TECH 104 – Technical Graphics Communication
Week 1:
Introduction to Engineering
Graphics Communication
Development of Engineering
Graphics
Multiview Drawings
Francesca (1420-92)
Cartesian Coordinates
Descartes (1596-1650).
Engineering is <90%
graphically based.
Engineering Drawing
What you will learn






Visualization
Graphics Theory
Standards
Conventions
Tools
Applications
TECH 104 – Technical Graphics Communication
The “Language”
Lines may be defined as…….
1. A series of points in space organized in a rational order
2. The shortest distance between two points
3. The geometry created by the intersection of two planes or
surfaces
4. A set of points organized that have length and direction,
but no thickness
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Parallel lines will always maintain
the same distance from each other
throughout their entire length, and
NEVER touch!
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Non-parallel lines do not maintain
the same distance from each other
throughout their entire length, and
may either touch, or eventually
cross each other.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Perpendicular lines are at 90
degrees to one another.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Intersecting lines cross each other
at any angle.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Tangent lines are created when:
1. A curved and straight line
meet, and….
2. The two lines intersect at only
one point, and….
3. A smooth transition into one
line can be generated.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Lines will appear as edges when there is an
intersection of two planes or surfaces.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Tangent conditions may appear in
both 2D and 3D geometry….
Figure A shows a tangent being
created at Point C
Figure B shows Tangent F being
identified as the intersection point
between the 2 circles.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Here we can see that Line VT is
lying tangent to the cone.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines come in all types and shapes:
Can you explain why Example A is
tangent, but Example B is not??
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Circles are considered the most perfect form
geometric shape. All circles are made up of
many parts…
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
A parabola’s shape can be generated from a 3D
cone and 2D plane….
Notice that the parabola’s shape is
symmetrical (mirror image of
itself), and that it has a focus point
inside the arc of the line. The
cutting plane is always parallel to
the slope of the cone.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Parabolas have many engineering uses and
shapes….
As the shape of the curve
of the parabola changes, it
allows for more diverse
applications.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
The ellipse is generated in much the same way
as the parabola….
Notice that the ellipse’s shape is
symmetrical (mirror image of itself),
like the parabola.
However, the ellipse has no focus point
identified inside the arc of the line, and
the cutting plane is NOT parallel to the
slope of the cone.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
A circle may appear as an ellipse when the
object is not perpendicular to the line of sight.
While the circle’s geometry remains
true shape and size, our view of its
shape appears more oval as the
object is rotated from its 90 degree
position.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Lines can be set at angles
to points or other lines…
Lines set at angles help us understand
the relationship of other lines, or the
geometry’s position in space.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Quadrilaterals have two main characteristics:
1. They are CLOSED entities,
2. They have 4 sides.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Polygon means “many sided”:
Most polygons have names based on the
number of sides they have.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
2D and 3D Space:
Let’s take a few minutes to see how lines and points are used
to organize space…..
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
If we take the centre of the universe as our home
position (X=0 and Y=0) , we are able to map out the
coordinate vertices of any object from that point and
assign them addresses so they may be easily located.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
However, as the universe is not 2-dimensional, we must take
into consideration a 3rd axis (Z) that represents its volume.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Since the computer ALWAYS remembers that its home is
(0,0,0), we may locate any point in space, or on a 3D model,
by referencing home.
Week 1: Engineering Graphics Overview
TECH 104 – Technical Graphics Communication
Each point on a 3D model
has its own address in
space that is designated
by an X, Y, & Z value.
Here we can see the
address of each vertex.
Example: (4, 3, 0)
Week 1: Engineering Graphics Overview
Standard Sheet Sizes
TECH 104 – Technical Graphics Communication
Week 2:
Sketching, Text, and
Visualization
Week 1: Engineering Graphics Overview