computer drafting lab(cd lab) final

8/10/2019 Computer Drafting Lab(CD Lab) Final

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COMPUTER DRAFTING LAB(CD - Lab)

BE(2/4)MECH- B

Prepared ByMs.N.B.V.Lakshmi Kumari

Asst Prof,MED,MJCET


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Syllabus for the Computer Drafting Lab

ME 232 25 MARKS1.Introduction to Auto CAD, Setting up drawingenvironment, commands and system variables,coordinate system

2.Creating graphic primitives likepoint,line,planes,circle,Arc ,Annotation etc.

3.Creating and editing 2D object, Layers and objectProperties, Creating Dimensions, Blocks and Externalreference.

4.Working in 3D objects, Rendering and imagining, UserCoordinate system(UCS)

5.Creating a layout to plot ,documents, file formats.


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What is Drafting?

Drafting is projecting the veiws of a component

/object

What is Drawing?

A picture or diagram made with a pencil, pen

The art or skill or making such pictures or diagrams.


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HistoryAutoCAD was derived from a program called Interact,

which was written in a proprietary language (SPL) byinventor Michael Riddle

Early releases of AutoCAD used primitive entities lines, polylines, circles, arcs, and text to construct

more complex objectsThe modern AutoCAD includes a full set of basic solidmodeling and 3D tools. The release of AutoCAD 2007included the improved 3D modeling that providedbetter navigation when working in 3D,it became easierto edit 3D models.

AutoCAD 2010introduced parametric functionality andmesh modeling.

The latest AutoCAD releases areAutoCAD 2013andAutoCAD 2013 for Mac.


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Design File formats

The native file format of AutoCAD is .dwg. This and, to a lesser extent, its

interchange file format DXF Languages

AutoCAD and AutoCAD LT are available for English, German, French, Italian,Spanish, Japanese, Korean, Chinese Simplified, Chinese Traditional, Russian,Czech, Polish, Hungarian, Brazilian Portuguese, Danish, Dutch, Swedish,Finnish, Norwegian, and Vietnamese. The extent of localization varies fromfull translation of the product to documentation only. The AutoCADcommand set is localized as a part of the software localization.

Extensions

AutoCAD supports a number of APIs for customization and automation.These include AutoLISP, Visual LISP, VBA, .NET and ObjectARX. ObjectARX is

a C++ class library, which was also the base for: (a) products extendingAutoCAD functionality to specific fields; (b) creating products such asAutoCAD Architecture, AutoCAD Electrical, AutoCAD Civil 3D; or (c) third-party AutoCAD-based applications.


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System Variables:

AutoCAD stores the values for its operatingenvironment and some of its commands in systemvariables.

Each system variable has an associated type: integer,

real, point, switch, or text string. You can examine anysystem variable and change any writable system variabledirectly on the command line by entering the systemvariable name, or by using the SETVAR command or theAutoLISP getvar and setvar functions.

Many system variables are also accessible through dialogbox options.


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The Benefits of AutoCAD

Quickly create designs

Improved quality over hand drafting

Can be customized to suit the individualsneeds

Teaches a marketable skill


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The AutoCAD Screen


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X,Y What?


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X, Y Coordinate System

Every object is locatedin relation to theorigin.

Positive and negative Xaxis

Positive and negative Yaxis


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For Example.

If you have a point that islocated at (3,2) then itwould be here

And, if its negative.

If you have a point that islocated (-3,-2) then itwould be here


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Methods of giving commands in Auto Cad

There are four methods of giving commands in Auto

Cad

First is on the command line

Second is from the side screen

Third is from the command icons

Fourth is from top pull down menus

Mainly we will be using giving commands from

command line or selecting from the tool bar.


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Various Commands

LIMITS: The limits command allows to change the

upper and lower limits of the drawing area. This is the first command which is to be given in

Auto Cad

The lower limits are usually kept as 0,0 and theupper limits are 420,297

After the limits are set use the option of zoom -

>all and the units of the drawing should be

mentioned before the drawing is started ;like the

drawing mm,cm, meters, inches etc.


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AutoCAD Commands

Giving commands

Object snap

Zooming and panning

Drawing 2D shapes

Drawing 3D shapes

Editing

UCS


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Defining Points in Auto Cad

Absolute Mode

Incremental Mode

Polar Mode


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Absolute Mode

In this mode the lower left corner of the

screen is taken as Zero point.All the points of

the figure are defined withrespect to this

point.

For ex consider a square having side length of

100 mm

100

100


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For drawing this diagram in Auto Cad using

Absolute mode ca be explained as follows;

Command line

First coordinates are 10,10

Next point is 110,10



Last point is 10,10


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Incremental Mode

In this mode every previous point is taken as thereference for defining the current point

Frm last ex of the square

Command line First point 10,10

Next point is @100,0

Next point is @0,100 Next Point is @-100,0

Next Point is @0,-100


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computer drafting lab(cd lab) final

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