AutoCAD Tutorial : Session One

AutoCAD commands are normally in either italics or boldface, but those in boldface are commands you are being instructed to carry out as part of the tutorial. Those in italics are suggestions or other references to commands. Lines beginning with an asterisk contain instructions to carry out a process of some kind. We are probably not entirely consistent in these matters, but . . .

As the tutorial progresses, some of the instructions will become less complete, on the assumption that you have learned a good deal about the system and can figure out more on your own. If you find an incomplete description of a command, please check to see if a fuller description was provided earlier. We recommend that you work with the tutorial and otherwise work with AutoCAD for more than an hour at a time during your first week and that you try to work with the system daily for the first week. You will find that your comfort level increases and you will relax with the system more readily if you work with the system frequently and for longer stretches of time during the learning period.

Please note that we are instructing you to use keyboard commands exclusively. Virtually every one could be initiated with a menu selection instead. Feel free to experiment with other ways to activate the commands we've chosen; they should work the same whether started from the keyboard or a pull-down menu. We did choose to have you type commands, though, because we think that it's quicker in the long run - and because the keyboard commands are consistent from one version of AutoCAD to another, while the pull-down menus are not always consistent.

Finally, we have found through experimentation that you should read all of each command procedure before beginning to carry out the instructions. Sometimes things seem unclear but are quite obvious if you know the full sequence at the beginning; at other times, the first steps will be puzzling if you aren't aware of the ones to follow. In any case, the point is not to do the exercises; it is to understand how to use the commands.

Session One:

Basic Drawing commands - units, limits, redraw, regen, control-c (escape key), help, line, zoom, id, endpoint, F2, erase, undo, pline, qsave, 3dpoly, distance, move, copy, point specifying processes, text, editing objects, mslide, end

First begin AutoCAD.

* When the system is ready, type new and a carriage return (hereafter ) and give your file a name. The name you choose is up to you, but we recommend a six-character name that will leave two characters (in a DOS, eight-character naming system) to identify different versions of the file. Thus, if you have any concerns about your progress in a given session, you can save the file under a new but related name and preserve the file from the prior session. AutoCAD automatically appends the .dwg extension to the file name.

Please note that there is now an icon with arrows in the lower left corner of the drawing window. The arrows indicate the directions for the x and y axes. There is also a W in it, indicating that you are working in the world coordinate system. Don't worry about that for now, but do note that the direction of the arrows can change as you manipulate the drawing, always indicating the x and y axes.

UNITS

Before starting a drawing, you must determine the units with which the drawing will be made, the ways numbers are displayed, and some other drawing procedures.

* Type units and . You will then be asked, in sequence, to choose:

* the measuring system (choose decimals - the system does not care what the base unit is, only whether it will be divided into decimals or 12ths or whatever - for our purposes the base unit is the meter),

* the number of decimal points to be displayed (choose 3 so that we are dealing with millimeters as the smallest unit displayed),

* the way angles will be measured (choose decimal degrees),

* the number of fractional places to be displayed for angles (choose 4),

* where the zero angle will be (choose North- the default is East),

* and whether you will measure positive angles as clockwise (choose yes).

After the last choice, you should see your drawing window again. But, on some DOS systems, that won't happen, and you will still be looking at the text screen. If so, press the F1 key to return to the drawing screen.

LIMITS

Another set-up process is setting the drawing limits. You don't have to set limits, but if you do set them, you can protect yourself from erroneously drawing things outside those limits. Setting limits also makes it easy to call up in your viewing window only that area defined by the stated limits.

* Type limits and and then give two sets of coordinates (x and y only) for the limits.

* Type -10,-10 and for the lower left corner.

* Type 15,15 and for the upper right corner.

* To make the limits active, type limits and again and choose on and . (With limits set but turned off, you can draw outside the limits, something you may want to do on occasion.) Now you will be unable to draw anything with an x or y value greater than 15 or smaller than -10.

REDRAW, REGEN, Control-C (escape key)

Note that the commands redraw and regen (regenerate) can be used at any time to refresh the screen; these commands remove the marks left from various editing processes. Redraw simply draws the same image again; regen requires the system to start from the database and reconstruct all parts of the model from scratch. Feel free to use these commands at any time. Also note that control-c will interrupt most processes. If you find yourself in the midst of something you want to stop, just type control-c - but in Release 13, use the escape key instead. (It's easy to type control-x instead of control-c; if you do type control-x the word delete may appear - depending on the version you're using. That does not mean that a part of the drawing has been deleted; control-x should just cancel a command that has been partially typed.)

Please note the use of the term model in the foregoing. A CAD model is more than a drawing, since you can zoom in and change viewing angles; so we will try always to use the term model to refer to the computer version of your work.

HELP

If, for any reason, this tutorial is not crystal clear -- perish the thought -- you can type help (or ?) and to get AutoCAD's help menu.

LINE

* To begin our drawing, type line (or just l) followed by a space or .

(AutoCAD treats a space as equivalent to a ; so from here on, we will use to indicate either. Note, in addition, that AutoCAD will treat a or a space at the command prompt as a restatement of the last command. Thus, when we complete this command, we could use the key to start the line drawing process again. That can be very useful.)

Since the space is equivalent to the , we will continue to use a convention of command and or command to indicate that you should type first the command and then the , with no space between. Obviously, you must be sure not to type a space by habit.

* Type 3,4,0 to specify the starting point of the line.



* Enter the ending point 6,5,0.

* Then type to end the command.

Let's make another line that meets the first one at its point of origin.

* Type line (or l) and use the mouse to mark the starting point of a new line. Start it just at the beginning of the last line. Use the mouse to select the point for the end of the line (wherever you like) and type to terminate the command. Now you have two lines that meet. Or do you?

ZOOM, ID, Endpoint

* Type z (for zoom). You have a series of options available, but if you just click with the mouse or type coordinates (x and y only), the system will assume that you mean to define a window for the new view. The first point needs a diagonally opposite one to define the window; again, either a mouse click or another set of coordinates. (There is an AutoCAD system variable that will change the window selection process to click-and-drag, but this is not the time to worry about changing system variables.)

* Enter the coordinates 2.6,4.6 and then 3.4,3.6 to define a zoom window with its diagonally opposite points (you could do that with the mouse, but I want you to have zoomed in very close for this). You have now zoomed in very close and can see that you did not really get the second line to begin precisely where the first one did. You can move the crosshairs from one point to the other to see where the two points are; just look at the coordinate window at the top of the drawing window to see your location. Better yet, let the computer tell you precisely where the end of each line is located.

* Type id and then type endpoint. The cursor will become the shape of a small box. Move your mouse to put the box around the end of one of the lines and click to select it. The system will display the coordinates of the end of the line - using endpoint tells the system that you want it to find the end of a line, the corner of a rectangle, etc., not just a point in space.

( Do the same for the other line - type id, endpoint, and select the end of the line. Check the difference. Note that asking for the identification of a point requires that you specify that you want the endpoint of the line (you could also specify midpoint or center). Otherwise, you would simply receive the coordinates of the point where the cursor lay, not the end of the line. You should be able to use your mouse to indicate that you will pick an endpoint of a line, not just the point where the cursor lies. Try using the right button on your mouse. It should cause a pop-up menu to appear, with endpoint being one of the first words shown. If that works, try it the next time you need to use endpoint. When you're ready to choose the point, select the right mouse key to pop up the menu, select endpoint, and then pick the point you want. It's much quicker than typing endpoint.

F2 (or F1 in DOS versions)

* You won't be able to see both sets of numbers at once with the small text area at the bottom of the drawing screen; so type the F2 key to call up the full-text screen. (You may have to use the F1 key if you are using a DOS version of AutoCAD. The F1 key was the standard until Windows, but all Windows programs are supposed to use F1 for help. From this point on, the tutorial will instruct you to use the F2 key on occasion, but you should understand that to mean either the F2 key or the F1 key, depending on the system you are using.) The full text screen will show much more text, including the numbers you asked for.

* After you've compared them, type F2 again to return to the model.

This exercise should have demonstrated that you can't rely on your hands and eyes for precision. So it is usually best to use the keyboard to enter point coordinates in your model directly from the keyboard. Or you can specify the use of an existing point in the model with a command such as endpoint.

Let's now get back to the original view and delete the lines we just drew. We only drew them to make the point that your model may not necessarily be as precise as it appears on screen.

* Type z and p to zoom to your previous view.

ERASE

* Erase the two lines by typing erase and selecting both lines with the mouse. Then type to complete the command.

Now we'll start our model again.

* Type l to start a line.

* For point one, type 3.8,8,0 - these are the x-, y-, and z-coordinates of the first point of the line. You can always enter coordinates directly from the keyboard like this.

* For point two, type 5.75,8,0, the coordinates for the second point.

* Oops. you should have typed 6.8,8,0.

UNDO

* Type u now to undo the last choice. (In a sequence like this, you can keep typing u to undo all but the very first point in the sequence, but you may see the markers on the screen indicating the points you chose. Typing redraw after you finish with the line will remove them.)

* Now, for point two, type 6.8,8,0.

* For the third point, you are going to tell the system where the point is to be, not in absolute terms as you've done thus far, but relative to the second (last) point. Type @0,-.75,-1 to indicate that the new point has those x-, y-, and z-coordinates relative to the prior point, i.e., the same x-value as point two, a y-value .75 units less than that of point two, and a z-value 1 unit less. So point three lies at 6.8, 7.25, -1.

* For the fourth point, you will use what are called polar coordinates to specify the position of the point. This type of specification is also based on the previous point. Type @3<270 to indicate that the new point is 3 units distant and at a 270-degree angle from the third point; the <> to indicate that the figure should close onto its first point.

Now you have drawn a simple rectangle; we will call it Rect. B. You should note that the third and fourth points have elevations different from the elevation of the first two points. That does not show in a plan view, but it will be obvious in a 3D view.

* Type zoom or z to zoom in on the figure. You can make a window with your mouse to indicate the zoom window or give it coordinates, as we did before.

* Use the coordinates 3.3,9 for the upper left corner and 7,6 for the lower right corner.

PLINE

* To draw a similar figure with a different process, type pline. This will make what AutoCAD calls a polyline.

* For the first point, type 3,8,0.

You can see that there is a problem here. The new figure does not show in the drawing window. So you can do what AutoCAD calls a transparent zoom, a zoom in the middle of a command without interrupting the command. Type 'z and then type .2x to indicate that you want the new display to reduce the size of the drawing to one fifth the current size. The apostrophe tells the system that you are invoking a command transparently. Now you can see enough to continue.

* For the second point, type @.75,0.

* For the third point, type @0,-6.

* For the fourth point, type @.75<270.

* Then type c to close the figure.

The process is not different from the process you used to draw a line, and we have another rectangle that we will call Rect. A. The difference is that AutoCAD will treat all the pieces of a polyline as parts of a single entity in the model. If you drew the same figure with the line command, each line segment would be treated as a distinct entity. If you want to move or copy a line with many individual segments, it should be drawn as a polyline so that it can be treated as a single item.

Now your drawing is a bit small; so type

zoom extents (or z e - or z space-key e space-key) to indicate that the drawing window should include all of the pieces of the model. The model will be fitted tightly to the lower left corner of your window. (If we asked for the system to zoom to all of the drawing, the window would include all the area within the drawing limits, regardless of how much or how little had been drawn.)

During the course of these exercises you may need to zoom in to make your image larger. Feel free to do that at any time. But, since I will be trying to keep track of your drawing progress, please return to the previous image size after you zoom in. Return to the previous image size by typing zoom previous

You will see that this figure is another rectangle. However, for the second rectangle we gave all the points the same value for z; we entered a z-value only once, for the first point, because standard AutoCAD polylines must have the same elevation throughout. Once we supplied a z-value with the first point, all successive z-values were determined. (If you had tried to provide a z-value, the system would have rejected the input.)

QSAVE

Since you have drawn a couple of figures, you should now stop to save your work. As with any program, it's a good idea to save often to make sure you don't lose your work.

* Type qsave. Using qsave eliminates the need to type the file name; if you just type save, you have to remind the system of the file name. If you want to save the file under a different name, of course, just type save and then enter the new file name. Note: The pull-down menu commands are different here; save from the pull-down menu works as qsave from the keyboard does - saving the file under its current name. Use save as from the pull-down menu to save a file under a new name.

3DPOLY

Another way to make a polyline, but a polyline with variable z-coordinates, is to use the command 3dpoly. This command creates a 3D polyline (not to be confused with a standard polyline; there are differences we will talk about later).

* Type 3dpoly.

* For the first point, type 3.8,5,0.

* The system will prompt you for "Close/Undo/:" The brackets indicate the system's default expectation.

* So for the second point, simply type @2,0,1.

* For the third point, type @.75<180.

* For the fourth point, type @-2,0,0.

* Then type c to close the figure.

The last corner of the figure may show some extra marks, but that's from the point choosing process. If you type redraw, the extra marks will disappear.

You have now drawn Rect. C. Note that you have three rectangles, one consisting of lines, one of a single polyline, and one of a single 3d polyline. It is not possible automatically to convert the polyline into lines or a 3d polyline, nor is it possible to convert a 3d polyline into lines. It is possible, though, to convert lines into a polyine if and only if the lines all lie in the same horizontal plane.

At this point, you should hear about the difference between choosing an object and then saying what to do to it (noun-verb) and the reverse process, stating the action and then picking the object to act on (verb-noun). AutoCAD will permit you to do either. Generally speaking, it's probably easier to select the item and then name the action if you are only working on one item, but better to state the action first if you are working on many items at once. If you state the action first, you can keep adding (or removing) objects to act on until you are satisfied. That's more difficult to do if you name the objects first. You may, however, use either procedure with equal results.

Please note that, if you have chosen an object, it will be highlighted (with a broken line), and it will remain highlighted until you do something to it or type control-C twice (escape key with Release 13) to deselect all objects.

* Now let's move the last rectangle we drew so that the three rectangles form a letter F. As it is, the last rectangle looks a little too low; so we need to move it up. That is, we need to change the y-coordinates but not the x- or z-coordinates.

We must first know how far we are going to move it. We would like the rectangle to be in the middle of the vertical rectangle on the left. But where is the middle? To find out, you can query AutoCAD with the command distance ( or dist). You must be sure, however, to ask AutoCAD to supply distances between the points in the model; so AutoCAD must be told to seek points on the objects, not points in space. As you saw earlier, it is not possible to identify such object points precisely with the mouse alone.

DISTANCE

To use the distance command, you would type dist and then endpoint (end will also work, but, if you mistype dist, you may end your drawing session by accident when you type end, since AutoCAD will interpret that as the end command described below - but remember that the mouse probably lets you avoid typing altogether). Then you would select the endpoint of a line with the mouse, type endpoint again and select the other end of the line with the mouse. The distance between the two points would then be displayed by AutoCAD.

* In this case, we really want to know what the distance is from the middle of the side of Rect. A to the middle of the facing end of Rect. C. We can use midpoint or mid instead of endpoint to find out more simply than by starting with endpoints. Type dist, then midpoint, then select the right side of Rect. A, then type midpoint again, and select the left side of Rect. C. You should find that the middle of the side of Rect. A is 0.627 units from the middle of Rect. C. But that's not really the right distance for us to move Rect. C, because we want the middles to be in line horizontally but not to be in the same place. The distance reported includes the distance the two points are apart in all three axes - that is, if you look closely, you will see that the difference in x-coordinates is 0.05; the difference in y-coordinates is .375, and the difference in z-coordinates is 0.50. The three-dimensional distance between the points is 0.627, but we are only concerned with the y-coordinate difference. So, to align them for our purposes, we just want to move Rect. C up by 0.375.

MOVE

* To move Rect. C, select Rect.C by clicking on any part of it. The whole rectangle should be highlighted.

* Then type move and, when prompted for the "Base point or displacement:," you have two or three options. (That's what makes using AutoCAD either interesting or infuriating, depending on your point of view.)

* You know that the figure is to be moved .375 unit up (.375 unit in the y direction); so you could type 0,.375,0 and then, when prompted for "Second point of displacement:," just type to complete the command. You would have entered the displacement at the first prompt, and nothing at the second. That would tell the system to move the object nothing in the x direction, .375 unit in the y direction, and nothing in the z direction.

* Alternatively, you may select a base point at the first prompt (with coordinates from the keyboard or with the mouse or with endpoint and the mouse) and then, at the second prompt, indicate the new location of that point with the mouse, new points from the keyboard, or vectors (the @-style locations we used before). For instance, you could first select, as the base point, a corner of the figure, and then, when prompted for the new location of that point, type @0,.375,0. That would accomplish the same result.

COPY

To place another rectangle along the bottom and to make our F into an E, you can copy the horizontal one from the top (Rect. B). To copy it and put it in the correct place, you will first select the item to copy, then you will indicate which point on the item should be used to determine its position (the "base point"), and then you will define the location for that point (the "second point of displacement").

* Begin by selecting Rect. B, either by enclosing it in a window or by just clicking on each line making the rectangle. (Be sure not to include any of Rect. A or C, and that's not easy.) You will need to be sure you have each line of Rect. B, since it was drawn using the line command instead of the polyline command. If you select too much so that Rect. A has also been selected, then you must deselect - using Control-C or the escape key twice - and start again.

* Then type copy and, when prompted for "/ Multiple:," you should choose the lower left corner of Rect. B with the mouse; that's the point you will position accurately. (Be certain to type endpoint first. Note: if you had responded with m that would have indicated that you wanted to make multiple copies.)

* You will then be asked for the second point of displacement, and you want to place that new rectangle so that it fits the pattern - with its corner aligned with the bottom of Rect. A and the left side of Rect. B. Another way to look at that is to realize that the lower left corner of the new rectangle should have the x-value of the lower left corner of Rect. B and the y-value of the lower right corner of Rect. A.

* We can specify those coordinates in two steps, as follows: type .x, then endpoint, then pick the appropriate corner of Rect. B. (The period before the x in that sequence indicates that you are supplying only the x-coordinate for the new location.) The system will indicate that you still need a y-coordinate and a z-coordinate.

* Type .y, then endpoint, and then pick the appropriate corner of Rect A. The system will then indicate that you still need a z-coordinate. Type 0.

The new figure should now be in the correct place, and you have a Rect. D. (If you had typed .xy or .xz, the system would have used those, i.e., the x- and y-coordinates or the x- and z-coordinates of the point then selected, prompted you for the missing third coordinate, and then placed your object.)

TEXT

* The rectangles should be labeled on screen so that we can refer to them more easily. The command for this is text and you will have to choose the location for the text with your mouse or with coordinates typed at the keyboard.

* Type text.

* Pick a point in the middle of rectangle B (the horizontal one at the top) with the mouse or type the coordinates.

* You will then be prompted for height; you should respond with the height of the text - in drawing units. We recommend .3.

* The next prompt asks for rotation angle; since we have specified 0 degrees as north, the system will use 90 degrees as the default. Accept the default.

* Type the text, Rect. B.

* You will probably find that the text is too far to the right. Click on it and note the blue square at the left end (the handle, in AutoCAD parlance). Instead of typing move, you can just click on the handle and drag the text to the left so that it falls entirely inside the rectangle.

* Label the other rectangles in the same fashion.

When you label Rect. A, you will want to rotate the text so that the label fits. What should the rotation angle be?

Type qsave to save your work.

EDITING OBJECTS

* The lowest horizontal rectangle should be Rect. D, but it seems too short. It would look better as the leg of an E if it were about .4 unit longer. Let's change it using one of AutoCAD's easiest editing features. But we can't quite reach all the edges of the rectangle currently; so type zoom.8x (to make the new image only 80% the size of the current image). Now select the lines that make the top, right, and bottom of Rect. D (just click on the lines with the mouse). You should see the lines highlighted and a blue box in each corner. AutoCAD calls the blue boxes handles; you can move them easily. Pick the box in the upper right corner; it will turn solid red. Now you could just drag to a new point, but you know that using the mouse alone for location can be dangerous. So you can also type @.4,0,0 to move the point. Do that, and then do the same for the bottom right point. (What would have happened if you had only selected the line on the right of the rectangle? The move would only have affected that line, and the rectangle would have been pulled apart.)

MSLIDE

* Then save a screen image as a file for retrieval, by typing mslide and giving the slide the same name you have used for your model file plus the character "1." (For example, if your model file is named "jsmith," the slide file will be named "jsmith1.") AutoCAD automatically appends .sld to the file name. (This command allows any screen image to be saved - as an image only - and then retrieved for viewing. But it's only an image. Other than showing you how to make a screen image, this is built into the tutorial in case an instructor wants to be able to check your progress easily by seeing what the screen looked like at the end of the session. If you are using the tutorial alone, you need not save additional screen images.)

END

* Now you need to save the file and quit. Type end. (If you just say quit, your work since the last save will be lost, but AutoCAD will prompt you to be sure that's what you intend.)

End of Session One



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source : http://www.digitalcad.com/Htm/tutorials/CSA_beginners_autocad.htm

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