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Engineering Graphics H193

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					                           First-Year Engineering Program




            Engineering H191
Engineering Fundamentals and Laboratory I

                Week 02 Day 03
      Computer Aided Design (CAD) with
                Inventor® 2010
    Chapter 3: Constructive Solid Geometry
          Review and New Material
                                    First-Year Engineering Program



                  Evolution of CAD

• 2D Wireframe – Points and Lines

• 3D Wireframe – Points and
  Edges

• Surface Modeling – Adding a
  surface to 3D Wireframe

• Solid Modeling – Constructive
  Solid Geometry
   – Assembling primitive solids
      by adding or subtracting


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                         Evolution of CAD
• Feature-Based Parametric Solid Modeling
   – A design process
        •     Sketch a 2D shape
        •     Add Dimensions for size
        •     Extrude or revolve the shape to make a solid
        •     Repeat as needed while adding or cutting away features
   – Dimensions can be changed at any time in the
     design process and the part will be updated
   – This approach is typical for parametric modeling
     programs – these include Pro Engineer, Solid
     Works, Solid Edge, CATIA, and other software
     packages.
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              Constructive Solid Geometry
• Objects are built from Primitive
  Solids



     – Join or Union



     – Cut or Difference



     – Intersection or Common
        Material
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    With the rectangular solid and the cylinder, we produced the
    figures on the previous page by doing a union, a difference,
    and an intersection. The setup for the intersection is shown here.




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              Creating a More Complex Object

   How would
   you make
   this object
   as a set
   of geometric
   primitives?

   Always plan
   ahead!


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              Develop a Modeling Strategy
• First - do it individually
• Second – compare to the others at your table
• Which strategy had the fewest steps?




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              This is Inventor’s opening slide



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                                 First-Year Engineering Program

              Select Metric




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                Default Sketch Plane
• When you use the default sketch plane to begin with, you need
  to begin with a profile from the proper view or the isometric will
  be rotated from what you desire.


English system parts produce a FRONT view in the
  isometric.
Metric system parts produce a TOP view in the
  isometric.

   If you forgot how to redefine the isometric view, refer back to
   slide 24 of lecture 04

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                    Select “Tools”, then “Document
                    Settings”, then “Sketch” to change
                    the grid spacing for the sketch




Document Settings




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        Begin Construction: Draw Rectangle




Use “General Dimension” to get current size of rectangle
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          Use Document Settings Again: Units




 Use Document
Settings (Units) to
   Set Display
     Precision




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                     Editing the Sketch




Single click on the dimension to bring up a dialog box
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      Setting Correct Dimensions on Sketch




Figure changes to match the dimensions and the dimensions
have the correct precision.
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         If Your Sketch Expands Beyond Your Window


  The “Zoom All” Button on
  the Standard Toolbar will
  rescale your window to
  the size of your sketch


Or you can use the “Zoom” Button to
rescale your window as you wish
from the options in the pull down
menu

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       If Your Sketch Expands Beyond Your Window

The “Zoom All” Button is also under the
the View tab




The same drop down menu can be found here
also
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              Going from Sketch to Model

                                                        Right click
                                                        to bring up
                                                        menu –
                                                        select
                                                        ‘Finish
                                                        Sketch”

                                                        Go to Part
                                                        Features –
                                                        ‘Extrude’
              With ‘Extrusion’ the “Base Sketch” becomes …

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          Solid Model of the Base is Created




                     Extrusion 1
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                     Click on ‘+’ to see Sketch 1            19
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   The Next Sketch Must Be on the Bottom Surface




                                           Use “Dynamic
                                           Rotate” to get
                                           Bottom surface




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              Bottom Surface Revealed




    Bottom
    Surface




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                   Sketch on Bottom Surface
Center of
Line




                                                                Corner and
    Select Circle from Sketch Panel                             End of Line
    Find green dot that indicates center of the line
    Left Click once, drag circle to edge (another green dot)
    Green dots indicate adding constraints!
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                                           First-Year Engineering Program

   • Finish Sketch 2 and use the Home Icon to see the top side
   • Choose “Extrude”
   • Pick the circle for your profile to extrude
   • Set the Distance to 40 mm, click left and right arrows to see
     a preview of the extrusion




       Choose Right Arrow and Click OK.
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              This Completes Extrusion 2




                          Note: Extrusion 2 has Sketch 2
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                                Associated with It.          24
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      Three More Extrusions (Cuts) Are Executed to
                 Complete the Drawing
                                                      Extrusion 4
Extrusion 3




                                                    Extrusion 5




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                    Dimensioning Caution:
Enter dimensions explicitly, even if they appear correct. Constructive
Solid Geometry is not able to line up features if they are off by just
.0000000001




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              Today's Assignment

• Drawing 9 – INV Ch 3 in text example




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posted:5/8/2013
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