TECH 104 – Technical Graphics Communication Introduction to Engineering Graphics Communication

TECH 104 – Technical Graphics Communication

Introduction to Engineering Graphics

Communication

Development of Engineering Graphics

Multiview DrawingsFrancesca (1420-92)

Cartesian CoordinatesDescartes (1596-1650).

Engineering Design Process is (92%)graphically based.

Engineering Drawing

What you will learn

Visualization Graphics Theory Standards Conventions Tools Applications


Lines may be defined as…….

1. The shortest distance between two points

2. The geometry created by the intersection of two planes or surfaces

3. A set of points organized that have length and direction, but no thickness

The “Language”


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!



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.



Perpendicular lines are at 90 degrees to one another.



Intersecting lines cross each other at any angle.



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.



Lines will appear as edges when there is an intersection of two planes or surfaces.



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.



Here we can see that Line VT is lying tangent to the cone.



Can you explain why Example A is tangent, but Example B is not??


Circles are considered the most perfect form geometric shape. All circles are made up of many parts…


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.


Parabolas have many engineering uses and shapes….

As the shape of the curve of the parabola changes, it allows for more diverse applications.


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.


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.


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.


Quadrilaterals have two main characteristics:

1. They are CLOSED entities,

2. They have 4 sides.


Polygon means “many sided”:

Most polygons have names based on the number of sides they have.


2D and 3D Space:

Let’s take a few minutes to see how lines and points are used to organize space…..


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.


However, as the universe is not 2-dimensional, we must take into consideration a 3rd axis (Z) that represents its volume.


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.


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)

Standard Sheet Sizes


Next Week:

Sketching, Text, and Visualization

Documents

TECH 104 – Technical Graphics Communication Introduction to Engineering Graphics Communication