Chapter 5Orthographic ProjectionSix Standard ViewsView Placement (3rd angle projection)Revolving an Object to Produce the Six Basic ViewsThe Glass Box MetaphorProjection of an ObjectSlide 8Unfolding the Glass boxThird Angle Projection:Glass Box MethodDEMOHidden LinesPrecedence of LinesExampleHands-On 4Chapter 5MultiviewSketching & ProjectionPrint handoutsSelect File, PrintEdit the following selections to read:Select the OK buttonOrthographic ProjectionA system of drawing views of an object using perpendicular projectors from the object to a plane of projection (I.e. paper)Six Standard Views Top, front, right side, left side, back and bottom–Front»Usually shows most detail»If applicable – should show object in operating condition (I.e. car)View Placement (3rd angle projection)Front view usually shows the most detailProjection LinesWhy must views be arranged so that they align?To make it possible for someone to interpret the drawing.Revolving an Object to Produce the Six Basic ViewsThe Glass Box MetaphorImagine that the object you are going to draw is positioned inside a glass box, so that the large flat surfaces of the object are parallel to the walls of the box.–2 horizontal planes –2 frontal planes –2 profile planesFrom each point on the object, imagine a ray, or projector perpendicular to the wall of the box forming the view of the object on that wall or projection plane.–2 horizontal planes (top and bottom views)–2 frontal planes (front and back views)–2 profile planes (right and left side views)Projection of an Object8Projection of an ObjectUnfolding the Glass boxFor Third Angle Projection (the method in the U.S.)Imagine that the walls of the box are hinged and unfold the views outward around the front view.This will give you the standard arrangement of views for 3rd Angle Projection which is used in the US, Canada, and some other countries.10Third Angle Projection:Symbol forthird angle projection shown on dwgFirst Angle Projection:Symbol forfirst angle projectionGlass Box Method12DEMOIf a point, line or plane is in one view, it must be in all the views.13Hidden Lines14Precedence of LinesWhen visible lines, hidden lines and center lines coincide remember:–Visible lines take precedence over hidden lines– Hidden lines take precedence over center lines, For example:Figure 5.3215ExampleDo Hands-On 3 together–Need»HB pencil»Engineering Calculation Paper»Model»Instructions (Sept. Schedule of Assignments in Angel)–Follow instructions»Remember specs for the border & title block are included in the Penn State Erie Graphics Standards and in Handouts folder in AngelLabel–Views – TOP, FRONT, etc.16Hands-On 4Instructions on the
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