LESSON 1-1

X-Y CO-ORDINATE SYSTEM, INPUTTING POINTS THE AUTOCAD SCREEN BASIC AUTOCAD TERMINOLOGY

LESSON 1-2

ASSIGNMENT 1 - INTRO TO DRAWING / MODIFYING COMMANDS

LESSON 1-3

ASSIGNMENT 2 - MORE MODIFYING COMMANDS

LESSON 1-4

ASSIGNMENT 3 - ACCURATE INPUT

LESSON 1-5

SELECTION SETS

LESSON 1-6

ASSIGNMENT 4 - MODIFYING COMMANDS

LESSON 1-7

ASSIGNMENT 5 - MODIFYING COMMANDS

LESSON 1-8

ASSIGNMENT 6 - LAYERS / DIMENSIONING / TEXT

LESSON 1-9

DIRECT DISTANCE ENTRY AND OBJECT TRACKING

LESSON 1-10

CHANGING THE PROPERTIES OF OBJECTS

Notes about these lessons:

Most regular text is in burgundy on these pages. Anything you see on AutoCAD's command line is in blue Courier font. Important terms are usually highlighted in red and will also have hyper links attached. Whenever you see a icon, click on it for more information.

Commands covered in this Lesson:

Basic Drawing Skills

The previous lesson dealt with drawing commands. This lesson will introduce the common modifying commands. In AutoCAD, you will use modifying commands more often than drawing commands. Now that you know that basics, here's some more commands to add to your collection.

Command	Keystroke	Icon	Menu	Result
Rectangle	RECTANGLE / REC		Draw > Rectangle	Draws a rectangle after you enter one corner and then the second.
Multi Lines	MLINE / ML	No Icon	Draw > Multiline	Draw parallel lines based on the parameters you define.
Trim	TRIM / TR		Modify > Trim	Trims objects to a selected cutting edge.
Extend	EXTEND / EX		Modify > Extend	Extends objects to a selected boundary edge.
Offset	OFFSET / O		Modify > Offset	Offsets an object (parallel) by a set distance.
Object Snaps	OSNAP / OS / F3	CLICK	Tools > Object Snap Settings	Brings up the OSNAP dialog box.

Assignment #2 - Modifying Commands

The purpose of this assignment is to use the commands learned in the previous lesson and learn some new ones.

Duplicate the drawing called Assign_2.
Click HERE to download the DWG file.

Once again, do not worry about title blocks, text or dimensions, draw only what is in yellow.

Start AutoCAD and begin the the drawing by opening up the template file like you did in Lesson 1-2.

Draw a LINE from 1,2 to 3,2 to 3,4 to 1,4 (*Remember to watch the command line as you do this.) For the last line, you can either type in 1,2 or C to close the line back to the first point you entered. These are absolute co-ordinates. Make sure you understand what the points your just entered represent.

Draw the next square using the RECTANGLE command. A rectangle is created by specifying 2 points to represent the opposite corners. Enter the first point as 4.5,2 and then make the opposite corner 2 inches over and 2 inches up @2,2 using relative co-ordinates. This is much faster and also makes the square one object and not 4 separate lines.

ERASE the rectangle. You will see that all of it is gone with one pick. Redraw it and continue.

Draw the third box using the MULTILINE command. This box is 1-1/2" square. The following steps are what you will see on the command line. Before drawing the lines, you have to set the SCALE (distance between the lines) by typing 'S'. Then set the JUSTIFICATION (offset origin) by typing 'J'.

Command: ml <enter>
MLINE
Current settings: Justification = Top, Scale = 1.00, Style = STANDARD
Specify start point or [Justification/Scale/STyle]: s <enter>
Enter mline scale <1.00>: .15
Current settings: Justification = Top, Scale = 0.15, Style = STANDARD
Specify start point or [Justification/Scale/STyle]: 8,2 <enter>
Specify next point: @1.5,0 <enter>
Specify next point or [Undo]: @0,1.5 <enter>
Specify next point or [Close/Undo]: @-1.5,0 <enter>
Specify next point or [Close/Undo]: @0,-1.5 <enter>
Specify next point or [Close/Undo]: <enter>

To review what you just did, you started the command, then set the scale (distance between the lines) to .15 units. Then you just drew the rectangle using relative co-ordinates.

Erase the multiline rectangle you just drew.

Draw it again as shown below and note the subtle difference from the first one you drew.

Command: ML <enter>
MLINE
Current settings: Justification = Top, Scale = 1.00, Style = STANDARD
Specify start point or [Justification/Scale/STyle]: s <enter>
Enter mline scale <1.00>: .15
Current settings: Justification = Top, Scale = 0.15, Style = STANDARD
Specify start point or [Justification/Scale/STyle]: 8,2 <enter>
Specify next point: @1.5,0 <enter>
Specify next point or [Undo]: @0,1.5 <enter>
Specify next point or [Close/Undo]: @-1.5,0 <enter>
Specify next point or [Close/Undo]: C <enter>

The difference is that instead of drawing to the last point, you used the C (close) option to complete the rectangle. The difference is shown in the drawing below.

This is an example of why you have to look at the command line as you work. As soon as you start the command, you have choices available. Whenever you see this come up, if you want to change anything, you just type the CAPITOL letter of the option. For example, if you want to undo the last point, you would type u at this point. For this assignment you only changed the scale. After you have completed the assignment, try different settings for this command. Use your AutoCAD help option to see what these options control.

Multilines are useful for when you need parallel lines and want to edit them together, although they cannot be trimmed (you have to explode them first).

Draw a line from 2,5 to 2,6.5 Draw another line from 1,6 to 3,6 You should now have two perpendicular lines. What you want to do is trim off the top of the vertical line and create a T.

Start the TRIM command. It will first ask for a cutting edge. Select the horizontal line and press <ENTER>. It will now ask for the object to be trimmed. Select the vertical line anywhere above the horizontal (cutting) line and press <ENTER> to finish the command.

This is what you saw on the command line:

Command: TR <enter> TRIM
Current settings: Projection=UCS, Edge=None
Select cutting edges ...
Select objects: <Select the Horizontal line>1 found
Select objects: <enter>
Select object to trim or shift-select to extend or [Project/Edge/Undo]: <Select the vertical line>
Select object to trim or shift-select to extend or [Project/Edge/Undo]: <enter>

Once again, it is important to keep your eye on the command line as it will guide through most commands.

Draw a LINE from 4,6.5 to 6,6.5 Draw another line from 5,5 to 5,6 What you want to do now is extend the vertical line up to the meet horizontal line. Start the EXTEND command. AutoCAD asks for a boundary edge; select the horizontal line press <ENTER>. It then asks for an object to extend; select somewhere in the top half of the vertical line. Press <ENTER> to end the command. Your command line history should match what is printed below.

Command: EX <enter> EXTEND
Current settings: Projection=UCS, Edge=None
Select boundary edges ...
Select objects: <Select the horizontal line> 1 found
Select objects: <enter>
Select object to extend or shift-select to trim or [Project/Edge/Undo]: <Select the top half of the vertical line>
Select object to extend or shift-select to trim or [Project/Edge/Undo]: <enter>

Draw a CIRCLE with a center point of 7.5,5.5 with a radius of .5 Now you will use to offset command to make another circle 1/4" larger. Start the OFFSET command (watch the command line) and enter .125 as the offset distance. Now select the circle and pick anywhere outside the circle. Press <ENTER> to end the command.

Object Snaps

Suppose you want to draw a line from the center of the circle to the middle of the vertical line you extended earlier. AutoCAD has a feature that makes this very easy. These are the Object Snaps (or Osnaps "Oh-Snaps"). Type OS <ENTER> . You will see this dialog box appear.

You may also see a toolbar with these Osnaps as shown below.

ICON	SETTING		ICON	SETTING
	Endpoint			Perpendicular
	Midpoint			Tangent
	Center			Nearest
	Node			Apparent Intersection
	Quadrant			Parallel
	Intersection			None
	Extension			Osnap Setting
	Insertion Point			Temporary Tracking Point
				Snap From

You may select whichever points you want to 'snap' on an object. Here is a list of your options. Followed by the command entry to invoke the needed Osnap.

Endpoint - snaps to either the beginning or the end of an object such as a line - END

Midpoint - snaps to the exact middle of a line or an arc - MID

Center - snaps to the center-point of a circle or arc - CEN

Node - snaps to 'nodes' (not covered in this course) - NOD

Quadrant - snaps to any of the four quadrants of a circle - QUA

Intersection - snaps to the point where two object cross - INT

Extension - Snaps to the phantom extension of an arc or line - EXT

Insertion - snaps to the insertion point of an object (such as a block or text) - INS

Perpendicular - will snap so that the result is perpendicular to line selected - PER

Tangent - snaps to create a line tangent to a circle or arc - TAN

Nearest - will find the closest point an object and snap to that point - NEA

Parallel -Snaps parallel to a specified line - PAR

None - temporarily turns off all Osnaps. (Pressing your F3 Key is quicker) - NON

Osnap settings - opens the Osnap dialog box.

Temporary Tracking - Creates a temporary tracking point (see Object Tracking).

From - Allows you to select a point, then denote a new location 'from' that point using relative co-ordinates. This can save you the time of drawing (and erasing) construction lines.

Note: Beside each checkbox is a symbol. That symbol will show up on the screen when you have found a valid snap point. (An endpoint will show a small square). If you select the "Options" button, you can change the aperture size and the color of the Osnaps. Depending upon the background you are drawing on, this may be needed.

1. Check off the boxes as shown in the dialog box above (Object Snaps On, Endpoint, Midpoint, Center) and press OK.

2. Begin the LINE command. Move your cursor around the screen and you'll see that as you get close to an object, it will 'snap' to one of the points that you had checked off in the dialog box. Place your cursor on the circle until you see a small purple circle appear at its center. Left-click to make this the start point of the line. Move the cursor towards the middle of the vertical line until you see a small triangle appear. (Remember this is the symbol for 'midpoint'). When you see it left-click to accept this as your endpoint. Press <ENTER> to end the line command.

3. Save your drawing.

4. Print your drawing with the same settings as in Assignment #1.

TIP: Before you select the Osnap you want, you can press the TAB key on your keyboard to cycle through the available Osnaps in the area of your cursor.

When you have finished the assignment, continue practicing with the commands you have just mastered!