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1
First-Year Engineering Program
AU 2006
Engineering H191Engineering Fundamentals and Laboratory I
Week 01 Day 01
Graphics: The Language of Design
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First-Year Engineering Program
AU 2006
Objectives
• Understanding graphics as a communication tool• Technical sketching• Projections
– Orthographic– Pictorial
• Sketching hints• Lettering
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First-Year Engineering Program
AU 2006
How Would You Describe This?
• In teams of two, describe using only words• How effective is this approach?
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First-Year Engineering Program
AU 2006
• Freehand sketches
• Instrument drawings
• Computer drawings and models
Three Basic Types of Technical Drawings
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First-Year Engineering Program
AU 2006
Introduction to Projections
• Present 3-D objects with 2-D media• Two Basic Categories
Orthographic Pictorial
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First-Year Engineering Program
AU 2006
Projections: Four Basic Types
Orthographic Projections
Axonometric
Oblique Perspective
Pictorials
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First-Year Engineering Program
AU 2006
Orthographic Projections
• Collection of 2D drawings• Accurately represent object
• Technical Graphics - Chapter 3
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First-Year Engineering Program
AU 2006
Which Views to Present?
• General Guidelines
– Pick a Front View that is most descriptive of object
– Normally the longest dimension is chosen as the width (or depth)
– Most common combination of views is to use: Front, Top, and Side View
– Views other than the Principal Views are called Auxiliary Views (see 3.15 in the Technical Graphics text)
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First-Year Engineering Program
AU 2006
Conventional Orthographic Views
Height
Depth
Width
Front View
Top View
Right Side View
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First-Year Engineering Program
AU 2006
• Hidden Lines – represent features that cannot be seen in the current view
• Centerlines – represent symmetry and mark the center of circles, the axes of cylinders, and the axes of symmetrical parts, such as bolts
Hidden and Center Lines in Orthographic Projections
• Object Lines – represent visible features for an object
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First-Year Engineering Program
AU 2006
• Front View• Right Side
View• Top View
Creating the Orthographic Projection Sketch
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First-Year Engineering Program
AU 2006
Step 1 – Lightly Block Three Views
Use very light lines for drawing in
the construction
lines
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First-Year Engineering Program
AU 2006
Step 2 – Lightly Block Major Features
Use very light lines for
drawing in the construction
lines
• Holes• Arcs• Cutouts
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First-Year Engineering Program
AU 2006
Step 3 – Refine and Locate Features in All Views
Use very light lines for drawing in
the construction
lines
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First-Year Engineering Program
AU 2006
Step 4 – Add Final Lines
Use very light lines for drawing in
the construction
lines
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First-Year Engineering Program
AU 2006
Add Another View
• Sketch the left side view of the object• Compare your view with the others at your table
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First-Year Engineering Program
AU 2006
Lettering Notes
• Lettering Guidelines – Technical Graphics: Chapter 1
• Lettering Styles– Shape of Letters– Order of drawing lines
• Character Uniformity• Spacing
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First-Year Engineering Program
AU 2006
Sketching Tips: General
• Relax and draw in a direction comfortable to you• Mark end points of the lines to be sketched and
draw between them• Draw long lines as a series of short ones• Use grid paper when available• Follow sketching and text conventions
• Do NOT use a straight edge to draw lines!
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First-Year Engineering Program
AU 2006
Sketching Tips: Construction Lines
• Use construction lines• Begin by drawing bounding boxes with
construction lines• Make construction lines much lighter and thinner
than finished lines• Identify the major features and overall
dimensions• Leave construction lines on the sketch
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First-Year Engineering Program
AU 2006
Sketching Tips: Miscellaneous
• Do not shade the drawing – this is not pencil sketching
• Title information is required• Keep views aligned (very important)• Include centerlines on isometrics• Avoid labels on the sketch• Draw neat circles – change page orientation if
needed