Cad me2155-lab-manual

Ex.no.:

INTRODUCTION TO AUTOCAD

Date:

DRAWING AND MODIFYING OBJECTS
Autocad is a drafting/modeling software used all over the world by almost all
manufacturing companies. It is a variable software which can be used in all
engineering divisions. It is a drafting version popularly known to everyone associated
with mechanical engineering. The Autocad drawing enables the designer to
communicate his ideas to the outside of department easily.
Conversion of Autocad files to other software is also using drawing exchange

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formula. In the lesson, commands and procedures for drawing and modifying the

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objects are explored.

START AND SAVE A DRAWING

When you start a drawing, you specify the type of units and other settings you
can also choose how to save your files, including saving back up files.

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The settings you select, English a metric determines default values used for

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and hatch pattern life.

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many system variables of controlling text dimensions, grid, snap and default line type

ENGLISH - Creates a new drawing based on Imperial Measurement System.

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The drawing is based on cad.dwt template.

METRIC
Creates a new drawing based on metric measurement. The drawing is based on
ocadiso.dwt template. Save drawing files for later use.

CONTROL THE VIEWS
You can magnify the details in your drawing for a closer view or shift the view
to a different part of the drawing. If you can save the view by name, you can restore
them later.

UNITS
Every object is measured in units. In AutoCAD we can determine the value of
the units before we draw.

LIMITS
The drawing limits are two-dimensional points in the world coordinate that
represent a lower-left limit and an upper right limit. You cannot impose limits on the
Z direction.

ABSOLUTE COORDINATE SYSTEM

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In Absolute Coordinate System, the dimensions X and Y of a point is specified

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with reference to the origin (0,0).

RELATIVE COORDINATE SYSTEM

In Relative Coordinate System, the dimensions X and Y of a point are
specified with respect to the last entered point (ie) the last enter point is taken as

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origin.

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POLAR COORDINATE SYSTEM

In Polar Coordinate System, the dimensions of a point are specified by using a

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distance and angle with reference to the previous point. Angles are measured in anticlockwise direction, taking 0 degrees towards right.
LINE
Line command allows you to create a line where the end points are specified
by two dimensional or three dimensional coordinates.

POLYLINE
PLINE command allows you to draw line and arc segments, but from start to
end, it is treated as a sing object. With PLINE command, you can draw objects even
with line width.

ARC
The ARC command allows you to create an arc segment. There are different
methods of creating an arc. The different methods of creating an arc are:
1)3 Points
2)Centre, Start, Radius
3)Start, Centre, End
4)Start, Centre, Angle
5)Start, Centre, Length
6)Start, End, Angle
7)Start, End, Direction

CIRCLE

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8)Start, End, Radius

The CIRCLE command allows you to create a circle. There are four different
methods for drawing circles. They are:
Centre, Radius/Centre, Diameter

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3 Points (3P), 2 Points (2P)

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Tangent, Tangent, Radius (ttr)

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POLYGON

Polygon command creates a regular polygon. You must specify the number of

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sides of the polygon and whether it is Inscribed or Circumscribed polygon. Now,
specify the centre and radius of the polygon circle.

OSNAP
Osnaps allow you to snap onto a specific object location when you are picking
a point. For example, using Osnaps you can accurately pick the end point of a line or
the center of a circle.

ERASE
This command is used for deleting unwanted objects. You must select the
object to be erased.

COPY
The copy command is used for making copies of selected objects. The object
to be copied must be selected and the base point must be specified and the copy can
be dragged and placed at the required position.

MOVE
This command is used for moving selected objects. The object to be moved
must be selected and its base point must be specified then we can drag it to the

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required location.

ROTATE

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This command is used for rotating selected objects. To rotate an object, first
select it and specify a base point. Now enter an angle value or specify a second point
to rotate the object.

Entering a positive angle value rotates the objects counterclockwise or

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clockwise, depending on the Direction Contorl Control setting and Drawing Units

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dialog box. The plane of rotation and the direction of the zero angle depend on the

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MIRROR

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orientation of the user coordinate system.

The MIRROR command is used for creating mirror images of selected objects.
You must first select the object to be mirrored and then specify the axis along which
it is mirrored, to create an mirror image of the selected object.This is a very useful
command for drawing symmetrical objects about a particular axis.
OFFSET
Offset an object to create a new object whose shape parallels the shape of the
original object. Offsetting a circle or an arc creates a larger or smaller circle or arc,
depending on which side you specify for the offset.

POLAR ARRAY
This command creates an array of the selected object around a centre point.
You must specify the centre point of the array, the total number of items and the
angle to fill for creating a polar array.

RECTANGULAR ARRAY
This command creates an array of the selected objects defined by the number
of rows and columns and the offset between them.

EXTEND

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The EXTEND command elongates the selected objects to a specified

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boundary.

TRIM

The TRIM command trims off an object using cutting edges defined by other
objects. Here the user is required to select object(s) to define cutting edge(s) then

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select the object to be trimmed, the selected side of the object is removed based on

BREAK

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the side of selection of the object to be trimmed relative to the cutting edge.

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The BREAK commands is used to remove only parts of an object. You must
specify the first and second points between which the object must be deleted.

FILLET
FILLET rounds of the edges of two arcs, circles, elliptical arcs, lines,
polylines, rays, splines or xlines with an arc of a specified radius. Rounds along the
edges cannot be created with zero radius.

CHAMFER
CHAMFER command draws a line at the corner between two selected lines. If
the lines do not intersect, it extends the lines. If they intersect, the lines extending
beyond the chamfer line can be trimmed or left as it is, by the trim mode.

LENGTHEN
The LENGTHEN command is used to increase/decrease the length of
AutoCAD objects.

DIVIDE

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This command places evenly spaced point objects or blocks along the length or
perimeter of an object. You can select only one entity at a time to be divided. The

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entities that can be selected are: line, arc, circle, polyline and spline.

ZOOM ALL

This zoom to display the entire drawing in the current viewport. The display

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ZOOM WINDOW

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shows all the entities even if the drawing extends outside the drawing limits.

ZOOM WINDOW commands to display an area specified by two diagonally

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opposite corner points of a rectangle window.

ZOOM EXTENTS
This zoom to display the drawing extents. If the drawings are small in the
existing limits, then there is an enlarging effect on the screen. If the drawing occupy
the complete area of the limits, then there are many not be much difference between
ZOOM ALL and ZOOM EXTENTS.

DIMLINEAR
This command specifies the linear distance between two selected points.

DIMALIGNED
This command is used for specifying the linear distance (exact dimensional
value) between two points which are inclined at an angle.
DIMANGULAR
This command is used for obtaining the angle two selected points. The three
types are:
1)Arc Selection
2)Circle Selection
3)Line Selection

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4)Three Point Selection

DIMRADIUS

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This command gives the value of radius of the specified circle, arc or fillet. A
radial dimension consists of a radius dimension line with an arrowhead at the arc or

DIMCENTER

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circle end.

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This command marks the centre point of the selected arc or circle. The center

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LINETYPE

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mark cannot be updated, so set the required style before executing this command.

LINETYPE greatly improves the readability of technical drawings. You can
make important features stand out with bold line weights.

LAYER
Layer is an organizing tool. Layers are like one, where you can keep various
types of information. It’s always a good idea to keep notes and reference symbols
about each element of the drawing as well as drawing dimensions on a new layer.

DISTANCE
This command lists the distance between the selected points and also lists out
the angle in current plane and 3D angle from the current plane, based on the direction
of picking the two points. It also lists the projected lengths on the three axes called
the delta length.

TEXT
TEXT command creates text objects with specified height and orientation.
Text objects can be created with a variety of character patterns call style. This

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command allows you to type a single line or multiple lines of text.

MTEXT

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MTEXT creates paragraph that fit within a nonprinting text boundary. The
user specified text boundary determines the width of the paragraph and the
justification of the text within the paragraph. Each multiline text object is a single

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object, regardless of the number of lines it contains.

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HATCH

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Hatches are shaded pattern which generally represent cross-section of a
mechanical component. Using BHATCH command the required area, type of hatch,

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hatch angle and scale can be specified.

PROPERTIES
The PROPERTIES command displays the Properties palette. The Properties
palette is the main method for viewing and modifying the properties of AutoCAD
objects.

VPORTS
Viewports are areas that display different views of your model. As you work
on the Model tab, you can split the drawing area into one or more adjacent
rectangular views known as model space viewports. In large or complex drawings,

displaying different views reduces the time needed to zoom or pan in a single view.
Also, errors you might miss in one view may be apparent in the others.

EXTRUDE
Solids can be created by extruding selected objects. Use the EXTRUDE
command to create a solid or surface from a common profile of an object

REVOLVE
REVOLVE command can create a solid or surface by revolving open or
closed objects about an axis. The revolved objects define the profile of the solid or

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surface.

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PYRAMID

This command can create a solid pyramid. The number of sides for a
pyramid, from 3 to 32, can be defined. The axis endpoint defines the length and

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CREATE LAYOUTS

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orientation of the pyramid.

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A layout stimulates a sheet of paper and provides a predictable plotting setup
for a layout, you can create and position view post objects and you can add a title

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block or other objects geometry.

PLOT DRAWINGS
Once you have completed a drawing you can plot the drawing on paper or
create a file for use with another application. In either case, you select the plot
settings.

Ex.no.:

CREATION OF SIMPLE OBJECTS

Date:

Aim:
To create simple objects like polygon and general multi-line figures using
Auto CAD software.

Software Used:

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Auto CAD 2008

Commands Used:

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Limits, Zoom, Line, Arc, Circle, co-ordinate systems, Dimlinear

Procedure:

1) Limits are set for A4 standard drawing size. Margins are drawn using lines.

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2) Using Line command and appropriate co-ordinate system, the given figures

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are drawn and aligned

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3) The drawn figures are dimensioned using respective DIM command.
4) Title Block is drawn for the given dimension.

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5) Finished work sheet is saved and hard copy is taken.

Result:
The given simple figures like polygon and general multi-line figures are drawn
using Auto CAD software.

Ex.no.:

SPECIAL CURVES

Date:

Aim:
To create special curves like parabola, spiral, involute (square and Hexagon)
using Bspline or Cubic Spline using Auto CAD software.
Software Used:
Auto CAD 2008

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Commands Used:

Limits, Zoom, Line, Polygon, Arc, Circle, Offset, Copy, Move, Trim, Pline,

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Pedit, DIM
Procedure:

1) Limits are set for A4 standard drawing size. Margins and title block are
drawn using lines.

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2) From the given data, the Loci points of Parabola are found and joined using

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Pline and then fitted using Pedit command

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3) From the given data, the Loci points of square and hexagonal involutes are
found and joined using arc command.

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4) From the given data, the Loci points of Spiral are found using Concentric
circles or arc method, and joined using Pline and then fitted using Pedit
command.
5) Drawn curves are dimensioned appropriately.

Result:
The special curves like parabola, spiral, involute (square and Hexagon) using
Bspline or Cubic Spline are drawn using Auto CAD.

Ex.no.:

PROJECTION & SECTION OF SIMPLE SOLIDS

Date:

Aim:
To draw front and top view of given simple solids (prisms and pyramids) using
Auto CAD software.

Software Used:

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Auto CAD 2008

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Commands Used:

Limits, Zoom, Line, Polygon, Arc, Circle, Offset, Copy, Move, Trim, Layer,
DIM, Mtext.

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Procedure:

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drawn using lines.

2) Using Line, Circle, Polygon commands, front and top view of given simple

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solids are drawn

3) Layer is defined (for line type, line weight and colour) sepeartely for
visible, hidden, axis and dimension lines and applied.
4) Sectional views are drawn and section is created using Hatch command.
5) Drawn solids are named and dimensioned accordingly.
Result:
The front and top views of the given simple solids (prisms and pyramids) are
drawn using Auto CAD.

Ex.no.:

ORTHOGRAPHIC VIEWS OF SOLIDS

Date:

Aim:
To draw the orthographic views from the given pictorial views using Auto
CAD software.

Software Used:

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Auto CAD 2008

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Commands Used:

DIM.

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Procedure:

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drawn using lines.

2) Using appropriate commands, front, top and Left side view of given solids

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are drawn.

3) Layer is defined (for line type, line weight and colour) sepeartely for
visible, hidden, axis and dimension lines and applied.
4) Drawn solids are dimensioned accordingly.

Result:
The orthographic views of the given solids are drawn using Auto CAD.

Ex.no.:

ISOMETRIC VIEWS OF OBJECTS

Date:
Aim:
To draw the isometric view of given simple solids and objects using Auto
CAD software.
Software Used:
Auto CAD 2008
Commands Used:

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DIM, Mtext

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Procedure:

drawn using lines.

solids are drawn.

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2) Using Line, Circle, Polygon commands, front and top view of given simple

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3) Snap is changed from Rectangular to Isometric to help draw the Isometric

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view. F5 key is used to invoke/toggle between the different Isoplanes
(Left, Top, Right) accordingly.

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4) Given objects are taken and drawn in Isometric.
1) Drawn solids are named and dimensioned accordingly.

Result:
The Isometric view of the given simple solids and objects are drawn using
Auto CAD.

Ex.no.:

PLAN OF RESIDENTIAL BUILDING

Date:

Aim:
To create the plan of given residential building using Auto CAD software.

Software Used:

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Auto CAD 2008

Commands Used:

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Limits, Zoom, Line, Offset, Copy, Move, Multiline.

Procedure:

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drawn using lines.

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2) Using Mulitline command, plan of the given residential building is drawn.
3) The plan is dimensioned and the rooms are named accordingly.

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Result:
The plan of the given residential building is drawn using Auto CAD.

Ex.no.:

SIMPLE TRUSSES

Date:

Aim:
To draw simple trusses using Auto CAD software.

Software Used:

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Auto CAD 2008

Commands Used:

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Limits, Zoom, Line, Offset, Copy, Move, Trim, Extend, DIM.

Procedure:

drawn using lines.

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2) Using appropriate commands, simple trusses with combinations of King

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and Queen posts are drawn.

3) Drawn figure is dimensioned accordingly.

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Result:
Simple trusses are drawn using Auto CAD.

Ex.no.:

3D MODELING OF SIMPLE SOLIDS

Date:

Aim:
To create 3-D Models of given simple solids and obtain 2-D multi view
drawings Auto CAD software.

Software Used:

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Auto CAD 2008

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Commands Used:

Zoom, Line, Polygon, Arc, Circle, DIM, Extrude, Revolve, Pyramid.

Procedure:

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1) Auto CAD 3-D template is opened for creating 3-D models.

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command.

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2) Prisms are created using Extrude command and pyramids by Pyramid

3) Objects of revolution like cylinder and cone are created using Revolve

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command.


Result:
3-D Models of given simple solids are created using Auto CAD.

Ex.no.:

2D MULTIPLE VIEWS FROM 3D MODEL

Date:

Aim:
To create a Title Block with necessary text and projection symbol using Auto
CAD software

Software Used:

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Auto CAD 2008

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Commands Used:

Limits, Zoom, Line, Circle, Layout, Text, Mtext

Procedure:

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1) Limits are set for A4 standard drawing size. are drawn.

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2) Given Solid is modeled using Extrude command.

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3) Layout is created with four viewports for Front, Top, Left Side and
Isometric views.

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4) Dimensioning is done in the appropriate views.

Result:
2D multiple views were obtained for the given solid using Auto CAD
software.

Cad me2155-lab-manual

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