version of family relations. If you find such relationships odd, you can, like the AutoCAD online help system, refer to the parent drawing as the host drawing. I prefer the terms parent and child, in part because they’re easily extendable to describing more complex hierarchies, such as a parent drawing, which xrefs a child drawing, which in turn xrefs a grandchild drawing.
Xrefs have a big advantage over blocks: If you change a child drawing, AutoCAD automatically loads the change into all the parent drawings that reference the child drawing.
Technical Stuff AutoCAD loads all xrefs into the parent drawing each time the parent drawing is opened. If the child drawing has been changed, AutoCAD automatically incorporates those changes into the parent drawing.
New for 2004 When you open a drawing containing xrefs, AutoCAD 2004 displays a little symbol (looks like papers with a binder clip) on the right end of the status bar. This symbol alerts you to the fact that some of the things you see in the drawing are actually parts of other, xrefed drawings. If an xref changes while you have the parent drawing open (because you or someone else opens and saves the child drawing), the status bar xref symbol displays an External Reference Files Have Changed balloon notification. You can use the Reload option in the Xref Manager dialog box to show the updated xrefs. See the "Managing xrefs" section later in this chapter for details.
Another advantage of xrefs over blocks is that their contents aren’t stored in your drawing even once. The disk storage space taken up by the original drawing (that is, the xref) isn’t duplicated, no matter how many parent drawings reference it. This characteristic makes xrefs much more efficient than blocks for larger drawings that are reused several times.
But you can always buy more hard disk space, so the storage issue isn’t crucial. The key benefit of xrefs is that they enable you to organize your drawings in a modular way so that changes you make to a single drawing file automatically “ripple through” all the parent drawings to which it’s xrefed. This benefit is even greater on larger projects involving multiple drafters, each of whose work may be incorporated in part or in whole in the work of others.
Warning The automatic update feature of xrefs is a big advantage only if you’re organized about how you use xrefs. Suppose that an architect creates a plan drawing showing a building’s walls and other major features that are common to the architectural, structural, plumbing, and electrical plan drawings. The architect then tells the structural, plumbing, and electrical drafters to xref this background plan into their drawings, so that everyone is working from a consistent and reusable set of common plan elements. If the architect decides to revise the wall locations and updates the xrefed drawing, everyone will see the current wall configuration and be able to change their drawings. But if the architect absent-mindedly adds architecture-specific objects, such as toilets and furniture, to the xrefed drawing, or shifts all the objects with respect to 0,0, everyone else will have problems. If different people in your office share xrefs, create a protocol for who is allowed to modify which file when, and what communication needs to take place after a shared xref is modified.
Becoming attached to your xrefs
Attaching an external reference is similar to inserting a block, and almost as easy. Just use the following steps:
Set an appropriate layer current, as described in Chapter 4.
I recommend that you insert xrefs on a separate layer from all other objects. Note that if you freeze the layer an xref is inserted on, the entire xref disappears.
Choose InsertðXref Manager from the menu bar to start the XREF command.
Warning Don’t choose InsertðExternal Reference. This menu choice jumps ahead to Step 4, which will be confusing at this point.
Click Attach.
The Select Reference File dialog box appears.
Browse to find the file you want to attach, select it, and then click Open.
The External Reference dialog box appears.
Specify the parameters for the xref in the dialog box.
Parameters include the insertion point, scaling factors, and rotation angle. You can set these parameters in the dialog box or specify them on-screen, just as you can do when inserting a block, as described earlier in this chapter.
Technical Stuff You can choose the Attachment or Overlay radio button to tell AutoCAD how to handle the xref. The choice matters only if you create a drawing that uses xrefs, and then your drawing is in turn used as an xref. Attachment is the default choice, and it means that the xrefed file will always be included with your drawing when someone else uses it as an xref. Overlay, the other choice, means that you see the xrefed drawing, but someone who xrefs your drawing won’t see the overlaid file. By choosing Overlay, you can xref in a map, for example, to your drawing of a house, but not have the map show up when someone else xrefs your house drawing. (That person can xref the map, if need be.) I recommend that you use the default Attachment reference type unless you have a specific reason to do otherwise.
New for 2004 The AutoCAD 2004 Path Type drop-down list provides more flexibility in how the xref’s path gets stored. See the “Forging an xref path” section later in this chapter for more information. For now, I recommend that you choose Relative path instead of the default Full path.
Click OK.
The externally referenced file appears in your drawing.
Layer-palooza
When you attach or overlay an xref, AutoCAD adds new layers to your current drawing that correspond to the layers in the xrefed DWG file. The new layers are assigned names that combine the drawing name and layer name; for example, if you xref the drawing MYSCREW.DWG, which has the layer names GEOMETRY, TEXT, and so on, the xrefed layers will be named MYSCREW|GEOMETRY, MYSCREW|TEXT, and so on. By creating separate layers corresponding to each layer in the xrefed file, AutoCAD eliminates the potential problem I warned you about with blocks when layers have the same name but different color or linetype in the two drawings.
Technical Stuff AutoCAD also creates new linetypes, text styles, dimension styles, and block definitions for each of these items in the xrefed file — for example, MYSCREW| DASHED, MYSCREW|NOTES, MYSCREW|A-DIMS, and MYSCREW|LOGO.
Creating and editing an external reference file
To create a file that you can use as an external reference, just create a drawing and save it (or use the WBLOCK command to create a new DWG from geometry in the current drawing). That’s it. You can then start up a new drawing and create an external reference to the previous one. The xrefed drawing appears in your parent drawing as a single object, like a block insert. In other words, if you click any object in the xref, AutoCAD selects the entire xref. You can measure or object snap to the xrefed geometry, but you can’t modify or delete individual objects in the xref — you open the xref drawing in order to edit its geometry.
New for 2004 AutoCAD 2004’s new XOPEN command (ModifyðXref and Block EditingðOpen Reference) provides a quick way to open an xrefed drawing for editing. You just start the command and pick on any object in the xref. Alternatively, you can use the Open button in the Xref Manager dialog box to open one or more xrefs for editing. See the “Managing xrefs” section later in this chapter for more information.
Tip An alternative to opening the xrefed file when you need to edit it is to use the REFEDIT command (ModifyðIn-Place Xref and Block EditðEdit Reference). Look up “REFEDIT” in the AutoCAD online help system.
Forging an xref path
When you attach an xref, AutoCAD by default stores the xref’s full path (that is, the drive letter and sequence of folders and subfolders in which the DWG file resides, along with the filename). This default behavior corresponds to the Full path setting in the Path Type drop-down list, as shown in Figure 13-8. Full path works fine as long as you never move files on your hard disk or network and never send your DWG files to anyone else — which is to say, it almost never works fine!
At the other end of the path spectrum, the No path option causes AutoCAD not to store any path with the xref attachment — only the filename is stored. This is the easiest and best option if the parent and child drawings reside in the same folder.
New for 2004 If you prefer to organize the DWG files for a particular project in more then one folder, then you’ll appreciate AutoCAD 2004’s new Relative path option. This option permits xrefing across more complex, hierarchical folder structures, but avoids many of the problems that Full path can cause. For example, you might have a parent drawing H:\Project-X\Plans\First floor.dwg that xrefs H:\Project-X\Common\Column grid.dwg. If you choose Relative path, AutoCAD will store the xref path as ..\ Common\Column grid.dwg instead of H:\Project-X\Common\Column grid.dwg. Now if you decide to move the \Project-X folder and its subfolders to a different drive (or send them to someone else who doesn’t have an H: drive), AutoCAD will still be able to find the xrefs.
Technical Stuff When you use Relative path, you’ll see xref paths that include the special codes . and .. (single and double period). The single period means "this parent drawing’s folder" and the double period means "the folder above this parent drawing’s folder" (in other words, the folder of which the parent drawing’s folder is a subfolder).
You can report on and change xref paths for a set of drawings with the new AutoCAD 2004 Reference Manager. See Chapter 15 for more information.
Tip If all of these path options and periods have got you feeling punchy, you can keep your life simple by always keeping parent and child drawings in the same folder and using the No path option when you attach xrefs.
Managing xrefs
The Xref Manager dialog box includes many more options for managing xrefs after you attach them. Important dialog box options include:
List of external references: You can change between a List and a Tree view of your drawing’s external references just by clicking the appropriate button at the top of the dialog box. You also can resize the columns by dragging the column dividers or re-sort the list by clicking the column header names, just as in other Windows dialog boxes.
Detach: Completely removes the selected reference to the external file from your drawing.
Reload: Causes AutoCAD to reread the selected xrefed DWG file from the disk and update your drawing with its latest contents. This feature is handy when you share xrefs on a network and someone has just made changes to a drawing that you’ve xrefed.
Unload: Makes the selected xref disappear from the on-screen display of your drawing and from any plots you do of it, but retains the pointer and attachment information. Use the Reload button to redisplay an unloaded xref.
Bind: Brings the selected xref into your drawing and makes it a block. This is a good thing to do if, for example, you need to protect your drawing from changes that may be made to the xrefed file.
New for 2004 Open: Opens one or more xref drawings in separate drawing windows after you close the Xref Manager dialog box. After you edit and save an xref drawing, return to the parent drawing and use the Reload option in the Xref Manager dialog box to show the changes.
None of these options affects the xrefed drawing itself; it continues to exist as a separate DWG file. If you need to delete or move the DWG file that the xref refers to, do it in Windows Explorer.
Remember The fact that the xrefed drawing is a separate file is a potential source of problems when you send your drawing to someone else; that someone else needs all the files that your drawing depends on, or it will be useless to the receiving party. Make sure to include xrefed files in the package with your draw procedure.
AutoCAD LT AutoCAD (but not AutoCAD LT) includes an additional xref feature called xref clipping. You can use the XCLIP command to clip an externally referenced file so only part of it appears in the parent drawing. AutoCAD LT doesn’t include the XCLIP command, but if you open a drawing containing an xref that was clipped in AutoCAD, the clipped view will be preserved.
Blocks and xrefs are useful for organizing sets of drawings to use and update repeated elements . It’s not always clear, though, when to use blocks and when to use xrefs. Applications for xrefs include
The parts of a title block that are the same on all sheets in a project.
Reference elements that need to appear in multiple drawings (for example, wall outlines, site topography, column grids).
Assemblies that are repeated in one or more drawings, especially if the assemblies are likely to change together (for example, repeated framing assemblies, bathroom layouts, modular furniture layouts).
Pasting up several drawings (for example, details or a couple of plans) onto one plot sheet.
Temporarily attaching a background drawing for reference or tracing.
On the other hand, blocks remain useful in simpler circumstances. Situations in which you might stick with a block are:
Components that aren’t likely to change.
Small components.
A simple assembly that’s used repeatedly, but in only one drawing. (You can easily update a block in one drawing with the REDEFIT command.)
When you want to include attributes (variable text fields) that you can fill in each time you insert a block. Blocks let you include attribute definitions; xrefs don’t.
Everyone in a company or workgroup should be consistent about when and how to use blocks and xrefs. Check whether guidelines exist for using blocks and xrefs in your office. If so, follow them; if not, it would be a good idea to develop some guidelines. Chapter 14 discusses how to start such guidelines.
AutoCAD includes another xref-like feature: the ability to attach raster images to drawings. This feature is useful for adding a raster logo to a drawing title block or placing a photographed map or scene behind a drawing. A raster, or bitmapped, image is one that’s stored as a field of tiny points.
Most AutoCAD drawings are vector images. A vector image is an image defined by storing geometrical definitions of a bunch of objects. Typical objects include a line, defined by its two endpoints, and a circle, defined by its center point and radius. Vector-based images are typically smaller (in terms of the disk space they occupy) and more flexible than raster images, but also are less capable of displaying visually rich images such as photographs.
Raster images normally come into the computer from some kind of scanner that imports a blueline print, photograph, or other image. Raster images, such as company logos, can also be created in programs such as Photoshop.
Whether you’re doing your scanning yourself or having a service bureau do it for you, you need to know that AutoCAD handles most of the popular image file formats including the Windows BMP format, the popular Web graphics formats GIF and JPEG, the popular PCX and TIFF formats, as well as DIB, FLC, FLI, GP4, MIL, PNG, RLE, RST, and TGA.
Here are three scenarios to incorporate raster images in your drawing:
Small stuff: You can add logos, special symbols, and other small images that you have in raster files.
Photographs and maps: You can add photographs (such as a future building site) and maps (for example, showing the project location).
Vectorization: To convert a raster image into a vector drawing by tracing lines in the raster image, you can attach the raster image in your drawing, trace the needed lines using AutoCAD commands, then detach the raster image. (This procedure is okay for a simple raster image; add-on software is available, from Autodesk and others, to support vectorization of more complex images.)
Using raster images is much like using external references. The raster image isn’t stored with your drawing file; a reference to the raster image file is established from within your drawing, like an xref. You can clip the image and control its size, brightness, contrast, fade, and transparency. These controls fine-tune the appearance of the raster image on-screen and on a plot.
Warning When you attach raster images, you have to make sure that you send the raster files along when you send your drawing to someone else.
AutoCAD LT AutoCAD LT can open, view, and plot drawings containing attached raster images, but LT can’t do the attaching. Raster masters require full AutoCAD.
Attaching an image
Follow these steps to bring a raster image into AutoCAD:
Choose InsertðImage Manager from the menu bar or type IMage at the command line to start the IMage command.
Click the Attach button.
The Select Image File dialog box appears.
Browse to find the file you want to attach, select it, then click Open.
The Image dialog box appears.
Tip Click the Details button in the Image dialog box to see more information about the resolution and image size of the image you’re attaching.
Specify the parameters for the attached image in the dialog box.
Parameters include the insertion point, scale factor, and rotation angle. You can set these parameters in the dialog box or specify them on-screen, similar to what you can do with blocks and external references, as described earlier in this chapter. Use the quick dialog box help (click the question mark in the dialog box’s title bar and then click the area in the dialog box for which you want help) or click the dialog box’s Help button to find out more about specific options.
Warning Unfortunately, Autodesk didn’t add a Relative path option to raster images in AutoCAD 2004, as it did for xrefs. (See "Forging an xref path" earlier in this chapter.) Use the Retain path setting to choose between storing the entire path or no path. Retain path on corresponds to Full path, and off corresponds to No path.
Click OK.
The image appears in your drawing.
If you need to ensure that the raster image floats behind other objects in the drawing, select the raster image and then choose ToolsðDisplay OrderðSend to Back.
Technical Stuff The DRaworder command provides additional options for which objects appear on top of which other objects. If you need this kind of flexibility, look up “DRAWORDER command” in the AutoCAD online help system.
Managing images
You manage the images in your drawing with the Image Manager dialog box. It includes virtually the same options as the External References dialog box. Options include image files that appear in the current drawing, the ability to detach (remove) image references, and the ability to unload and reload images when needed. You can’t bind an image to your drawing; it’s an external file.
You can clip images so that only part of the image is displayed in your drawing. Choose ModifyðClipðImage and follow the prompts to clip the image. You can have multiple overlapping or distinct pieces of any number of images in your drawing, and only the parts you need are loaded into memory when you have your drawing open.
Tip Raster image files can be larger than DWG files; size can affect performance within AutoCAD, because the raster file loads into memory when you are working on your drawing. Some workarounds speed up operations:
Attach raster images late in the production process.
Create a lower-resolution version of the raster file, just large enough to create the desired effect in your drawing.
Use the Unload button in the Image Manager dialog box to temporarily disable an image without losing the attachment information.
If you’ve ever worked with other people to create a multi-chapter, visually complex, frequently updated text document, then you probably understand the importance of coordinating how everyone works on the parts of the document. Even if you’re someone who churns out documents from your one-person office or lonely cubicle, you probably try to ensure a reasonably consistent look and feel in similar documents. You employ consistent fonts, the same company logo, and the same paper size in most documents — or if you don’t, you probably at least think that you should!
CAD exacts similar demands for reasonable consistency, only more so:
Most companies would like to take pride in the clarity and consistency of their drawings. Sloppy drawings with randomly varying text heights and lineweights don’t reflect well on you and make the drawings harder to read.
CAD drawings that don’t conform with some logically consistent scheme usually are harder to edit and to reuse by others who work on the project and by you when you work on other projects.
This stuff is important enough in CAD that it has a special name: CAD standards. Those people compulsive enough to fret about it all the time and sadistic enough to impose their fretting on others also have a special name: CAD managers. This chapter won’t turn you into a CAD manager — a reassurance you’re probably grateful for — but it does introduce the most important CAD standards issues. This chapter also suggests some ways to come up with your own simple CAD standards, in case you’re going it alone and don’t have the benefit of a ready-made company or project CAD standards document to guide you. The chapter ends with an overview of AutoCAD tools that can help you comply with and check conformity to CAD standards.
Throughout this book, I emphasize things like setting up your drawings properly, drawing objects on appropriate and consistent layers, and specifying suitable text fonts and heights. These practices amount to conforming to a CAD standard.
You need to do these things if you work with or exchange drawings with others. If you don’t, several bad things will happen. You’ll be pegged as a clueless newbie by experienced drafters, who understand the importance of CAD consistency. Even if your ego can handle the contempt, you’ll make everyone’s work slower and more difficult. And if the project has electronic drawing submittal requirements, you may find that your client rejects your DWG files and demands that you make them conform to the CAD standards in the contract.
The aesthetics of CAD
Manual drafting veterans frequently complain that CAD drawings don’t look as good as the drawings that they used to create by hand. “Too ‘flat,’ too cartoonish, and inconsistent” are some of the refrains that you hear. These complaints are not just the whining of old-timers. Good manual drafters were justifiably proud of the appearance of their drawings. They focused on making the finished bluelines look sharp and read well.
When computers and CAD software got into the act, it became easy for CAD drafters to focus on the screen image and pay less attention to the plotted output. In the early days, CAD users struggled with a new way of making drawings and didn’t have as much time to make them look good. By the time that CAD became commonplace, a new crop of CAD users had grown up without the benefit of learning how to make good-looking drawings on paper.
There’s no reason that CAD drawings can’t look as good as manual drawings. It’s a matter of understanding the look that you’re after and caring enough to want to achieve it. If you see some especially clear and elegant printed drawings, find out who drew them and take that person out to lunch. You’ll probably learn some techniques that you can translate into making better CAD drawings. You may also gain new respect for the skills of those who made handsome and functional drawings with the simplest of tools.
Even if you work solo and don’t have any particular requirements imposed from outside, your own work will go more smoothly and look better if you adhere to a reasonably consistent way of doing things in AutoCAD. You’ll certainly find plotting easier and more predictable.
CAD standards originally grew out of a desire to achieve a graphical consistency on the plotted drawings that mirrored the graphical consistency on hand-drafted drawings. Before the days of CAD, most companies had manual drafting standards that specified standard lettering (text) sizes, dimension appearance, symbol shapes, and so on. Sometimes these standards were based on standard industry reference books, such as the Architectural Graphic Standards.
As CAD users became more sophisticated, they realized that CAD standards needed to incorporate more than just the look of the resulting plot. CAD drawings contain a lot more organizational depth than printed drawings — layers, screen colors, blocks, xrefs, text and dimension styles, and the like. If these things aren’t subject to a modicum of standardization, then different people who work on the same drawings or projects are likely to end up stumbling over — or throwing things at — one another.
The first job of CAD standards is to impose some graphical consistency on plotted output. CAD standards also encourage consistency in the way that people create, assign properties to, organize, and display objects in the CAD file.
If CAD standards are as important as I claim, you might expect that indus-tries would’ve settled on a standardized way of doing things. No such luck. Although the manual drafting conventions in many professions have carried over to some degree into CAD, a lot of the things that need standardization have been left to the imagination of individual companies, departments, or people. For example, you’ll find that different companies usually name layers differently and employ different schemes for mapping object screen color to plotted lineweight (see Chapter 12). In particularly disorganized companies, you’ll find that different drafters use different layers and color-to-lineweight. And in the worst cases, the same drafter will do these things differently in different drawings!
As you can imagine, this proliferation of non-standard standards makes sharing and reusing parts of CAD drawings a lot more difficult. You can at least minimize the pain within your own office by conforming to any existing CAD standards or, if there aren’t any, by encouraging the development of some. (Later in this chapter, I give some suggestions for how to get started.)
Industry standards
Professional, trade, and governmental groups in some industries have made an attempt to promulgate CAD standards for the benefit of everyone in the industry. For example, the American Institute of Architects (AIA), together with several professional engineering associations, published a CAD Layer Guidelines document, which has become part of a so-called National CAD Standard that’s now promulgated by the U.S. government’s National Institute of Building Sciences, or NIBS (see www.nationalcad standard.org). The International Organiza-tion for Standardization, or ISO (the acronym reflects the French ordering of the words), publishes ISO standards document 13567 (see www.iso.ch). This document, which comes in no fewer than three parts, attempts to pro-vide a framework for CAD layer standards in the building design industries throughout the world.
These documents may be useful to you in your search for standards, but they aren’t a panacea. The majority of CAD-using companies has ignored officially promulgated CAD standards, because these companies developed their own standards and practices years ago and are loath to change. That doesn’t mean that you can’t use the officially promulgated standards, but they won’t suddenly make you a part of some mythical CAD standards mainstream. Practical implementation of most official CAD standards in a specific company requires a generous amount of clarification, modification, and additional documentation. In other words, you don’t just buy the document and then get to work; someone needs to tailor it to your company and projects. Some of these officially promulgated CAD standards documents are shock- ingly expensive. Apparently these organizations haven’t learned that the way to make something popular is to post it on the Web for free!
Even if you’re lucky or perseverant enough to get a well-rounded set of CAD standards in your office, that may not be the end of it. CAD-savvy people from different companies who collaborate on projects often want to minimize the pain of inconsistency during drawing exchange. Although each company may have its own CAD standards house in order, there’s no way that all of those standards will be the same. Thus, one or more companies (often the lead consultant) may impose a set of project-specific CAD standards. Project-specific standards don’t necessarily need to be as detailed as a full-blown company CAD standards document, but depending on the project and the person who created the project-specific CAD standards, they might be.
The result of confusing muddle of industry practices, company CAD standards, and project-specific CAD standards is that you find yourself switching among different standards as you work on different projects. Before you start making drawings, find out whether any particular CAD standards apply. It’s a lot easier to start off conforming with those standards than to fix nonconforming drawings later.
If you are in a company or on a project without any CAD standards, put together at least a minimal set of guidelines. First, impose some consistency on plotted appearance and use of layers. If you make a few rules for yourself before you start, you’ll end up with drawings that are more professional looking and easier to edit, and more likely to be useful on future projects.
Tip A spreadsheet or word processing program is great for documenting your CAD standards decisions as they firm up. Many CAD standards components work best as tabular lists of layers, colors, and so forth. (See Tables 14-1 and 14-2 in this chapter for examples.) Use the cells in a spreadsheet or the tables feature in a word processor to organize your CAD standards documentation.
Before you start, make sure that you’re familiar with managing properties (Chapter 4) and plot styles (Chapter 12). You need a good understanding to make intelligent decisions about your plotting and layer standards. (If you want to make unintelligent decisions, don’t worry about those chapters!)
Plotting
If you plan to use color-dependent plot styles (most people do), develop a color-to-lineweight plotting chart like Table 14-1. If you choose the more logical but lonelier named plot styles approach, make a similar chart, with plot style names instead of color in the first column. (See Chapter 12 for information about color-dependent and named plot styles.) After you complete a plotting chart, create a plot style table (CBT file for color-dependent plot styles or STB file for named plot styles), as in Chapter 12.
Warning Your life will be easier — and your plotting chart will be shorter — if you limit yourself to a small portion of the 255 colors in the AutoCAD Color Index (ACI). The first nine colors work well for many people.
Tip If your work requires screened (shaded or faded-out) lines, extend the plotting chart to include a couple of additional AutoCAD colors. For each color, list the plotted lineweight and screen percentage ranging from 0% for invisible to 100% for solid black.
Layers
After you work out your plotting conventions, you’re ready to develop a chart of layers. A chart of layers takes more thought and work, and you’ll probably revise it more frequently than the plotting chart. Find a typical drawing from your office or industry and identify the things you’ll draw — such as walls, text, dimensions, and hatching. Then decide how you’d like to parse those objects onto different layers (see Chapter 4). Here are some rules:
Objects that you want to plot with different lineweights go on different layers. Assign each layer a different color, lineweight, or named plot style; let the objects inherit these properties from the layer.
Objects whose visibility you want to control separately go on different layers. Turn off or freeze a layer in order to make the objects on that layer, and only the objects on that layer, disappear temporarily.
Objects that represent significantly different kinds of things in the real world go on different layers. For example, doors should go on different layers from walls in an architectural floor plan.
As you make your layer decisions, you’ll develop a layer chart that resembles Table 14-2. If you use named plot styles instead of color-dependent plot styles, add a Plot style column to the chart.
Table 14-2: Sample Layer Chart
Layer Name
Color
Linetype
Use
Wall
5
Continuous
Walls
Wall-Belo
3
Dashed
Walls below (shown dashed)
Cols
6
Continuous
Columns
Door
4
Continuous
Doors
Text
3
Continuous
Regular note text
Text-Bold
7
Continuous
Large/bold text
Dims
2
Continuous
Dimensions
Patt
1
Continuous
Hatch patterns
Cntr
1
Center
Centerlines
Symb
2
Continuous
Annotational symbols
Nplt
8
Continuous
Non-plotting information
Warning The layer chart in Table 14-2 is simpler than the layer systems used by experienced drafters in most companies. The layer names in the table are based on names in the AIA CAD Layer Guidelines document mentioned in the “Industry standards” sidebar. That document recommends adding a discipline-specific prefix to each layer name: A-Walls for walls drawn by the architectural team, S-Walls for walls drawn by the structural team, and so on.
Technical Stuff For a discussion of CAD layer standards in architecture, engineering, and construction, see the article “AEC Layer Debate — AIA Sets the Standard” http://www.cadalyst.com/features/0601layer/0601layer.htm. If you enjoy reading articles like this one, you may be CAD manager material!
Other stuff
The following settings and procedures deserve some consistency, too:
Text styles. Decide on text fonts and heights and use them consistently. (See Chapter 9 for more information.)
Tip Manual CAD drafting standards often specify a minimum text height of 1⁄8 inch or 3 mm, because hand-lettered text smaller than that becomes difficult to read, especially on half-size prints. Plotted 3⁄32 inch or 2.5 mm CAD text is quite legible, but half-size plots with these smaller text heights can result in text that’s on the margin of legibility. Text legibility on half-size — or smaller — plots depends on the plotter resolution, the lineweight assigned to the text, and the condition of your eyes. Test before you commit to using smaller text heights, or use 1⁄8 inch or 3 mm as a minimum.
Dimension styles. Create a dimension style that reflects your preferred look and feel. (See Chapter 10.) Hatch patterns. Choose the hatch patterns that you need and decide on an appropriate scale and angle for each. (See Chapter 11.) Drawing setup and organization. Set up all of the drawings on a project in the same way, and use blocks and xrefs in a consistent fashion.
After you make standards, make sure that the plotted results are fine. You’ll undoubtedly revise and extend your standards as you go, especially on your first few projects. In time, you’ll find a set of standards that work for you.
