Lecture 2

Question 1

What are the three drawing methods?

Answer 1

Freehand, Mechanical tools, and Computer Aided Design

Question 2

Line of sight versus Plane of projection?

Answer 2

Line of Sight
• An imaginary ray of light between the observer’s eye and the
object
• Start at a single point for perspective projections and are
parallel in parallel projections
• Plane of projection
• An imaginary flat plane upon which the image created by the
lines of sight is projected
• Visualize this as a piece of paper or computer screen

Question 3

Perspective Projection Properties

Answer 3

Representation of
objects based on rule of
distance
• More distant objects
are smaller
• Shape is distorted
• Do not show the true
dimensions of objects

Question 4

Parallel Projection Properties

Answer 4

• Most commonly
used in engineering
graphics
• Show accurate
dimensions

Question 5

Describe a oblique projection

Answer 5

• Front face is drawn as a true shape on the
horizontal and vertical axes
• The third axis is usually drawn at 45◦

Question 6

Describe orthographic projection.

Answer 6

A parallel projection where the plane of projection

is perpendicular to the lines of sight

Question 7

Describe a multi view drawings

Answer 7

Pictorial drawings (perspective or orthographic)
distort dimensions and/or angles
• Multiview drawings show the true size and shape
of the dimensions shown

Question 8

What angle projection is used in Europe?

Answer 8

First angle projection
is used in Europe
(eye-object-image)

Question 9

What angle projection is used in North America?

Answer 9

Third angle
projection is used in
North America
(eye-image-object)

Question 10

Name a few different line types.

Answer 10

Object line
Hidden line
Center line
Dimension line

Question 11

What is a section View?

Answer 11

Section views:
• Clarify details
• Show internal feature clearly
• Reduce the number of hidden detail lines
• Aid dimensioning
• Show cross-section shape

Question 12

How to dimension?

Answer 12

• Drawings need to convey all of the information
required for construction
• Standards and conventions should be followed
• Dimensions should be placed so they are easily read
• The drawing must include the minimum number of
dimensions required to construct
• A given dimension should not be stated more than
once
• No one using the drawing should have to calculate a
dimension