محاضرة بعنوان Orthographic Projections

محاضرة بعنوان
Orthographic Projections
By
Dr. Akhilesh Kumar Maurya
Orthographic Projections
NOTATIONS
Types of views
View comparison
PLANES
PATTERN OF PLANES & VIEWS (First Angle Method)
rojection systems

1. First angle system
2. Third angle system
   Views arrangement
   Methods of Orthogonal Projection
3. Natural Method: Revolve the object with respect to observer
4. Glass box method: The observer moves around the object
   Glass box : Revolution of the planes of projection
   Relative orientation of views
   Summary : Problem solving steps
   Steps for Orthographic Views
   iew selection procedures
5. Orient the object to the best position relative to a glass box.
6. Select the front view.
7. Select adjacent views.
   Suggestions: Orient the object
8. The object should be placed in its natural position. NO !
9. The orthographic views should represent the true size and true shape of an object (as much as possible).
   Suggestions: Select the front view
10. The longest dimension of an object should be presented
    as a width (in a front view).
    First choice Inappropriate Second choice Good
    Use more spaceInappropriate
11. The adjacent views project from the selected front view
    should be appeared in a natural position.
    Suggestions: Select the front view3. It has the fewest number of hidden lines.
    Good Inappropriate
    Suggestions: Select the front viewSuggestions: Select an adjacent view
    Inappropriate
    Inappropriate
12. Choose the view that has the fewest number of hidden lines.2. Choose the minimum number of views that can represent
    the major features of the object.
    Necessary
    Necessary
    Hole’s information is placed on
    a separated view.
    Suggestions: Select an adjacent view
    All information is placed
    on a single view.3. Choose the views that are suitable to a drawing sheet.
    Good
    Suggestions: Select an adjacent view
    Poor
    Not enough space
    for dimensioning.
    Choose another adjacent view. Change orientation of the Good
    selected views.Summary
    View selection has 3 steps
    Orient
    the object
    Select
    front view
    Select
    adjacent viewsObject that requires only one-view
    Flat (thin) part having a uniform thickness such as
    a gasket, sheet metal etc.
    Adjacent views
    provide only a
    part’s thickness !
    1 Thick
    Cylindrical-shaped part.
    ExampleRepeat !
    Infer from CL
    Object that requires only one-view
    Example Example
    Flat (thin) part having a uniform thickness such as
    a gasket, sheet metal etc.
    Cylindrical-shaped part.Identical adjacent view exists.
    Repeat !
    Object that requires only two-view
    The 3rd view has no significant contours of the object.
    (provides no additional information)
    ExampleObject that requires only two-view
    Identical view exists.
    Example 1
    The 3rd view has no significant contours of the object.
    (provides no additional information)Object that requires only two-view
    Identical view exists.
    Example 2
    The 3rd view has no significant contours of the object.
    (provides no additional information)Example-1
    ■ Identify surfaces
    perpendicular or inclined to
    the view
    ■ Surfaces parallel to the view
    would not be visible in that
    view.
    ■ First draw horizontal and
    vertical reference planes
    (easily identifiable on
    drawing)
    ■ Start drawing from the
    reference planes.
    Steps to draw projectionsTop view
    Horizontal
    reference
    plane (HP)
    Vertical reference
    plane (VP)HP
    VP
    Front view Side view
    Top view
    Midpoint
    Front view Side view
    Top view
    Front View
    Top View
    L.h.side View
    For T.v.
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Orthographic Projections
    Example-2for T.v.
    Orthographic Projections
    Front View
    Top View
    L.h.side View
    X Y
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Example-3for T.v.
    Orthographic Projections
    Front View
    Top View
    L.h.side View
    X Y
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Example-4front View
    Top View
    L.h.side View
    X Y
    For T.v.
    Orthographic Projections
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Example-5for T.v.
    Orthographic Projections
    Front View
    Top View
    L.h.side View
    X Y
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Example-6example-7
    Pictorial Presentation Is Given
    Draw Fv and Tv of This Object
    By First Angle Projection Method
    Orthographic Projections Example-8
    All Views Identical
    For T.v.
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    14
    Orthographic Projectionsx Y
    All Views Identical
    For T.v.
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Orthographic Projectionsfor T.v.
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Orthographic Projections
    Pictorial Presentation Is Given
    Draw Fv and Tv of This Object
    By First Angle Projection Method
    Orthographic Projections
    Top View
    Example-11450
    For T.v.
    Pictorial Presentation Is Given
    Draw Fv and Tv of This Object
    By First Angle Projection Method
    Example-12 Orthographic Projectionslsv
    Pictorial Presentation Is Given
    Draw Fv and Lsv of This Object
    By First Angle Projection Method
    Orthographic Projections
    Example-13for T.v.
    Pictorial Presentation Is Given
    Draw Three Views of This Object
    By First Angle Projection Method
    Orthographic Projections
    Front View
    Top View
    L.h.side View

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