1. MECHANICAL DRAWING
MULTIVIEW DRAWINGS

2. Different views of an object
Objects may be drawn in different ways
Multiview
Pictorial
Better for showing true size and shape
Each view only shows two dimensions
Better for visualizing the object
All three dimensions shown on a single view

3. Multiview Drawing

4. Multiview Drawing
A multiview drawing is one that shows two or more two-dimensional views of a three-dimensional object.
Multiview drawings provide the shape description of an object. When combined with dimensions, multiview drawings serve as the main form of communication between designers and manufacturers.

5. Multiview Drawing
Another name for orthographic projection is multiview drawing
Involves visualization and implementation
Ability to see clearly in the mind’s eye an object
Process of drawing the object

6. Angles of Projection First-angle projection
Used by many European countries
Object is projected onto planes from the first angle or quadrant
Front view projected to vertical plane
Top view projected to horizontal plane
Left-side view projected to profile plane

7. Angles of Projection Third-angle projection
Standard for the United States
Third quadrant is used for projection
Front view projected to vertical plane
Top view projected to horizontal plane
Right-side view projected to profile plane

8. Choosing Views Most commonly used views
Front View
Top View
Right Side View
Most descriptive view is typically designated as the Front View

9. Choosing Views
Complex objects require three views to describe its shape
Simple objects can be described with two views
Ex: Soda Can
Thin objects can be described with only one view
Depth is given in a note
Ex: Erasing Shield

10. Placement of Views
Views should be visually balanced within the working space

11. Steps for Centering a Drawing
Draw border and title block using light construction lines
Draw diagonal lines from corners of border

12. Layout of Views

13. Steps for Centering a Drawing
Add:
Length 5.13
Space 1.50
Width 2.00
Horizontal 8.63
Height 3.00
Space
Width
Vertical 6.50

14. Steps for Centering a Drawing
Draw a box the size of all views
Measure from the center:
Half the width
Half the height

15. Steps for Centering a Drawing
Draw in views using light construction lines

16. Adding Details Add holes and features
Transfer horizontal and vertical features
Use miter line to transfer depth

17. Straight Edges
Edges that are parallel to a plane of projection appear as lines
Edges that are inclined to a plane of projection appear as foreshortened lines

18. Curved Edges
Curved edges project as straight lines on the plane to which they are perpendicular
Curved edges project as curved lines on the planes to which they are parallel or inclined

19. Normal Surfaces
Normal surfaces appear as an edge in two opposite principal views, and appear a surface in all other principal views.

20. Inclined Surfaces
Inclined surfaces appear as an edge in two opposite principal views, and appear foreshortened (not true size) in all other principal views.

21. Oblique Surfaces
Oblique surfaces do not appear either as an edge or true size in any principal view.

22. Intersections & Tangencies
Where a curved surface is tangent to a plane surface, no line should be shown where they join

23. Intersections & Tangencies
Where a plane surface intersects a curved surface, an edge is formed

24. What is Multiview drawing?
Drawing more than one orthographic view of an object on the same page
Ortho (straight) + graphic (drawing)
An orthographic view is drawn looking straight at one side of the object (at 90° to it)
Line of sight
Projection plane
Object

25. Orthographic Projection
Orthographic projection is a technique that is used to create multiview drawings.
Orthographic projection is any projection of the features of an object onto an imaginary plane of projection. The projection of the features of the object is made by lines of sight that are perpendicular to the plane of projection.

26. Orthographic Projection
The best way to understand orthographic projection is to imagine an object contained inside a glass box.

27. Orthographic Projection
There is a total of six glass walls surrounding the object. Each wall represents a projection plane onto which a two- dimensional object view will be created.

28. Projection Plane
A projection plane, also referred to as a plane of projection or picture plane, is an imaginary surface that exists between the viewer and the object.
The projection plane is the surface onto which a two-dimensional view of a three-dimensional object is projected and created.

29. Orthographic Projection
Start by focusing only on the front projection plane.
A person standing in front of the object would see only the five corners identified in black. 2 3 1 4
line of sight
at 90° angle to projection plane 5

30. Orthographic Projection
Projection lines are used to project each corner outward until they reach the projection plane.

31. Projection Lines
A projection line is an imaginary line that is used to locate or project the corners, edges, and features of a three-dimensional object onto an imaginary two-dimensional surface.

32. Orthographic Projection
The visible edges of the object are then identified on the projection plane by connecting the projected corners with object lines.

33. Orthographic Projection
The orthographic projection process is then repeated on the other projection planes.

34. A Question…
Each of the blocks to the right have the same overall dimensions and colors.
What else to they have in common?

35. They all have identical top views!
Answer ….
They all have identical top views!

36. HIDDEN LINES MUTLIVIEW DRAWINGS
We place hidden lines in a drawing to do the following things:
Show hidden features
2. Clarify the position and shape of features
3. Make the “plate” more readable
(NOTE: The term “plate” refers to a finished drawing.)

37. Cubes (like these dice) have 6 sides
How many views?
Cubes (like these dice) have 6 sides
Since each side of the die will have its own view…
Front
then there must be SIX possible orthographic views!

38. Cubes (like these dice) have 6 sides
How many views?
Cubes (like these dice) have 6 sides
Top
Since each side of the die will have its own view…
then there must be SIX possible orthographic views!
Front

39. Cubes (like these dice) have 6 sides
How many views?
Cubes (like these dice) have 6 sides
Since each side of the die will have its own view…
Right Side
then there must be SIX possible orthographic views!
Front
Top

40. Cubes (like these dice) have 6 sides
How many views?
Cubes (like these dice) have 6 sides
Since each side of the die will have its own view…
then there must be SIX possible orthographic views!
Front
Back
Top
Bottom
The Front, Top, and Right Side are the views that are usually drawn.
Right Side
Left Side

41. All the views MUST be arranged correctly
Where do the views go?
All the views MUST be arranged correctly
Imagine “unfolding” the cube to get proper view alignment.
The back view can be placed in any of these four locations.

42. How does this work on other objects?
Place the object in a glass box
Then “unfold” the box
Front view is always central
Top view goes above
R.Side view goes to the right

43. What about details you can’t see?
Hidden lines show details that are not seen in all views
Project from hidden detail to the other views
Draw hidden lines (dashed) to show the detail

44. ANIMATED EXAMPLES

45. Multiview Drawing REVIEW
An orthographic view is drawn looking straight at one side of the object (at 90° to it)
There are 6 possible orthographic views:
Front, Back, Top, Bottom, Left Side, Right Side
The Front, Top, and R.Side views are usually all that are drawn
Hidden lines show details you can’t see in all views

46. Centering a Multiview Drawing Review
Make a sketch of the views needed for the drawing.
The space between the views is 1 ½”
What are the measurements needed to center the drawing?
What is the overall size of the box for the views?

47. Centering a Multiview Drawing Review
3.50
1.5
6.75
1.75
6.50
1.5
3.50
11.50

48. Layout of the 6 Views
Sketch the layout of the 6 views of this object and label the views.
TOP
REAR
L. SIDE
FRONT
R. SIDE
BOTTOM