ىلولاا ةلحرملا · 1. SNAP (F9 or status bar) Snap has two modes in AutoCAD: 1- Grid...
Transcript of ىلولاا ةلحرملا · 1. SNAP (F9 or status bar) Snap has two modes in AutoCAD: 1- Grid...
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Department of Computer Engineering& Information Technology
قسم هندسه الحاسبات و تكنلوجيا المعلومات
المرحلة االولى
Lecture (1)
Drawing by AutoCAD
Issued by Assistant Lecturer
Ameer Mosa Thoeny
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Drawing by AutoCAD
The CAD data base:
A CAD (Computer Aided Design) file, which is the
electronically stored version of the drawing, keeps data in
binary digital form. These digits describe coordinate values
for all of the end points, center points, vertices, etc. for all
the objects composing the drawing, along with another
code that describes the kinds of objects (line, circle, arc,
ellipse, etc.).
Graphics Area:
The large central area of the screen is the Graphics
area. It displays the lines, circles, and other objects you
draw that will make up the drawing.
The cursor is the intersection of the crosshairs (vertical and
horizontal lines that follow the mouse or puck movements).
The default size of the graphics area for English settings is
12 units (x or horizontal) by 9 units (for vertical).this
usable drawing area (12*9) is called the drawing limits and
can be changed to any size to fit the application. As you
move the cursor, you will notice the numbers in the
coordinate display change.
Command Line:
The command line consist of the three text lines at the
bottom of the screen (by default) and is the most important
area other than the drawing itself. Any command that is
entered or any prompt that Auto CAD issues appear here.
The command line is always visible and gives the current
state of drawing activity.
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Tool bars:
AutoCAD provides a variety of tool bars. Each toolbar
contains a number of icon buttons (tools) that can be picked
to invoke commands for drawing or editing objects (lines,
arcs, circle, etc.) or for managing files and other functions.
*The standard toolbar is the row of icons nears the top of
the screen. The standard toolbar contains many standard
icons used in other windows applications ( like New, Open,
Save, Print, Cut, Paste, etc.) and other icons for AutoCAD
specific functions (like Zoom and Pan).
*The object properties toolbar located beneath the standard
toolbar is used for managing properties of objects, such as
layers and types.
*The draw and modify toolbar also appear (by default)
when you first use AutoCAD. The draw and modify
toolbars (side) and the standard and object properties
toolbar (top) are docked.
*The status bar is a set of informative words or symbols
that gives the status of the drawing aids. The status bar
appears at the very bottom of the screen. The following
drawing aids can be toggled on or off by single clicking
(pressing the left mouse button once) on the desired word
or by using function keys.
*The following drawing aids are listed below
SNAP, GRID, ORTHO, POLAR, OSNAP, and
MODEL.
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Drawing Aids:
1. SNAP (F9 or status bar)
Snap has two modes in AutoCAD:
1- Grid SNAP.
2- Polar SNAP.
*Grid snap is a function that forces the cursor to “snap” to
regular interval (0.5 units is the default English setting)
which aids in creating geometry accurate to interval lengths.
You can use the snap command or the drafting setting
dialog box to specify any value for the grid snap increment.
*Polar snap forces the curser to snap to regular interval
along angular lines.
Since you can have only one snap mode on at a time (grid
snap or polar snap), you can select which of two is on by
right-clicking on the word, SNAP on the Status bar.
2. Grid (F7 or status bar)
A drawing aid called Grid can be used to give a visual
reference of units of length. The GRID default value
for English settings is 0.5 units. The GRID command
or drawing Aids dialog box allows you to change the
interval to any value.
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3. ORTHO If ORTHO is on, lines are forced to an orthogonal alignment
(horizontal or vertical). ORTHO can be turned only on or off.
4. Object SNAP MODES:
AutoCAD provides the following object snap modes.
1) Center
This OSNAP option finds the center of a circle, Arc, or
Dount.
2) End point
The End point option snap to the end point of a line, pline,
spline, or Arc.
3) Intersection
Using this option causes AutoCAD to calculate and snap to
the intersection of any two objects.
4) Mid point
The midpoint option snaps to the point of a line or arc that
half way between the end points.
5) Insert
6) Perpendicular
7) Nearest
8) Node
9) Tangent
This option calculates and snaps to a tangent point of an Arc
or circle.
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SETUP COMMANDS:
1-units command:
The units command allows you to specify the type and
precision of linear and angular units as well as the direction
and orientation of angles to be used in the drawing. There
are five types of units:
1. Scientific.
2. Decimal.
3. Engineering.
4. Architectural.
5. Fractional.
• There are two ways to execute it:
A. Menu bar ….> Format ….> Units.
B. Command line: Units
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2-LIMITS Command:
The limits command allows you to set the size of the
drawing area by specifying the lower-left and upper-right
corners in x,y coordinate values. Limits also define the
display area for GRID as well as the minimum area
displayed when a Zoom All is used.
• There are many ways to execute it:
A. Menu bar ….. > Format ……> Drawing limits.
B. Command line: limits
Specify lower left corner or [ON/OFF] <0.000, 0.000>:x,y
Specify upper right corner<12.0000, 9.0000>:x,y
3-Zoom Command:
The ZOOM command enables you to zoom in and out of your drawing, like
the zoom lens of camera. When you zoom in, everything is magnified so that
you can see it more easily, but you see less of the entire drawing. When you
zoom out, objects look smaller, but you can see more of the drawing. The
ZOOM command has several options that make it easy to see just what you
need at an appropriate size.
Note: Zooming does not affect the actual size of objects, just as zooming
with a camera lens does not affect the size of the scene you‟re viewing.
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• There are many ways to execute it:
A. Menu bar ….. > view ……> zoom.
B. Command line: zoom
Specify corner of window, enter a scale factor (nX or nXP), or [All/Center/Dynamic/Extents/Previous/Scale/Window] <Real time>: 2x
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Exercises:
Q1: Create a new drawing with the following settings:
1) You will use decimal units on your drawings.
2) Set up for a sheet of 300,220.
3) Set the values of grid and snap to 20.
4) Save the project as (shapes-dwg).
Q2: Start a new drawing set it up as follows:
1) Units: architectural.
2) Lower left limits:0,0.
3) Upper right limits:17:11.
4) Grid:1/2.
5) Snap:1/4.
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Department of Computer Engineering& Information Technology
قسم هندسه الحاسبات و تكنلوجيا المعلومات
المرحلة االولى
Lecture (2)
Layer
Issued by Assistant Lecturer
Ameer Mosa Thoeny
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Organizing Drawings with Layers, Colors, Linetypes, and Lineweights
Until now, we have drawn everything in black or white.
Drawing everything in one color is not a very good way to draw —
besides, it‟s boring! If everything is the same color and same line-
types, it‟s hard to distinguish the various elements of a drawing.
So with complex drawing we need to use various properties like
multicolor or multi linetype such as (continues or dashed lines) or
multi linewight such as (0.5, 0.9 or 1.3 mm) to help to organize our
drawings, making them easier to understand...
Most often, we assign color, linetype, and lineweight to a layer.
A Layer: is simply an organizational tool that lets you organize
the display of objects in our drawing.
Every object must have a layer, and every layer must have a color,
a linetype, and a lineweight.
We define layers to meet our drawing needs. Layers, colors,
linetypes, and lineweights are called object properties.
Layers give us many ways to organize your drawing. For example, we can:
✦ Assign different colors, linetypes, and lineweights to layers.
✦ Control the visibility of layers. Making a layer invisible lets us focus on
just the objects that we need to draw or edit.
✦ Control which objects are plotted.
✦ Lock a layer so that objects on that layer cannot be edited.
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Creating new layers
To create a new layer, choose Layer Properties Manager because it
is the best way to gain complete layer control. The layer properties
manager is invoked by using:
1. The icon button in properties toolbar.
2. Selecting layer from the format pull down or screen menu.
3. Typing the layer command.
New layers can be created by selecting the new button near the
upper right corner of the dialog box.
The command line format of layer shows all of the available
options.
Command: layer
Current layer: „0‟
[set /new/on/off/color/lweight/ltype/freez/lock]
The Layer Properties Manager dialog box opens, as shown:
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Columns in the Layer Properties Manager
Using layers We must know the meaning of each property to use it in effective
way, which is the same in properties toolbar or layer command
options, so we will explain it as shown below:
OR
Command: layer
Current layer: „0‟
[set /new/on/off/color/lweight/ltype/freez/lock]
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Current or Set: To set a layer as the current layer is to make it the active
drawing layer. Any objects created with draw command are
created on the current layer.
You can edit objects on any layer, but draw only on the current
layer.
Any layer can be can be mode current, but only one layer at a
time can be current.
To set the current layer with the layer properties manager, select
the desired layer from the list and then select the current tile.
ON,OFF: If a layer is on, it is visible. Object on visible layer can be edited
or plotted. Layer that are off are not visible. Objects on layers
that are off will not plot and cannot be edited. It is not advisable
to turn the current layer off.
Freeze: Freeze is amore protected state than off. Like being off, a frozen
layers not visible, nor can it is objects be edited or plotted.
Lock ,Unlock: Layer that are locked are protected from being edited but are
still visible and can be plotted.
Locking a layer prevents it is objects from being changed even
though they are visible. Layer can be locked and off.
Color: Selecting one of the small color boxes in the list area of the
layer properties manager causes the select color dialog box top
up. The desired color then can be selected.
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Line type: To set line type, select the line type (word such as continuous or
hidden) in the layer list, which in turn invokes the select line
type dialog box. Select the desired line type from the list.
Line weight: The line weight for a layer can be set by selecting the line
weight (word such as default or 0.20mm, 0.50mm, 0.010 “or
0.020”, etc.) in the layer list.
Exercise:
A. Begin a new a drawing. Set limits to 11*8.5, then zoom all.
Use the line type manager to list the loaded line types. Are
any line types already loaded? Pick the load button.
B. Use the layer properties manager to create 3 new layers
named OBJ, HID, and CEN. Assign the following colors, line
types, and line weights to the layers by clicking on the color,
line type, and line weight columns.
OBJ RED Continuous Default
HID Yellow Hidden Default
CEN Green Center Default
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Department of Computer Engineering& Information Technology
قسم هندسه الحاسبات و تكنلوجيا المعلومات
المرحلة االولى
Lecture (3) Coordinates entry methods, line and display coordinate
Issued by Assistant Lecturer
Ameer Mosa Thoeny
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The four coordinates entry methods:
All drawing commands prompt you to specify points
or locations, in the drawing. For example, the line
command prompts you to give the “specify first point” and
“specify next point” excepting you to specify locations for
the first and the second end points of the line. After you
specify these points, AutoCAD stores the coordinate values
to define the line. A two-dimensional line in AutoCAD is
defined and stored in the default base as two sets of X,Y
and Z values (with Z values of 0), one for each point.
There are four ways to specify coordinate:
1. Interactive method.
2. Absolute coordinates.
3. Relative rectangular coordinates.
4. Relative polar coordinates.
*Interactive method:
Use the cursor to select points on the screen. (Pick)
*Absolute method:
Absolute coordinates are used when AutoCAD
prompts for a point and you know the exact coordinates of
the desired location. You simply key in the coordinate
values at the key board (X and Y values are separated by a
comma).
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*Relative rectangular method:
Relative rectangular coordinates are similar to
absolute values except the X and Y distances are given in
relation to the last point, instead of being relative to the
origin.
AutoCAD interprets the @ symbol as the “last point”. Use
this type of coordinate entry when you do not know the
exact absolute values, but you know the X and Y distances
from the last specified point.
*Relative polar Rectangular:
Relative polar rectangular entry is often used when
you want to draw a line or specify a point that is at an exact
angle with respect to the last point. Interactive coordinate
entry is not accurate enough to draw diagonal lines to a
specified angle AutoCAD interprets the @ symbol as last
point and the <symbol as an angular designator for the
following value. So@ 2<45 “means from the last point, 2
units at an angle of 45 degrees”.
Drawing Commands
1. Line:
This is the fundamental drawing command. The line
command creates straight line segments; each segment
is an object. One or several line segments can be
drawn with the line command.
Command: Line
Specify first point: Pick
Specify next point: Pick
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Specify next point: Pick
Specify next point: Press enter to finish command.
Command:
Example:
1) Draw a horizontal line of 2 units length starting at
point 2,3 using absolute coordinates.
Command : L
Specify first point: 2,3
Specify next point: 4,3
2) Draw a horizontal line of 2 units length starting at
point 2,4 using relative coordinates.
Command: L
Specify first point: 2,4
Specify next point: @2,0
3) Draw a horizontal line of 2 units length starting at
point 2,5 using relative polar coordinates.
Command: L
Specify first point: 2,5
Specify next point: @2<0
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Displaying Coordinates As you work, you can refer to the coordinate display on
the status bar. This display helps you know where your cursor
and objects are when you draw and is also helpful when editing,
by informing you how far and in what direction you are
moving or copying objects.
AutoCAD and AutoCAD LT have three coordinate display
modes:
✦ Dynamic absolute coordinates (absolute): Absolute
coordinates that change as you move the mouse, as shown
bellow.
: Dynamic absolute coordinates.
✦ Static absolute coordinates (off): Absolute coordinates that
change only when you specify a point, as shown bellow. The
coordinate display is dimmed.
: Static absolute coordinates.
✦ Dynamic polar coordinates (relative): Polar coordinates
that change continuously as you move the mouse, as shown in
Figure 4-17. They appear after you‟ve already specified a point
and are ready to specify a new point, as when you‟re in the
process of drawing a line.
: Dynamic polar coordinates.
You can change the coordinate display in three ways:
✦ Press the F6 key.
✦ Click the coordinates area on the status bar.
✦ Press Ctrl+D.
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Exercise:
Draw the shapes below using line command.
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Department of Computer Engineering& Information Technology
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Lecture (4)
Drawing command Circle
Issued by Assistant Lecturer
Ameer Mosa Thoeny
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Circle:
The circle command creates one object. Depending on
the option selected, you can provide two or three points to
define a circle. As with all commands, the command line
prompt displays the possible options:
Command: circle
Specify center point for circle or [3p/2p/Ttr]: pick or
coordinates (x,y)
As with most commands, the default and other options are
displayed on the command line. The default option always
appears first. The other options can be invoked by typing
the upper case letter(s) that appear in brackets [].
The options, or methods, for drawing circles are listed
below:
1.Center, Radius:
Specify a center point, then a radius. the radius or
(Diameter) can be specified by entering values or by
indicating a length interactively (pick two points to
specify a length). As always, points can be specified
by picking or entering coordinates.
2. Center, Diameter:
Specify the center point, the diameter
Command:C
Specify center point for circle [3p/2p/Ttr]: 50,50
Specify radius or [Diameter]:D
Specify diameter of circle:20
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3. 2point:
The two points specify the location and diameter. The
tangent OSNAPS can be used when selecting points
with the 2point options.
4. 3points:
The circle passes through all three points specified.
5. Tangent, Tangent, Radius:
Specify two objects for the circle to be tangent to, then
specify the radius. The HR method is extremely
efficient and productive.
Example: Draw this shape using Line, Circle command.
Command: Line
Specify first point:20,20
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Specify next point:23,20
Specify next point:23,25
Specify next point:20,25
Specify next point:20,20
Command:C
Specify center for circle or radius:20,25
Specify radius for circle:0.5
Command:C
Specify center for circle or radius:23,25
Specify radius for circle:0.25
Exercise:
1)Draw this shape using the following setup:
Layers color line type
Box White continuous
Circle yellow dashed
Button Red hidden
Center Green dashed
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2) Create the shape below using the suitable commands.
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