2 EN Engineering Graphics and CAD
Lecture 3 Introduction to CAD
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AutoCAD Orbit Feature
Dynamic 3D rotation Parallel (Axonometric) or Perspective Projections No Oblique Projections
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Isometric Sketching
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EN 2 Announcements
EN 2 Labs
EN 2 Labs are held in318 Anderson Hall. AutoCAD is available in the EPDC. Hours are
posted on the EPDC door in Anderson 318 is available for walk in use during TA office hours. See Blackboard for office hours. You can go to any TAs office hours Bring to lab this week; your USB Flash Memory key, or Know how to access your Tufts P drive
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Student Tufts Domain Storage
We will be using the Tufts Domain storage
a.k.a. P Drive, LAN account, Network drive Log in using your UTLN and password If you dont know your password go to the Eaton Computer Lab and get it reset 300 MB storage Access your P drive; Start, Network drives Or via Internet, webvpn.tufts.edu
Vista users with Home or Home Premium cannot access the P drive via Windows Explorer. Use http://webvpn.tufts.edu instead.
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CAD - Computer Aided Design
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CAD - Computer Aided Design
The use of computers to aid engineers, designers, and other professionals in the design, assessment, manufacture, and construction of products and constructed systems.
CAD usually implies a high graphic or geometry content.
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CAD Benefits
Create Drawings Faster
Easily duplicate drawing components Make changes faster
Verify Size and Shape (dimensions)
Dimensional accuracy Overlay of mating components
Better at modeling 3D than with paper drawings Verify function and performance
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CAD Graphics
Mechanical
Product Design and Production
AEC
Architectural Engineering & Construction Buildings, Houses, Bridges, Roads, etc.
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CAD Graphics
Electrical
Printed Circuit Boards Integrated Circuits Embedded Systems Utility Cadastral (tax) Geographic and more
Mapping (GIS)
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CAD Graphics
Use CAD to Model Geometry Logic
Floor Plan w/ Steel Details
Solid Models
Piping & Instrumentation Diagram
Printed Circuit Board Layout
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EN 2 CAD Goals
Gain an understanding of CAD technology. Gain an appreciation for how CAD can be used in
program (AutoCAD) .
engineering applications to produce better designs.
Gain some skill in using a specific commercial CAD Improve your computer literacy. Improve your visualization ability.
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AutoCAD
A popular CAD system used primarily in the AEC
(Architectural, Engineering and Construction) and Mechanical Industries
Design, analyze, and document products and systems Includes Two Dimensional (2D) and Three Dimensional
(3D) capabilities
Many options for specific engineering applications (e.g.,
piping, sheet metal, surveying, watershed analysis, road design, mechanism design)
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AutoCAD
Create Engineering CAD Models
2D geometry construction - Wireframe 3D geometry construction - Solids Title Blocks and Formatted Drawings Dimensioned and fully annotated. Make use of Paper and Model Space.
Creating Engineering CAD Drawings
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AutoCAD Demonstration
Start AutoCAD File, Close, File, New, select a template Format, Drawing Limits Zoom, All Start geometry construction
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AutoCAD User Interface AutoCAD Classic
Menu Toolbar
Icon Toolbars
3 Methods for entering commands Command Prompt
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AutoCAD User Interface 3D Modeling
Dashboard panels 4th Method
Command: dashboard
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General AutoCAD Action Process
Specify action; type command, or click on icon, or use screen menus Select Objects; pick with mouse Indicate done with selection; press Enter when done selecting objects (or spacebar or click right mouse button) Provide additional input; Respond to command prompts
Move
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that object
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General AutoCAD Action Process
Action then subject; verb-noun e.g., move, that circle and line AutoCAD also supports noun-verb e.g., take that circle and line, now move them
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AutoCAD Terminology
Drawing Limits
Are set by the user. They specify the anticipated area needed to contain the drawing to be constructed. Are calculated by AutoCAD. They specify the size and location of the smallest box that contains all of the drawing objects in a CAD file.
Drawing Extents
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The AutoCAD World
EXTENTS
EXTENTS
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AutoCAD Objects (Entities)
POINT LINE POLYLINE TEXT ARC CIRCLE ELLIPSE DIMENSION LINE and more!
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AutoCAD First Steps
Determine CAD results. Paper drawing (scale),
electronic model, 2d or 3D, precision, Determine drawing construction strategy. Enter AutoCAD (double click icon) Set Drawing Limits. Format, Drawing Limits (anticipated maximum size of drawing) Units and scale will be a function of paper size. Create and edit geometry as necessary. Add the Tufts title block (Tutblock). Plot.
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The Command Prompt
Command Prompt Command
Default Action Command Option
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The Command Prompt
Command Prompt Command
Command Option
Default value or action
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The Command Prompt
W = Fill screen with window P = Go to Previous Zoom Zoom Extents E = Fit everything on screen
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Default Action, Dynamic Zooming
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Basic Commands
1,2 Enter start point 3,10 Enter end point Circle Enter 4,2.345 Enter center point 5.5 Enter radius value Line
Enter
Zoom Enter Extents Enter Z Enter E Enter short cut for Zoom Extents
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The Menu Toolbar
Modify - use existing object to create new objects or change its size Draw - create something new Tools - general utilities View - adjust what you see on the screen File - open and save drawing, print drawing
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Menu Best for New Users
The Pulldown Menus provide the
best method for accessing features for new users.
Features in logically arranged. Draw for creating. Modify for using exisiting
geometry.
No memorization required. Options clearly listed.
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Modify and Draw Toolbars
ERASE COPY MIRROR OFFSET ARRAY MOVE ROTATE SCALE STRETCH LINE POLYLINE RECTANGLE ARC CIRCLE TEXT
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More Modify Icons
TRIM EXTEND BREAK AT PT. BREAK CHAMFER FILLET EXPLODE
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View Icons
PAN
ZOOM PREVIOUS ZOOM WINDOW ZOOM UP/DOWN
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Geometry Input Controls
SNAP TO GRID DISPLAY GRID SNAP ORTHO OBJECT SNAP DYNAMIC INPUT
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Typical AutoCAD Action Process
Choose action Select Objects Specify Base point Specify New Point
move
Enter
pick line(s) with mouse
Enter
Indicate done selecting objects
pick point on screen pick another point (or type coordinates)
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AutoCAD Coordinate Input
ABSOLUTE CARTESIAN
x,y
12.5,32.0
RELATIVE CARTESIAN
@x,y
@3,0
POLAR (r < theta)
length<angle @length<angle
4<30 @6<45
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Coordinate Input
E
FOR PT. A B D
YOU ENTER 0,0
F
C = B
A
CD 2.5 DE = 4.0
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Coordinate Input via Dynamic Input
DYN Dynamic Input is a new method for specifying relative coordinates. Polar coordinates is the default. Enter radial value Enter tab or < to proceed to angle comma to proceed to y coordinate The location of the cursor during coordinate input determines the sign of the input angle (CCW or CW)
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Coordinate Input via Dynamic Input
First value r First value r First value x
Tab second value = polar input theta < second value = polar input theta , second value = cartesian input y
Use a u to undo last point. Use Enter key to finish line segment.
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Mouse and Keyboard
Ente r
PICK
Enter
Space Bar = = Right Mouse Button = Finish Command or = Re-execute Last Command
Esc
= Cancel Current Command
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USE RIGHT MOUSE CLICK TO END COMMAND
The Enter key on the Keyboard will work too!
Enter (right mouse button) PICK
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Introduction to Object Snap
OSNAP (Object SNAP), enables the snapping
of screen picks to the ENDS and MIDPOINTS of lines, the CENTER of circles and other key points of existing geometry to enable precise construction of geometry. on/off
Click the OSNAP button in the tray to turn it
Right click to change OSNAP settings
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Introduction to Object Snap
Right click to change
OSNAP settings
Usually only these two OSNAP options should be selected.
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Popular Object Snap Options
OSNAP (Object SNAP)
q q q q q q q
END end of line or any vertex MID midpoint of line INT intersection of 2 entities CEN center of arc or circle PER perpendicular TAN tangent NODE point
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AutoCAD Object Snap
Running Object Snap default values for OSNAP are active. OSNAP is ON
If OSNAP is off you can use the immediate mode methods Use Shift Right Click to access menu Click OSNAP Toolbar
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A Practical Guide to OSNAP
Set Running Object snap options to END and CENTER Use Mouse Shift-Right-Click to get to the other options when needed
SHIFT CLICK
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Arc Creation with Fillet
Command: fillet Current settings: Mode = TRIM, Radius = 0.5000 Select first object or [Polyline/Radius/Trim/mUltiple]: r Specify fillet radius <0.5000>: .75 Select first object or [Polyline/Radius/Trim/mUltiple]: Select second object:
X X
FILLET
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Arc Creation
How many Arcs of Radius = 10 are tangent to these two circles?
R=2
R= 1
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Circle Creation with Tangent Tangent Radius (TTR)
Command: circle 3P/2P/TTR/<Center Point> Diameter/<Radius> <1.234>
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Trimming Lines and Circles
Command: trim 1 select lines that will do the trimming
X
1
TRIMMER
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Trimming Lines and Circles
Command: trim select lines that will do the trimming 1 select lines to be trimmed 2 (on the portion to be trimmed)
TRIMMEE RESULT X
2
X
1
TRIMMER
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Trimming and Extending Lines and Circles
STEP 1 Select geometry that sets the length STEP 2 Select the geometry to be trimmed or extended
trim
extend
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Building Precise 2D Geometry
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Building Precise 2D Geometry
CAD
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Tufts Title Block TUTBLOCK
Build Scale State Use
geometry full size TUTBLOCK to fit geometry actual scale factor in title block
scale factor when plotting to yield actual scale factor (if you scaled the TUTBLOCK UP by 5X, plot it with a 1/5 scale to achieve 1:1 for TUTBLOCK and 1:5 for the geometry)
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EN 2 Homework #3
Practice Create Create Create
tangent lines, trimming, extending
Gasket Drawing Mounting Plate Drawing Foundry Hook Drawing
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Homework #3a - Gasket
Experiment with the AutoCAD User Interface.
Draw, move and erase lines and circles. Experiment with coordinate input. Experiment with viewing commands.
Construct the Gasket Add the Tufts Title Block Plot the drawing
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EN 2 Homework #3b & 3c
Draw mounting plate and foundry hook
METRIC
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Custom Tufts Files for AutoCAD
These custom files will be used in EN 2 labs and homework assignments. They are available on the shared drive and Blackboard. TutBlock2007.dwg Tufts Title Block
TuftsWeighted2007.cbt used to set line
weight when printing
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Tufts Title Block
tutblock.dwg
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Adding a Tufts Title Block
tutblock.dwg is an AutoCAD drawing file of an A-size title block. Use; Insert, Block, Browse and select tutblock2007.dwg from the folder noted in lab.
Specify the location and scale. Answer prompts for name, date etc.
A read-only copy of the Tufts Title Block Is located in the 318 Temp drive.
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Editing the Tufts Title Block Tags
Double-click the border of tutblock. Select the tag and enter a new value
XNOT HERE XHERE XHERE
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Misc. Commands
Measuring distance; then specify two points
dist
Enter
Enter Moving objects; pick object(s) Enter then specify two points
move
Tools Inquiry Distance
MENU
Erasing objects; pick object(s) Enter Listing properties;
Enter
erase list
Enter
Enter
pick object(s)
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Using AutoCAD Help
help
Enter
Help
MENU
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Opening Your AutoCAD Files
Start AutoCAD Open file from AutoCAD; File, Open, and browse to your P drive (or flash drive). Save files to your P drive often (or flash drive); File, Save As. Exit AutoCAD
When using a file from Blackboard, download it first to your P drive or flash drive and then open it in AutoCAD.
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File Saving
File, Save As
but never File, Save Save your drawings to a folder (e.g., EN 2 ) on your P drive or flash drive but NOT My Documents.
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A Word About File Naming
File Names should reflect the author and the
content
It is a very good idea not to rely on one file for all
you work
If you use the same name for a file and the file becomes corrupted, you have lost all your work Save your work with different file names from time to time E.g., Bacow_HW03_v1, Bacow_HW03_v2 etc. Not homework.dwg, project.dwg,drawing.dwg
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En 2 File Naming
Use a file name like: lastname_H03 If there is more than one person with the
same last name in EN 2, add an Initial or first name
mehtah_garret_H03.dwg
It is a very good idea not to rely on one
file for all you work
smithwH03a, smithwH03b
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Plotting a Drawing
plot Set the Device if necessary to the
attached printer
File Plot
MENU
Set Paper Size, Units, Landscape Set Plot Scale (Never Plot to Fit) Check Center Plot Click Window and pick corners Plot Preview - Full before plotting
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or TuftsWeighted2007.ctb
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Adding Text
Mtext or Indicate text box corners Specify size, font
(ROMANS), etc.
Type text and click OK
when done. editir.
Use ddedit to enter te text
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Thank You
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