Topic 3 Engineering Sketching
(detailed objectives) (available resources)
Goal: Students learn to convey their technical ideas with technical sketches.
[standards: NM-MEA.6-12.2]
Curriculum for our EST Pipeline
(to review the detailed content, download the low resolution pdf of available teacher presentation)
Without the ability to communicate well, engineers cannot function in a team and are of limited value to industry.  Technical drawing and sketching are essential communication tools for engineers.  Using established sketching conventions (orthographic projections and isometric sketches), students will learn how to quickly convey their design ideas to others.

The ability to sketch ideas is not only important to engineers it is absolutely essential.  Even if an engineer was stranded alone on an island, the ability to sketch would help to work out details in ideas and help to identify potential problems.  Technical sketching and drawing does NOT require any artistic ability.  Once one is made aware of the basic techniques, it is no longer the "ability to draw" that will limit his/her sketches.  But rather, the limitation is one's "ability to think through the details of their design."  In industry sketching is used to quickly document rough ideas and identify general needs for improvement.  Technical drawing would be employed only for those ideas deserving a permanent record.  Sketches and drawings are composed of the same basic information, but there is a tradeoff between time required to generate it verses the level of design detail (and accuracy).  The basics of technical sketching can be learned in a single sitting.  However, it will take considerable practice to achieve the fluency that really facilitates team discussions in the future.  Don't be surprised if those who are new to sketching actually enjoy working on sketching assignments.  It is an easy area for most students to achieve in.

Orthographic Projection is a generally accepted convention for representing 3D objects using multiple 2D views of the front, top, bottom, back, and sides of the object.  In practice, the minimal number of views possible is used to describe all the details of the object.  Usually, the Front View, Top View, and a single Side View are sufficient and are oriented on the paper according to accepted convention.  Isometric Projection attempts to represent 3D objects using a single view.  Instead of the observer viewing the object perpendicular to the object, the object is rotated both horizontally and vertically relative to the observer.
orthographic and isometric projections

There are rules and conventions to guide the creation of both types of projections.  Additionally, either of them can be supplemented with various types of dimensions.  Whether sketching or drawing, the goal is the same.  The goal is to communicate the necessary detail to the intended audience.

Teacher Preparation
  1. Gather some simple objects that have varying features on each side (like video casette tapes, stapler, etc.) and produce reasonably accurate orthographic projections for at least one of the objects.
  2. Prepare isometric sketches of objects composed of basic shapes (rectangles and circles) that will be used to practice orthographic projection sketching.
  3. Prepare isometric and orthographic graphing paper appropriately scaled for the objects that you have chosen.
  4. Prepare examples of basic dimensioning practices.
Classroom Activities
Without any introduction to technical sketching guidelines, have the students sketch one of your selected objects "with enough detail that someone else can make a similar object."  Compare their sketches to a detailed technical sketch (that describes features on every side, has basic dimensions, and includes basic material descriptions).  Explain the basic rules of orthographic sketching using a few examples.  Then allow the students to practice in small groups.  Explain the basic rules of isometric sketching using a few examples.  Then allow the students to practice in small groups.  Allow the students to work together to answer questions about a real part based on dimensioned sketches (or drawings) of the part.  If you wrap up the week by having the students re-sketch the object from the beginning of the week, there should be some very obvious improvements.

3.1 Orthographic Projection Sketching
  • Comprehend the role that sketching/drawing play in communication in a team environment
  • Comprehend the role that sketching plays in the creative process
  • Comprehend similarities and differences between sketching and drawing
  • Know the sketching guidelines
  • Comprehend the orthographic projection page layout
  • Know various linetypes on sketches and drawings

Students demonstrate ability to describe real objects using sketching skills.
Engage students with teacher presentation.
3.2 Practice Orthographic Projection Sketching
  • Apply sketching and projection rules to create 2D sketches that describe 3D objects

Engage students with teacher example of sketching.
Individually practice orthographic projection sketching.
3.3  Isometric Sketching
  • Comprehend how to use grid paper in sketching
  • Know the difference between isometric and orthographic projection sketches

Students discuss the implications of grid lines on grid paper.
Engage students with teacher example of sketching.
3.4 Practice Isometric Sketching
  • Apply knowledge to create isometric sketches from orthographic projections

Individually practice isometric sketching.
3.5 Dimensioning
  • Comprehend basic rules of dimensioning
  • Evaluate effectiveness of existing dimensions at communicating a part's features
  • Apply knowledge to interpret dimensions and notes from a complex drawing

Students read through information about dimensioning.
Engage students with teacher presentation.
Work in small groups to answer questions based on the handout.
Additional resources available to licensed users:
In addition to 27 animated PowerPoint customizable slides...
Student Resources
3-handout-example dimensions.doc
3-graph paper generator

suggested reading handout

Supplemental reading materials (printable or web linked)
Practice and Assessment Templates
3-practice sketching.doc
3-practice projection.doc
3-practice sketching2.doc
3-practice isometric.doc
3-practice isometricKEY.doc
Template for Practice Assignments
3-practice specialties.doc

Template for assessing learning objectives
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