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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
Next point is 110,110
Next point is 10,110
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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