Tutorial 2 Dimension

1D2D - 1 - 1

Session 1

Introduction

The AutoCAD InterfaceAutoCAD's main window comprises the components shown in the followingfigure.

The graphics window is where AutoCAD displays your drawing and where youwork on your drawing. The text window displays a history of the commandsand options you have entered.

The cross-hairs are controlled by yourpointing device (usually a mouse) and areused to locate points and select objects inyour drawing. The status bar displays thecoordinate location of your cross-hairs andthe current settings of grid, snap, and otherdrawing aids.

For a 2-button mouse, the left button is thepick button, used for picking objects, menuitems, icons and dialogue box options. Theright button is the Enter button, the equivalent of using the Enter key on thekeyboard.

The middle button of a 3-button mouse can be customised to perform variousfunctions.

Mouse can also be replaced by light pens or digitiser pointers, some with up to24 configurable buttons.

Introduction

1D2D - 1 - 2Kamaruddin Mohd Nor

How to Access AutoCAD CommandsYou use AutoCAD by running commands using one of these methods:

• Choose a menu item - use the pointer to pick a menu item from themenu bar, then pick the command that you want from the listingdisplayed (cascade). Some menu items have further sub-menus.

• Click a tool on the toolbar - pick on the icon of the command from

the displayed graphic icons. You can preset AutoCAD to display ordisable the tooltips, i.e. small flags of information detailing thecommands of the icon.

• Enter a command at the Command: prompt - type in the command that

you want to execute, and press the Enter key or button.

Most commands that can be entered on the command line can be found on amenu or a toolbar, and most commands have additional choices, or options.Some commands display these options on the command line, while othersdisplay them in a dialog box. You enter command line options by typing at leastthe capitalized portion of the option name and then pressing ENTER. You setcommand options in a dialog box by clicking the option with the pointingdevice and then choosing OK.

Command: ‘zoom

Some of AutoCAD’s commands can be entered "transparently," that is, byplacing an apostrophe (‘) before them while another command is active. Forexample, while using the LINE command, you can enter 'ZOOM to changeyour drawing display without exiting the LINE command. When you exit the'ZOOM command, the LINE command remains active.

The last-used settings of most command options are "remembered" in systemvariables, which are stored in the drawing file. System variables determine thebehavior and default values for a command the next time you run it.

At the Command prompt, you can invoke the last-used command by pressingENTER. You can exit any command by pressing ESC.

Getting HelpAll of AutoCAD's documentation is online for quick access. You can get helpabout a command or procedure by selecting AutoCAD Help Topics from theHelp menu.

You can also get help about the current command, menu item, or tool by usingone of these context-sensitive methods.

1 Day AutoCADR14 - Introduction to CAD

1D2D - 1 - 3 CadWin Computer Consult

• For a command, enter 'help or press F1 while a command is active.• For a dialog box, choose the dialog box Help button or press F1.• For a menu, highlight the menu item and then press F1.

Starting A DrawingWhen you start AutoCAD, it prompts you with the Start Up dialogue whichpermits you to start the session in various ways:

Use a Wizard Let AutoCAD guide you to parametrically set upa drawing through two options, Quick andAdvanced

Use a Template Let you start a drawing based on a drawingwhich have been prepared with certainparameters, such as a drawing with a Title block.

Start from Scratch Start from a blank drawing which you can setyour own parameters.

Open a Drawing Open an existing (previously saved) drawing toedit.

If you open an existing drawing, all of the command and system variablesettings last used on that drawing are restored because this information is savedin the drawing file.

Introduction


The Setup WizardWhen you start a new drawing, there are a few settings you will want toestablish to assist you during the drawing process. You can use the SetupWizard to assist you in setting up the drawings, or do it manually from scratch.You can; however, you can change these basic settings at any time during thedrawing and editing process.

Units determines the measuring units you will use to draw objects:feet and inches, millimeters, miles, furlongs, and so on.

Scale determines the size of a unit when plotted on paper. InAutoCAD, you draw everything full scale in the units youset up, so you don't have to worry about scale until you'reready to plot your drawing.

Grid is to help you visualize units. It is a display of an array ofdots, called a grid, on your screen. The grid helps youvisualize the size of units on your screen if you increase ordecrease the magnification (zoom in or out) of yourdrawing.

Limits indicate to AutoCAD where in the drawing area's infinitespace you intend to draw. AutoCAD displays the grid onlywithin these limits. Limits also control some viewingoptions.

Snap enables you to locate and position points exactly on the gridor some subdivision of it. For example, you could display agrid with intervals of 4 millimeters but have points snap toexactly 1 millimeter, thus making it easier and faster to drawobjects accurately.

Once you have established these basic settings, you may want to use them forsubsequent new drawings. You can do this by saving the drawing as a templatedrawing. A template drawing is typically a blank drawing with preset settingsthat you use to start a new drawing.



Drawing ObjectsTo help you draw a variety of geometric shapes, AutoCAD has commands thatcreate many different types of objects. The following illustration portrays someof the objects you can create and the name of the command that creates them.

In addition to these simple geometric shapes, AutoCAD provides the followingcapabilities for creating more complex objects.

Polylines are complex multisegment lines that can contain both lines and arcs.You can control the width of individual segments in a polyline.

Hatching fills an irregular area or object with a line pattern. The hatch can beassociated with the object, so if you modify the object later, the hatchingautomatically adjusts. You can control the style, spacing, and angle of the hatchpattern.

Introduction


Fills are similar to hatching except that the area is filled completely. A region isa unique object type with which you can create enclosed areas by adding,subtracting, or finding the difference between several objects. Regions providean easy method to create complex enclosed areas for filling or hatching.

AutoCAD has several text creation and editing commands. Text can be createdas a single line or as a paragraph. You can control the text style, font, size,angle, and properties. You can attach invisible (or visible) text to objects thatdescribes the object. Such text is known as an attribute and can later beextracted into a list or report.

AutoCAD has extensive dimensioning, leader, and tolerancing capabilities. Youcan control every aspect of a dimension's appearance and behavior. Once youhave created a custom dimension you can save it as a named dimension style.Like hatching, a dimension can also be associated with the object it ismeasuring. If the object changes, the dimension is automatically updated.Following are some examples of standard AutoCAD dimension types.

Undoing MistakesIf you make a mistake while creating, editing, or viewing objects, you canalmost always undo what you have done. You can undo only the last operationor undo several previous operations. And, if you undo too much, you can evenundo the undo operation itself.



Drawing AccuratelyIn addition to grid and snap, AutoCAD has many tools that you can use tolocate points and create objects accurately.

One method is to specify coordinates. All drawings are superimposed on aninvisible grid, or coordinate system, with a horizontal X axis and a vertical Yaxis. A single unit in the coordinate system represents the unit that you choseto use for drawing (an inch, millimeter, kilometer, and so on). You canestablish grid and snap settings that match the units of the coordinate system orare some multiple or fraction of it.

As you draw, you can enter a coordinate to locate a point. For example, youcan draw a line by starting it at the 0,0 location in the coordinate system andend it at the -4,2 location, as shown above.

Other types of coordinate entry are also available. A relative coordinate isentered as the X and Y distance from the last point you located, and a polarcoordinate is entered as a distance and angle from the last point.

The Coordinate SystemAutoCAD has a fixed coordinate system called the World Coordinate System(WCS) and a movable coordinate system known as the user coordinate system(UCS). When you enter coordinates, you can specify which coordinate systemyou want to use.

To help you visualize the current location and orientation of the movable UCS,you can display the symbol known as the UCS icon. UCS icons in variousorientations are shown above.

The other precision drawing tools you can use are direct distance entry andtracking. To use direct distance entry, you move your pointing device toindicate a direction, and then you enter a distance. With tracking, you locate a

Introduction


point relative to previous points instead of specifying its absolute position inthe graphics area.

To gain accuracy without entering coordinates, you can set a snap interval,which will force the cross-hair to jump, or "snap," to the interval you set. If youset the interval to 2, the cross-hair snaps to points that are two units apart.Displaying a grid that matches, or is some multiple of, the snap value helps yousee where the snap points are in your drawing.

You can also specify precise points by snapping to specific points on anexisting object. For example, you can snap to the center point of a circle, themidpoint of a line, the intersection of two lines, and many other object snapoptions.

When you need to constrain lines to the horizontal and vertical axes, you canuse the Ortho (orthogonal) tool. You can also use construction lines (xline andray) to set up your drawing visuals.

Object PropertiesThere are certain properties that are associated with all objects that you createin AutoCAD.

The style of line, or linetype, that an object is drawn in can be set to manydifferent styles, such as solid, phantom, center, dotted, and hidden. You cancreate your own dashed lines or more complex linetypes like the following.

You can set the color of objects you create to help you visually distinguishthem. When you print or plot your drawing, you can map a color to a specific



pen or line weight on the plotter. By standardizing a specific color scheme, youwill know that objects displayed in a given color will have a heavier line weightwhen output to paper.

Layers in AutoCAD are equivalent to overlays in manual drafting. Layersprovide an efficient way to organize drawing elements into logical groupings.You can name each layer and assign a color and linetype to it as dictated byindustry, job, or company standards.

In addition to helping you organize your drawing, layers also give you greatercontrol over the graphic display. You can turn off one or more layers toremove details as you work and then turn them on again when you plot.

Creating Standard SymbolsMost engineering and architectural drawings contain repetitive symbols. InAutoCAD, you create such symbols by combining several objects together intoa single object called a block. The block can then be inserted into your drawingmany times as a standard symbol. If you change the master block definition, allinstances of the block, or block references, are automatically updated (unlessyou have modified a block reference in some way).

A block definition can be saved either with the current drawing or as a separatedrawing file. If you want to insert the block into other drawings, you need to

Introduction


save the block as a separate drawing. After you insert a block into yourdrawing, you can disassemble it to its individual components again byexploding it.

All or part of another drawing can be inserted or overlaid on your drawing bycreating an external reference, or xref, to another drawing. An xref creates apointer to another drawing but does not add that drawing's data to yourdrawing. The main advantage of using xrefs is that a single master drawing canbe referenced by many drawings. When you modify the master, all the drawingsthat reference it are automatically updated.

Similar updating capabilities are available when you use Windows' objectlinking and embedding (OLE) to link a file from another application to yourAutoCAD drawing. The inverse is also possible; you can insert all or part of anAutoCAD drawing into a file created by another application.

Viewing and EditingOnce you have created objects in your drawing, you can use AutoCAD'sediting and viewing tools to modify objects and display your drawing in variousways.

Viewing your DrawingWith AutoCAD you can change the magnification of the drawing on yourscreen. You can increase magnification (zoom in) for close-up work ordecrease magnification (zoom out) to view the entire drawing.

To view another section of your drawing, you can pan the drawing, whichshifts the display without changing magnification. You can pan with the PANcommand or with the scroll bars.



You might have several views showing different areas of your drawing that youwant to switch between. AutoCAD can "remember" a view by name so thatyou can recall it later.

You can view different parts of the drawing simultaneously by splitting thescreen into stationary windows known as tiled viewports. You can control thedrawing display in each tiled viewport independently by panning, zooming, orchanging the viewing angle.

Editing your DrawingAfter you create objects in your drawing, you will usually need to modify themin some way. AutoCAD provides a variety of editing tools that minimize thetime it takes to make corrections.

Often, you may need to move an object to another location, align it with otherobjects, or change its rotation. The MOVE, ALIGN, and ROTATE commandsprovide this capability.

Introduction


If you need to duplicate objects in your drawing, there are several ways toaccomplish this. You can duplicate an object and place copies at multiplelocations in your drawing. You can create a block and insert it multiple times.If you need a reverse copy of an object, you can create a mirror image. Youcan also create an array, which copies an object into an orthogonal or circulargrid pattern.

A capability similar to copying is the ability to offset an object. An offset is acopy of an object in which all of the line segments are copied a given distancefrom the original object.

If you decide an object must be longer in one direction, you can stretch it.Another form of stretching can be performed on lines: you can trim or extendthem to a specific length or until they intersect another object.

You can also move, copy, mirror, stretch, and rotate objects in a singleoperation using grips. This is done by selecting an object first (before entering acommand) and then using the grips displayed and grip options to modify theobject.

Another way you can edit objects is to chamfer (bevel) or fillet (round) theintersection of lines and arcs.

You can remove objects from your drawing at any time by erasing them.



Looking up Drawing DataYour AutoCAD drawing contains many types of data that you can look up.You can list the properties of an existing object, like its color, layer, orlinetype, and you can copy those properties and apply them to another objectusing the Match Properties command. You can calculate an area that youdefine or that is enclosed by an object. The distance and angle of a line orpoints can be also be calculated.

Command: _area<First point>/Object/Add/Subtract: A<First point>/Object/Subtract: O(ADD mode) Select objects: (pick the external circle)Area = 20611.9894, Circumference = 508.9380Total area = 20611.9894(ADD mode) Select objects: (Enter)

Preparing Your Drawing for PlottingThe last step in completing a drawing is printing or plotting it on paper. Beforeprinting or plotting you may want to lay out several views of your drawing thatwill appear on the final plot.

Setting Up A Drawing EnvironmentAutoCAD provides two drawing environments for creating and laying out yourdrawing: model space and paper space. You usually create your drawing, calleda model, at full scale in an area known as model space without regard to thefinal layout or size when you plot it on paper. You can subdivide your graphicdisplay into smaller model spaces, known as tiled viewports, where you canview your drawing from different viewing angles.

When you're ready to print, you can arrange the elements of your drawing onyour "sheet of paper" in paper space. Conceptually, paper space represents thepaper on which you plot. You can also configure the paper space with one ormore viewports, this time called floating viewports, each showing a differentarea or view of the drawing.

A viewport can display a view of your drawing at any scale and from anyvantage point. In paper space, you can move these viewports to create thelayout you want for plotting.

Introduction


Printing and Plotting your DrawingYou can output your drawing to either a printer or a plotter. If you are using aWindows system printer you generally don't need to do any preparation toprint. When you use a plotter, however, you need to configure several things:the plotter driver, output ports, pen configuration, and so forth.

When you print or plot, you can control the area of the drawing that you areplotting and its scale, rotation, and location on the paper. You can also controlthe pens that are used to plot objects drawn in each color and the weight of theline. Linetypes can also be substituted at the time of plotting.

Metric Paper Sizes

It is always a good idea to always remember the paper size conventions thatyou are using for the drawings. This will help you maintain drawing layout andhardcopy productions similar to the manual drafting standards. The metricsystem uses the A-type paper sizes, shown above with their sizes in millimeters.

Copyright Notice: The notes on these introduction pages are compiled andedited directly from sources within the AutoCAD®

Release 14 software package.

Documents

Tutorial 2 Dimension