Engineering Sketching Techniques
“A picture says a thousand words”
Allyson White
STEM Lab 2011
THE DESIGN PROCESS
Define
Goals
Generate
Ideas
Plan
Improve
Test
Build
Learning Goals
Recognize the three basic styles of
engineering sketches.
 Understand why a detailed sketch is a
powerful communication tool.
 Be able to accurately sketch an object
using isometric, orthographic, and oblique
design methods.

Why?

Troubleshooting:
◦ Sketches allow engineers to see each part of a
product before a prototype is developed

Communication:
◦ Sketches reveal details of a product; size
shape, and features, quickly and accurately.
5 Minutes to Prove It!

This activity will illustrate how much better a
sketch communicates an idea than a verbal
description.
1. Draw a large rectangle on your paper.
2. Draw 2 smaller rectangles inside the large
rectangle.
3. Draw a circle inside one of the small rectangles.
4. Compare your design to your neighbors.
Are all the designs the same?
Does your design match mine?
Isometric Projection

Isometric projections show three sides of
an item in proportional dimensions.
◦ All vertical lines are vertical
◦ All horizontal lines are drawn at a 30° angle.
Picture Source: Total Fabrication, Retrieved from:
http://tle.tafevc.com.au/toolbox/items/2915349d-458b-d355-6733a2388c8eb190/1/905_draw_t3.zip/2_draw/draw_t3/htm/draw3_2_2.htm
Isometric Projection- Dimensions
Clearly label important dimensions.
Label contains numbers only
Unit of measurement is located bottom of design
Do not label more than is necessary to build the item.
Illustration created with Google SketchUp 6®
Orthographic Projection
Orthographic sketches represent 3D
items in multiple 2D drawings.
 Top, front, bottom, and side views may be
used.
 The general rule is to use only the views
necessary to show the details of the item.

The Glass Box

Imagining your item in a glass box is a
good way to mentally separate the faces
of the item before beginning an
orthographic sketch.
Image source: Martin (n.d.)
https://mail.nvnet.org/~martins/TAD1/linx/ortho.html
Orthographic Example
Top
Side left
The edges of each view line up as though
“the box” had been unfolded.
Illustration created with Google SketchUp 6®
Oblique Projection
Oblique projections are
1.
perhaps the simplest of the
3D sketch techniques.
1. Sketch the front of the
item.
2. Project lines back from the
vertices at 45° angles.
These lines are drawn at
one-half scale.
3. Connect the lines to form
the visible portion of the
back of the item.

Computer Aided Design (CAD)

Software packages
range from the
simple such as the
ModelSmart program
we use, Google
SketchUp (free to
download) to the
very complex.
Manual Design

There are many
specialized tools for
manually creating
technical designs.
◦
◦
◦
◦
◦
◦
◦
◦
45°/90° triangle
30°/60° triangle
Protractor
Square
Ruler
Compass
Specialized grid paper
And many more...
Independent Practice
Choose a common object that is easily
identified.
 Create 3 projections of the object.

◦ Isometric
◦ Orthographic
◦ Oblique
Use the classroom drafting tools.
 Use the specialized grid paper.

Drafting tools may be signed out during pm homeroom
and must be returned during the next morning’s am homeroom
Resources for Students

Sokolowski, G. (2004) Orthographic Projection #1,
Wisc-Online.
http://www.wisc-online.com/objects/ViewObject.aspx?ID=ENG19204

Ryan,V. (2011) Oblique projections:
http://www.technologystudent.com/despro2/obli1.htm

Ryan,V. (2011) Isometric projections:
http://www.technologystudent.com/prddes1/drawtec2.html
Standards Alignment

Standard 11: Students will develop abilities to
apply the design process.
◦ [H] Apply a design process to solve problems in and
beyond the laboratory-classroom.
◦ [J] Make two-dimensional and three-dimensional
representations of the designed solution.

Standard 17: Students will develop an
understanding of and be able to select and use
information and communication technologies.
◦ [K] The use of symbols, measurements, and drawings promotes
clear communication by providing a common language to express
ideas.
Resources

EST Foundations (2006), Topic 3- Engineering Sketching. Retrieved from:
http://www.estfoundations.com/index.html

Google Inc., (2007) Google SketchUp Version 6.4.112. Retrieved from:
http://sketchup.google.com/

Martin Suzette (n.d.) Technical and architectural design one, Orthographic
projection. Retrieved from:
https://mail.nvnet.org/~martins/TAD1/linx/ortho.html

Ryan,V. (2011) Isometric projections: technologystudent.com. Retrieved
from: http://www.technologystudent.com/prddes1/drawtec2.html

Ryan,V. (2011) Oblique projections:, technologystudent.com. Retrieved
from: http://www.technologystudent.com/despro2/obli1.htm

Sokolowski, G. (2004) Orthographic Projection #1, Wisc-Online. Retrieved
from: http://www.wisc-online.com/objects/ViewObject.aspx?ID=ENG19204

Total Fabrication, (n.d.) What is isometric drawing?. Retrieved from:
http://tle.tafevc.com.au/toolbox/items/2915349d-458b-d355-6733a2388c8eb190/1/905_draw_t3.zip/2_draw/draw_t3/htm/draw3_2_2.htm