ortho PPT ORTHO PROJECTIONS ORTHO PROJECTIONS ORTHO PROJECTIONS

ORTHO PROJECTIONS

1. Orthographic Orthographic
ProjectionsProjections

2. OrthographicOrthographic ProjectionsProjections

Orthographic Projections are a collection of 2-D Orthographic Projections are a collection of 2-D
drawings that work together to give an accurate drawings that work together to give an accurate
overall representation of an object.overall representation of an object.

3. Defining the Six Defining the Six
Principal Views or Principal Views or
Orthographic ViewsOrthographic Views

4. Which Views to Present?Which Views to Present?
General Guidelines:General Guidelines:

Pick a Front View that is most descriptive of object Pick a Front View that is most descriptive of object

Normally the longest dimension is chosen as the width (or Normally the longest dimension is chosen as the width (or
depth)depth)

Most common combination of views is to use: Most common combination of views is to use:

Front, Top, and Side ViewFront, Top, and Side View

Any other view different from the Principal Views is called Any other view different from the Principal Views is called
an Auxiliary Viewan Auxiliary View

6. Third-angle Projection
First-angle Projection
First and Third Angle ProjectionsFirst and Third Angle Projections

First Angle – InternationalFirst Angle – International

Third Angle – U.S.Third Angle – U.S.

7. Conventional Orthographic ViewsConventional Orthographic Views
Height
Depth
Width
Front View
Top View
Right
Side
View

8. Is The Orthographic View OK?Is The Orthographic View OK?

9. Orthographic Must Be In Orthographic Must Be In
ProjectionProjection

10. Hidden and Center LinesHidden and Center Lines
•Hidden Line – used to represent features that
cannot be seen in the current view
•Centerlines – used to represent symmetry and to
mark the center of circles and the axes of
cylinders, and the axes of symmetrical parts,
such as cylinders and bolts

11. For Example:For Example:
1. Visible
2. Hidden
3. Center

12. Two-View DrawingsTwo-View Drawings

Some objects can be fully described by two Some objects can be fully described by two
views, look for: views, look for:

Symmetry or Bodies of RotationSymmetry or Bodies of Rotation
Front View Right Side View
Front
View
Right
Side

13. Other Two-View ExamplesOther Two-View Examples

14. Hints for Orthographic Projection Hints for Orthographic Projection
SketchingSketching

Identify the major features and overall Identify the major features and overall
dimensions of the objectdimensions of the object

Do Do notnot use any straight-edge devices as a pencil use any straight-edge devices as a pencil
guide when sketching by handguide when sketching by hand

Start by drawing bounding boxes with light Start by drawing bounding boxes with light
construction lines.construction lines.

Keep views aligned while sketchingKeep views aligned while sketching

15. Hints for Orthographic Projection Hints for Orthographic Projection
SketchingSketching

Title Information is required – follow Title Information is required – follow
conventionsconventions

Usage of construction lines is encouraged.Usage of construction lines is encouraged.

Mandatory for circle or ellipseMandatory for circle or ellipse

Orthographic projection: Orthographic projection:

Alignment of the views is important! Alignment of the views is important!

Will not be graded, if not alignedWill not be graded, if not aligned

16. Hints for Orthographic Projection Hints for Orthographic Projection
SketchingSketching

Map inclined and oblique faces to all three viewsMap inclined and oblique faces to all three views

Follow the precedence of linesFollow the precedence of lines

Darken all visible, hidden, and center linesDarken all visible, hidden, and center lines

17. Multi view (multi planar) projectionMulti view (multi planar) projection
Multi view is a method by which the exactMulti view is a method by which the exact
shape of an object can be represented byshape of an object can be represented by
two or more separate views produced ontwo or more separate views produced on
projection planes that are at right angles toprojection planes that are at right angles to
each other.each other.

18. Method of obtaining the viewsMethod of obtaining the views
The views of the object may be obtained byThe views of the object may be obtained by
either of the two methods:either of the two methods:
1.1.Natural methodNatural method
2.2.Glass box methodGlass box method

19. Natural methodNatural method

20. Glass Box ApproachGlass Box Approach

Most powerful technique to understand Most powerful technique to understand
orthographic projectionsorthographic projections

Suspend the object with transparent strings inside a Suspend the object with transparent strings inside a
glass boxglass box

Freeze the view from each direction (each of the six Freeze the view from each direction (each of the six
sides of the box) and unfold the boxsides of the box) and unfold the box

Animation illustrates glass-box approachAnimation illustrates glass-box approach

21. Glass Box ApproachGlass Box Approach

22. Glass Box ApproachGlass Box Approach

23. Glass Box ApproachGlass Box Approach

24. Glass Box ApproachGlass Box Approach

25. Glass Box ApproachGlass Box Approach

26. Glass Box ApproachGlass Box Approach

27. Principles of Multi view DrawingPrinciples of Multi view Drawing
1.1.The front and top views are always in line The front and top views are always in line
vertically.vertically.
2.2.The front and side views are inline The front and side views are inline
horizontally.horizontally.
3.3.The front of the object in top view faces the The front of the object in top view faces the
front viewfront view
4.4.The front of the object in side view faces the The front of the object in side view faces the
front viewfront view

28. 5.5.The depth of the top view is the same as the The depth of the top view is the same as the
depth of the side view (or views).depth of the side view (or views).
6.6.The width of the top view is the same as the The width of the top view is the same as the
width of the front view.width of the front view.
7.7.The height of the side view is the same as the The height of the side view is the same as the
height of the front view.height of the front view.
8.8.A view taken from the above is a top view and A view taken from the above is a top view and
must be placed above the front view.must be placed above the front view.
Principles of Multi view DrawingPrinciples of Multi view Drawing

29. 9.9.A view taken from right,, in relation to the A view taken from right,, in relation to the
selected front, is a right side view and must be selected front, is a right side view and must be
placed to the right of the front view.placed to the right of the front view.
10.10.A view taken from the left is a left side view A view taken from the left is a left side view
and must be placed to the left of the front and must be placed to the left of the front
view.view.
11.11.A view from below is a bottom view and must A view from below is a bottom view and must
be placed below the front view.be placed below the front view.
Principles of Multi view DrawingPrinciples of Multi view Drawing