Lecture 3 – ITUM/DIS 102
By Ms N S W Arachchige 2/20/2017 Part I
Learning outcome
•Understanding on CAD and its advantages •Learn about the basic operation of AutoCAD •To have an idea to use AutoCAD for engineering drawing.
ITUM/DIS 102 By Ms N S W Arachchige 2/23/2017 Content ◦ Introduction to CAD ◦ Introduction to AutoCAD ◦ Evolution of AutoCAD
◦ Self assessment
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Engineering drawing :
◦ A type of technical drawing of an engineered item.
◦ It is also a graphical language
◦ A drawing can be done using freehand, instruments or computer methods.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Drawing Approaches : ◦ Freehand - For centuries, all engineering drawing was done manually by using pencil and pen on paper or other substrate. ◦ Using instruments - The drawings are usually Traditional Traditional Approach made to scale by using instruments to draw straight lines, circles, and curves concisely and accurately.
CAD ◦ Using computer - After the World War II the advent of computer-aided design (CAD), engineering drawing has been done more and more in the electronic medium
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Traditional approach
Pencils Sharpener
Eraser T - square Compass
Triangles
Erasing Circle Shield Templates Adhesive Tape
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 CAD (Computer Aided Design ) approach : ◦ The use of computer systems in tasks like creation, modification, analysis, or optimization of an engineering design is known as CAD or CADD (for Computer Aided Design and Drafting).
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Uses of CAD ◦ As an industrial art ◦ CAD is one part of the whole Digital Product Development (DPD) activity in Computer-aided manufacturing (CAM) . ◦ Used in DCC (digital content creation) ◦ Use geometrical drawings ◦ Fashion CAD software -used to show how the clothing will fit and move ◦ Landscapers use CAD software to conceptualize creations.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 CAD software Commercial Freeware and open CAD Kernels * source AutoCAD LibreCAD Parasolid by Siemens
Inventor FreeCAD ACIS by Spatial
CATIA OpenSCAD ShapeManager by Autodesk
* The kernel is the code that determines how the image render on the screen is actually described with math.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Advantage of using CAD in Engineering
◦ Gives time saving support
◦ Visualizing a model using different views
◦ Database of Drawing Aids
◦ Improve efficiency
◦ Simulation and testing facility
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 AutoCAD : ◦ A CAD software -Capable of 2D and 3D drawing. ◦ Learning AutoCAD is like learning a new language. (AutoCAD®2010)
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 AutoCAD History: ◦ Released in December 1982 as a desktop application.
◦ The first CAD system developed for PCs
◦ A commercial CAD software - By March 1986, AutoCAD had become the most widely used design application worldwide.
◦ Developed and marketed by Autodesk – Founder was John Walker with 15 co-founders. Started in 1982.
◦ By 2014 there has been 31 versions since the first release.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Start AutoCAD :
1. Click on AutoCAD icon on the desktop.
2. Select AutoCAD option on the Program menu
3. Use search facility of the OS.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Interface - AD2005 AutoC
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Interface - AD2010 AutoC
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Three options to start drawing in AutoCAD:
1. Template - Starts a drawing based on a drawing template file.
2. Wizard - Sets up a drawing using a step-by-step guide this can choose from two wizards: Quick Setup and Advanced Setup.
3. From scratch - Starts an empty drawing using default imperial or metric setting.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Steps to create a new drawing from sketch:
File >> New >> “Select template” dialog box
Select file type as “Drawing(*.dwg)” >>
Click on “Open” button. >> Then select required
measuring system Open new drawing >> screen
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Important facts on drawing screen:
◦ AutoCAD opened the graphics window using the default system units and assigned the drawing name Drawing1.dwg
◦ New drawing file automatically assigns generic name – DrawingX.dwg
◦ When saving a drawing this default name can be replaced.
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Steps to save a new drawing: File >> Save >> “Save Document As” dialog box
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Steps to open a saved drawing: File >> Open>> “Select File” dialog box
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Basic Drawing commands: Drawing commands: Line, Point, Circle, Arc, Ellipse, Pline, polygon, Hatch, Bhatch, Dtext
Utility commands: Redraw: Refreshes the program and re-displays the graphics on the screen.
Save: Saves all current changes and drawings to be saved to the disk.
End: Finishes the current session, saves the work, and takes back to AutoCAD’s main menu.
Quit: Finishes the current session, but does NOT save the changes
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Function keys:
Key Function F1 Help F2 Text/Graphics window F6 Coordinates on/off F7 Grid on/off F8 Ortho on/off F9 Snap on/off F10 Tablet on/off
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Shortcut Keys: Key Function
Ctrl + B Snap on/off
Ctrl + C Cancel
Ctrl + D Coordinates on/off
Ctrl + G Grid on/off
Ctrl + O Ortho on/off
Ctrl + T Tablet on/off
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Options to give commands in AutoCAD:
◦ By typing
◦ Using pull down menus
◦ Using toolbars
◦ Esc key is use to cancel a command
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Official Name Date of release Official Name Date of release
AutoCAD Version 1.0 1982, December AutoCAD 2009 2008, March
AutoCAD Version 2.0 1984, October AutoCAD 2010 2009, March 24
AutoCAD 2000 1999, March AutoCAD 2011 2010, March 25
AutoCAD 2000i 2000, July AutoCAD 2012 2011, March 22
AutoCAD 2002 2001, June AutoCAD 2013 2012, March 27
AutoCAD 2004 2003, March AutoCAD 2014 2013, March 26
AutoCAD 2005 2004, March AutoCAD 2015 2014, March 27
AutoCAD 2006 2005, March AutoCAD 2016 2015, March 23
AutoCAD 2007 2006, March AutoCAD 2017 2016, March 21
AutoCAD 2008 2007, March AutoCAD 2018 2017, __/__
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Part II
Learning outcome
•Good understanding about the essential drawing settings. •Understand the coordinate system in AutoCAD. •Develop skills to use AutoCAD help facility.
ITUM/DIS 102 By Ms N S W Arachchige 2/23/2017 Content
◦ AutoCAD Drawing standards ◦ Coordinate system ◦ AutoCAD help
◦ Self assessment
ITUM/DIS 102 By Ms N S W Arachchige 02/23/2017 Set up a drawing standards :
◦ It is needed to set some AutoCAD variables, options and parameters to own values before starting a drawing.
◦ There are literally hundreds of these settings and options.
◦ It is best to set these options first and then save empty drawing as a template (*.dwt).
◦ Then start a new drawing with this template as your options (standards) are already set.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Gridlimits - The default grid display boundary
Imperial units A new drawing based on the imperial measurement system =>Gridlimits is 12 x 9 inches.
Metric units A new drawing based on the metric measurement system => Gridlimits is 420 x 290 millimetres.
** Note that default setting for AutoCAD is Imperial.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 A workspace ◦ AutoCAD provides a task-oriented drawing environment. ◦ It comprise with only the tools and interface elements necessary to accomplish the tasks relevant to that environment. ◦ By default, AutoCAD has four workspace configurations: 2D Drafting & Annotation 3D Modeling AutoCAD Classic Initial Setup Workspace
Tools >> Workspaces >>Select one from four
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Drawing Area Setup
Setting the Drawing Limits controls the extents of the display of the grid. It also serves as a visual reference that marks the working area. Format >>Drawing Limits >> The command line displays : “Reset Model Space Press enter to accept default coordinates << Limits: Specify >> lower left corner or [On/Off] The command line displays : <0.00,0.00>:” ““Specify upper right corner >> Press enter to accept default coordinates <12.00,9.00>:” ** Note that this setting does not limit the region for geometry construction. Press Grid button on status bar and [View] >>[Zoom] >>[All] to see the change Some settings that commonly stored in template files: ◦ Unit type/formats and precision ◦ Drawing limits ◦ Snap, Grid and Ortho mode settings ◦ Layer organisation ◦ Title blocks, boarders and logos ◦ Dimension styles ◦ Text styles ◦ Line types
** It is possible to open an existing drawing (*.dwg) and use it as a template.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Determine the system of units within the system before creating the first geometric entities.
To set the units format and precision Application button >> Drawing Units >>
Drawing Units dialog box, under Length, select a unit format and precision >> Click OK. ◦ The Sample Output area shows an example of the unit format at the current precision.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 The importance of Visual reference (Snap & Grid)
In the drawing space we can draw freehand sketch which is known as the interactive method, where we use the cursor to specify locations on the screen.
But to sketch a technical drawing it would be helpful to know what one inch or one meter looks like on the screen while we are creating entities. AutoCAD®2010 provides us with many tools to aid the construction of our designs ◦ E.g. the GRID and SNAP options can be used to get a visual reference as to the size of objects and learn to restrict the movement of the cursor to a set increment on the screen.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 The GRID and SNAP options can be turned ON or OFF through the Status Bar.
The GRID option creates a pattern of dots that extends over an area on the screen. The default grid spacing, which means the distance in between two dots on the screen, is 0.5 inches.
The SNAP option controls an invisible rectangular grid that restricts cursor movement to specified intervals. The default snap interval is 0.5 inches, and aligned to the grid points on the screen. To set the Drafting Settings
Tools >> Drafting Settings>>
In dialog box specifies: 1. Snap and Grid settings. 2. Angle settings for a polar snap pattern 3. Geometric properties for which object snap points are created 4. Controls pointer input, dimension input, dynamic prompting, and the appearance of tooltips >> Click OK.
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Setting tracking modes
snap grid ortho mode polar tracking object snap Object snap tracking
ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Mode (Function Description Key) Snap (F9) With Snap mode turned on AutoCAD only allows you to pick points which lie on a regular grid. Snap makes the crosshairs jump to points on a defined grid. Grid (F7) A regular pattern of dots displayed on the screen . ortho mode Ortho is short for orthogonal, which means either (F8) vertical or horizontal. polar tracking Polar Tracking allows to snap into whatever angles you (F10) choose to configure. object snap (F3) Provide a way to specify precise locations(Anchor points , eg, end points, center, corner etc…) on objects. Object snap Object Snap Tracking (OTRACK) works Tracking (F11) with OSNAP and POLAR to help align new points with existing locations in the drawing. World Coordinate System (WCS) - AutoCAD uses a fixed Cartesian coordinate system (X, Y and Z).
User Coordinate System (UCS) – User can define a UCS by altering the location and orientation of the origin and the XY plane. The UCS can move and rotate. ◦ By default, UCS and WCS are coincident in a new drawing. ◦ It is more convenient to create and edit objects based on the movable UCS.
The UCS icon is displayed either at the UCS origin or in the lower-left corner of current view. ◦ It indicates the location and orientation of the UCS
Command: UCS
ITUM/DIS 102 By Ms N S W Arachchige AutoCAD UCS icon
In AutoCAD®2010, the UCSicon is displayed in various ways to visualize the orientation of the drawing plane.
View >> UCSicon ,Properties Absolute coordinates (format X,Y). ◦ Useful when we know the exact location of a point. Command: Line Specify first point: 0,0 Specify next point: 10,7
Relative coordinates (Format @X,Y ) ◦ useful when we know the displacement of a point in relation to the previous point Command: Line
Cartesian coordinate Specify first point: 10,7 Specify next point: @4,-4
Polar coordinate (Format @distance ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Five methods of defining positions 1. Interactive method: Use the cursor to select on the screen. 2. Absolute coordinates (Format: X,Y): Type the X and Y coordinates to locate the point on the current coordinate system relative to the origin. 3. Relative rectangular coordinates (Format: @X,Y): Type the X and Y coordinates relative to the last point. 4. Relative polar coordinates (Format: @Distance 5. Direct Distance entry technique: Specify a second point by first moving the cursor to indicate direction and then entering a distance. Use of coordinate system in technical drawing Drawing rule : The design should be created at full Size using real-world units. The task of determining a scale factor that the design will fit on a sheet of paper is taken care of by the CAD system. The designers and CAD operators need to concentrate their attention only on the design. ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Cursor will jump/snap here Click on line tool then give coordinates in the command line: _line Specify first point: 0,0 Specify next point or [Undo]: 5.5,0 Specify next point or [Close/Undo]: @0,2.5 Left click once on the coordinates display area to switch to using the WCS Create the next line by picking the location , move the cursor to world coordinates (8,2.5 ), on the screen and press Enter. Then on command line: Specify next point or [Close/Undo]: @3<90 Specify next point or [Close/Undo]: @-1.5,1 Move the cursor directly to the left of the last point and use the direct distance entry technique by entering 6.5 Use the Close option to connect back to the starting point. Inside the graphics window, right-mouse-click and a popup menu appears on the screen, select Close. Selecting an object on the drawing space: ◦ Click – click on an entity will select that entity ◦ Click & drag from left – entities fully inside the selecting rectangle will get selected ◦ Click & drag from right – entities even partially inside the selecting rectangle will get selected Control view of the drawing space ◦ Zoom – mouse wheel up & down will result zoom-in & zoom-out of the drawing space. ◦ Pan – squeeze the mouse wheel and drag allows to pan ◦ Orbit – shift & squeeze mouse wheel allows to orbit the drawing space. ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 To learn more about a command or system variables use AutoCAD’s HELP system. How to open the help system?: 1. Method 1: Start a command and press the F1 key. 2. Method 2: Select HELP menu and select HELP from the drop down menu. 3. Method 3: Press F1 while no command is pending. HELP will start at the welcome page. ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Part III Learning outcome •Develop skills on advanced features in AutoCAD. •Obtain basic knowledge on 3D designing using AutoCAD. ITUM/DIS 102 By Ms N S W Arachchige 03/092017 Content ◦ Learning outcome ◦ Input Methods ◦ Editing 2D designs ◦ Layers ◦ Polylines ◦ Blocks ◦ Hatching ◦ Introduction to 3D views ◦ Self Assessment ITUM/DIS 102 By Ms N S W Arachchige 03/09/2017 Every drawing action is a set of input data. Types of input data: ◦ Coordinates ◦ Lengths ◦ Angles ◦ Commands ◦ Options There are three input methods to enter these inputs ◦ Tools ◦ Command line ◦ Dynamic input ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Dynamic input method: ◦ Two types: Pointer input Dimension input ◦ Turn on/off: Toggle button F12 ◦ To control dynamic input: Right click on toggle button Dyn >> Settings Before editing we have to create a drawing using input methods. We might also need to use drafting tools (object snap tracking, polar tracking) to help to define the precise position. Modifying / Editing an object is bit different than creating Editing objects is a common part of all design tasks. ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Menu panel Tool bar Basic steps 1. Select entity 2. Select tool 3. Input modifying data ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Methods to select an entity ◦ Select using mouse events ◦ Select using command line >> Type W and press ENTER Grips / Anchor points ◦ Grips are selectable points on a geometry. Grips appear when you select an object and no command is currently active. eg. No grips when W command is active Editing command types ◦ Transformation Commands -allows the user to select a group of objects that need to be transformed in one way or another. ◦ Deletion Commands - used to delete objects and entities. ◦ Error Recovery Commands - bring back errors made during the editing process. ◦ Commands that Change Existing Entities - allow different editing changes to be made to existing entities. ◦ Enquiry Commands -used to obtain information a drawing’s object’s position and nature. Transformation Commands : ◦ Eg: Move, Copy, Rotate, Scale, Mirror, Stretch , Array, Offset Deletion Commands: ◦ Eg: Erase, Oops Error Recovery Commands ◦ Eg: U, Redo, Undo Commands that Change Existing Entities ◦ Eg: Change, Pedit, Break, Trim, Extend, Fillet, Chamfer, Divide Enquiry Commands ◦ Eg: List, Dist, Area ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Example for Transformation Commands : ◦ Copy command - Method 1 – Using Tools Select an entity Select command by right click on the selected entity. Right click on drawing space and select “Past” Move cursor to new copy position and press enter. Copy command - Method 2 – Using Dynamic input Select Move command Select object and press enter The Dynamic Input interface prompts you to Specify a base point. Enter data in Relative Coordinate mode and places the values in the correct input fields. Press ENTER Copy command - Method 3 – Using Command line ◦ Type copy command ◦ Click on object/objects to be copied ◦ Press enter ◦ Specify base point ◦ Give coordinates and press enter ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Example for Deletion Commands: ◦ Erase command - Using Tools Click Erase tool from modify panel on home ribbon tools Select the object to erase. Press [Enter or Spacebar] to confirm. ◦ Erase command – using command line Type ERASE or E and press Enter ◦ Erase command – using delete button Pressing [Delete] key also activate Erase tool. ◦ ** Oops command: use to reload the objects erased. Example for Error Recovery Commands: ◦ Undo command – Method 1 - Select the Undo button on quick access bar once and it activates a single operation of undone. Method 2 - Use U in the command line and press enter to undone. Can continue to press ENTER to repeat the Undo command. ITUM/DIS 102 By Ms N S W Arachchige 02/02/2017 Example for Commands that Change Existing Entities ◦ Trim command Method 1 - Home tab > Modify panel > Trim – Select the objects to serve as cutting edges and press ENTER (or press ENTER without selecting any objects) Select the objects to trim. Press ENTER to end the command. Example for Enquiry Commands ◦ List command – observe what information is displayed for each unique object Type the List command and Enter. Select an object and press Enter. Observe the information listed in the AutoCAD Text Window. Press F2 to close the text window. Ref : 1. https://goo.gl/vnuQck 2. https://goo.gl/EUVI1i Thank you. ITUM/DIS 102 By Ms N S W Arachchige 03/09/2017