The document discusses multi-view drawings and orthographic projection. It provides the following key points: - Multi-view drawings show two or more 2D views of a 3D object to describe its shape and dimensions and serve as the main communication method between designers and manufacturers. - Orthographic projection uses perpendicular lines of sight to project features of an object onto imaginary projection planes to create 2D views, with a total of six views for a 3D object. - To sketch a multi-view drawing, the required space is calculated, construction lines are used to layout views, and object lines are drawn within the views to identify visible edges.

1. Multi-View Drawings

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

3. Multiview Drawing

4. Width, Depth, and Height
All three-dimensional objects have width,
height, and depth.
Width is associated with an object’s side-to-
side dimension.
Height is the measure of an object from top-
to-bottom.
Depth is associated with front-to-back
distance.

5. Width, Depth, and Height

6. Width, Depth, and Height
45°

7. 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.

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

9. 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.

10. 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.

11. Orthographic Projection
• Start by focusing
only on the front
projection plane. 2
• A person standing
3
in front of the
object would see 1
only the five s
t
igh e 4
of ngl
corners identified lin 0° a ction
e
9
at proje e 5
in black. to plan

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

13. 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.

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

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

16. Sketching a Multiview Drawing
• Given the overall
dimensions of the
object, a pencil, and a
sheet of graph paper, a
sketching multiview
drawing can be easily
done using points,
construction lines, and
object lines.

17. Sketching a Multiview Drawing
Step #1: Calculate the amount of space that
the views will take up.

18. Calculating Required Space
Overall Multiview
12 Sketch Height?
space
s
Overall Multiview
Sketch Width?
18
spaces

19. Sketching a Multiview Drawing
Step #1: Calculate the amount of space that
the views will take up.
Step #2: Layout the boxes within which the
individual views will occur using
points and construction lines.

20. Construction Line Layout

21. Sketching a Multiview Drawing
Step #1: Calculate the amount of space that
the views will take up.
Step #2: Layout the boxes within which the
individual views will occur using
points and construction lines.
Step #3: Identify the visible edges by
drawing object lines on top of the
construction lines.

22. Object Line Layout

23. IPod Technical Drawing

24. Requirements in pencil = fixable.
for MVDs
• The lines should be neatly done
• The lines should be neatly done – not too thick.
• A straight edge is needed for straight lines – no free hand.
• The drawings are done to a labelled scale.
• The object’s actual dimensions are labelled.
• Object Lines (seen) are done in black ---------.
• Hidden Lines are dashed -- -- --.
• The metric dimensions line up: width of the top/front views
height of the
front/right views
• The three views are labelled – Top/Front/Right.

25. A Question…
• Each of the
blocks at right
has the same
overall
dimensions
and color.
• What else do
they have in
common?

26. A Question…
Each of the
blocks at right has
They all have
the same overall
dimensions and
identical top
color.
views!
What else do they
have in common?