Transcript
Aerospace Manufacturing/Engineering I Unit 1 Lecture Notes:
Autodesk will be used to represent Autodesk, Inc. and should always be understood to represent the registered trademark of the company Autodesk®. AutoCAD will be used to identify AutoCAD™, the basic product of Autodesk®, Inc. Microsoft will be used to represent Microsoft®, Inc. and should always be understood to represent the registered trademark of the company, Microsoft®. Windows will be used to identify Windows™, the basic product of Microsoft®, Inc. Throughout this document, the character "" indicates the [Enter] and [spacebar] keys.
Introduction In this first tutorial you will learn how to start AutoCAD, save a drawing, and a range of common drawing commands.
Starting AutoCAD Start AutoCAD by clicking on the AutoCAD icon on your desktop. If you prefer to use the Windows start menu, go to the Start button (bottom left), then move the mouse to Programs then Autodesk then "AutoCAD" and click on AutoCAD. A dialog giving various startup options will be displayed. Select the second option: "Start from Scratch" and click OK.
Figure 1 Generic AutoCAD screen. In Windows, a command line is not used. The command area in AutoCAD is critical. One of the keys to understanding how to use AutoCAD properly is to watch the command area. Using AutoCAD is like a conversation, with the command area acting as the program's half of the conversation. When AutoCAD has loaded, move the mouse until you see the crosshair cursor. You will use the cursor to make drawings.
The AutoCAD window has a number of important features: 1) The Quick Access Toolbar should be at the top left of the screen below the menus, it includes: File-New, File-Open, File-Save, Print, Undo, and Redo. 2) The Panel Buttons area is the next row. This area consists of three parts: a) Tabs i) The tabs are at the top of the Panel Buttons area. There are titles such as: Home, Insert, Annotate, Layout, etc. b) Command Panel i) These icons are what you choose to work on a drawing. When you choose a button, note that the command chosen will also be shown at the bottom of the screen in the command area. c) Panel Tiles i) Located at the bottom of the Panel Buttons area, these allow you to see additional commands available in each of the tabs, e.g.: in the Home Tab, the Draw Panel Tile has 13 commands in addition to the 7 commands shown on the Panel Button in Home. ii) If the button or Panel tab has a black triangle under or beside it, there are additional variations \to that command available when the triangle is picked. 3) Graphics area – this is the area where you draw - note the scroll bars and the axis label. 4) View Tabs – these tabs give access to different view of the current drawing. The "model" tab should be selected. 5) The command area – this is where you type commands. a) this area should be adjusted so it has three lines of text by default 6) The status area, at the bottom of the AutoCAD window, this includes the Coordinates Display, Drafting Settings, and the applications toolbar.
Command Entry Note: Not all commands are on the Menus and/or toolbars. Typically there are three ways of giving a command 1. Type the command using the keyboard - the command is displayed in the command area. 2. Select the command from a menu. 3. Select the command's icon from a toolbar. When you type a command in the command area the AutoCAD command will be written like: type: QSAVE This means : type the text (qsave) and then press the Enter key (or the space-bar). When I want you to select a command from a menu, it will look like: select File – Save This means : click on the 'File' menu and then 'Save' (which should be one of the items on the 'File' menu). When I want you to pick a command from a toolbar, I'll write: select Save AutoCAD also supports common shortcuts like Ctrl-S for Save. Despite all of the above, I'll probably use a combination of the above like: select File – Save (or type QSAVE) This gives the command to type, the menu options and shows what the toolbar icon looks like.
Draw a Rectangle Select Rectangle (or type rectang ), then type: 1,1 11,8.5
(These are absolute Cartesian coordinates) Hopefully AutoCAD drew a rectangle, which fits comfortably in the AutoCAD graphics area. If you can't see the rectangle, type z a (zoom all) - this instructs AutoCAD to redraw the view, "zooming" to show all the graphics on the drawing. The text you type is displayed in the command area at the bottom of AutoCAD's window. It is not necessary to move your cursor to the command area as long as the “Command” prompt is displayed.
Saving a Drawing Select the Save icon from the standard toolbar. The drawing has not been saved before, so AutoCAD will display the SAVE AS dialog box, select the appropriate Drive and Directory (for example: H:\CAD\Review), type the drawing name (for example TUT1), and then select "OK". Note that if you type SAVE , you actually get "Save As". The quickest way to save is to press Ctrl-S, this is the same as "qsave".
Draw some Lines We will now draw some more graphics and then save and exit AutoCAD. Type LINE Move the crosshair to near the bottom-left of the rectangle and click the left mouse button, then move the crosshair to the top-right of the rectangle and again click the left mouse button. Press to terminate the command, and then press again to re-start the command. If you press after you finish a command, the command is re-issued. Draw a line from the top-left to the bottom-right of the rectangle, and then press to end the command. Now type: QUIT This will save the drawing and exit AutoCAD - don't PANIC. You will be prompted to save the changes you've made - click OK. Instead of LINE, you can also type: L this is an "alias" - which is a short-cut. The exact positions of these lines is not important.
Coordinate Systems When specifying positions you can use Cartesian or Polar Coordinates. Cartesian coordinates are simply a X value, a comma, and a Y value, for example: 4,4. Polar coordinates are a Distance followed by the < symbol and an angle, for example: 10<25. Angles are measured in degrees, with 0 = East and 90 = North. Any of these numbers can have decimal values. AutoCAD is a three dimensional CAD system, so you can enter XYZ values instead of the XY values shown here. The positions specified above are "absolute coordinates", because they specify a particular position. AutoCAD can also use "relative coordinates" to specify a position relative to the current position, for example: @5.6,-3.4 and @16.32<62. Consider relative coordinates simply as distances.
Draw a "Diamond" The "polyline" used below is used to create a sequence of joined line segments, which become one object. Using the "line" command each line segment is a separate object. Select Polyline (or type: pline ) and then type: 2,2
absolute Cartesian coordinate @1.5<45 relative polar coordinate @1.5<135 @1.5<225 c "c" means "close" the shape. This should draw a "diamond" (a rotated rectangle) shape. If you make a mistake, you can undo the last line segment by typing: u.
Snap Modes It is often useful to be able to draw something from (for example) the end of another shape. AutoCAD has a large selection of "snap modes" for this purpose. The most commonly used snap modes are "Endpoint" (which snaps to the end of the selected graphics entity) and "Intersection" (which snaps to the intersection of two graphics entities). The easiest way to toggle the object snap (OSNAP) on or off is to push the F3 function key at the top of your keyboard. Another way is to click on "OSNAP" in Drafting Settings of the Status Area at the bottom of your screen directly below the command line. To see the various snap options "right-click" on "OSNAP" (in the status area) and select "Settings".
Draw an Arc Select Arc (or type ARC ), then select the midpoint snap mode (or type: MID ) and select the left side of the bottom of the "diamond" polyline you drew before. Then use the midpoint snap to enter points on the right side at the bottom and then the top of the polyline (see figure 2).
Figure 2
Arc construction.
Finally Draw a rectangle in the diamond shape, another diamond inside that rectangle, a circle inside that diamond and a horizontal and vertical line also inside the last diamond (see figure 3). Each shape should touch the Midpoints of the previous shape. Draw the rectangle by selecting rectang from the draw toolbar (or type rectang )
Alternatively select the circle icon and then type 2p then pick the points. HINT: To draw the circle, select Draw - Circle - 2 Points and then (using midpoint snap) pick opposite sides of the inner diamond. If you use the MIDpoint Snap Mode for each point, you should be able to draw the shapes without much trouble. If you make a mistake, press "Esc" (the "escape" key, located at the top-left of the keyboard). Then type U (the undo command).
Figure 3
Finished Tutorial 1 drawing.
Finishing up Save your drawing (press Ctrl-S) and then exit AutoCAD (select File - Exit). Peter, S , 2000. FBE Online Learning, Tutorial 1. Retrieved 23 Aug 2006 from http://www.fbe.unsw.edu.au/learning/autocad/ad2/T1/ and modified by Richard F. Marshall to conform to AutoCAD™ 2014 and the course Aerospace Manufacturing/Engineering Level 1 at Puget Sound Skills Center, Burien, WA, 98148
