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2D EssentialsInstructor: Laura Gerold, PECatalog #10614113Class # 22784, 24113, 24136, & 24138Class Start: January 18, 2012 Class End: May 16, 2012
Questions . . .
When you are working on plans that will be used in Europe or Asia.
When do you include the projection angle symbol on plans?
ELLIPSE TEMPLATES
These ellipse guides are usually designated by the ellipse angle, the angle at which a circle is viewed to appear as an ellipse.
DRAWING A FOCI ELLIPSE Major axis = long axis of ellipse Minor axis = short axis of ellipse The foci of the ellipse are two special points E
and F on the ellipse's major axis and are equidistant from the center point. The sum of the distances from any point P on the ellipse to those two foci is constant and equal to the major axis ( PE + PF2= 2A ). Each of these two points is called a focus of the ellipse.
DRAWING A FOCI ELLIPSE Let AB be the major axis and CD the minor axis To find foci E and F, draw arcs R with radius equal to half
the major axis and centers at the end of the minor axis Between E and O on the major axis, mark at random a
number of points. Using a random point (point 3), with E and F as centers
and radii A-3 and B-3, draw arcs to intersect at four points 3’. Use the remaining points to find four additional points on the ellipse in the same manner.
Sketch the ellipse lightly through the points
Drawing an Ellipse
Draw a major axis 5” long and a minor axis 2.5” long. Draw an ellipse by the foci method with at least five points in each quadrant
DRAWING AN ARC TANGENT TO TWO LINES AT ACUTE OROBTUSE ANGLES Given two lines not making a 90° Draw lines parallel to the given lines at distance R from
them to intersect at C the center From C, drop perpendiculars to the given lines to locate
tangent points, T With C as the center and with given radius R, draw the
required tangent arc between the points of tangency
DRAWING AN ARC TANGENT TO TWO LINES AT ACUTE OROBTUSE ANGLES
Draw two intersecting lines at an acute angle, each 2.5 inches long
Draw a 1.5 inch radius arc tangent to the two lines
{TEST REVIEW
50You have the entire class period to complete the test
How Many Questions are on the Test?
True and False Multiple Choice Fill in the Blank Essay Questions Drawing
How are the questions formatted?
All of your drawing utensils A Calculator
This is NOT an open book exam. Other electronic devices can not be
used in place of a calculator
What can I bring?
Circles Squares Bisect an angle Perpendicular Bisect a line Triangles Orthographic Sketches Alphabet of Lines Lettering
What do I need to know how to draw?
Chapter 1 Chapter 2 Chapter 3 (Sections 1-5) Chapter 4 Chapter 5
What Chapters in the Book Will be Covered?
Class Notes (Power Points on Blackboard)
Class Notes you took Homework Textbook
What Should I Use to Study?
Identify and Describe the five phases of the design process
Identify what technical drawings are used for Identify why drawing by hand is still useful Identify who creates technical drawings and
what professions use them Draw & Identify the Alphabet of Lines
Potential Topics on Test
Apply civil engineering scales to sketches of simple objects
Apply architectural scales to sketches of simple objects
Scale a drawing up or down using scale ratios (ex 1:2, 2:1)
Apply standard lettering practice and standards to sketches
Identify negative space
Potential Topics on Test
Describe Prisms Describe Cylinders Describe Pyramids Describe Cones Describe Spheres Describe a Torus Describe Ellipsoids
Potential Topics on Test
Describe Parallelograms Describe a Trapezoid Describe a Trapezium Describe a Regular Polygon up to 8 Sides Describe a Circumference of a Circle Describe Diameter of a Circle Describe Radius of a Circle Describe a Quadrant of a Circle Describe a Chord of a Circle Describe Concentric Circles Describe Eccentric Circles Identify the point at which a line is tangent to an arc Identify the pint at which an arc is tangent to an arc
Potential Topics on Test
Differentiate between the 1st and 3rd Angle Projection
Name and position the 6 primary views Create orthographic sketches of simple
objects Transfer dimensions Apply hidden line conventions to sketches Apply line precedence conventions to
sketches
Potential Topics on Test
Write down a question that you still have about a topic that will be covered on the test.
Share the question and topic with your group
As a group determine the answer to the question
Still stumped? Ask a neighboring group Classroom stumped? Save the question for
the end and ask me
What are you confused about?
It’s time for a review game!
Stand up and Stretch . . .
Which Team Will Dominate? Winning team will each receive 5 extra credit points.
Pick a team name Team members pick a category and answer the next
question in that category All question are answered in order starting with 1 then
2, etc. If the team answers correctly, they get 2 points If they have to use their text to answer, they only get 1
point If nobody on the team is able to answer the question
correctly, they can say “pass.” The next team gets a chance to answer for 1 point.
Information Domination
Design Process 1, 2, 3, 4, 5 Alphabet of Lines 1, 2, 3, 4, 5, 6 Scales 1, 2, 3, 4, 5 Lettering 1, 2, 3, 4 Solids 1, 2, 3, 4, 5, 6, 7, 8 Planar Shapes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Orthographic Sketches 1, 2, 3, 4, 5, 6, 7, 8
Information Domination
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Ready for the Test??
Any additional questions??
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Chapter 5 – ORTHOGRAPHIC PROJECTION
VIEWS OF SURFACESThere are terms used for describing a surface’s orientation to the plane of projection. The three orientations that a plane surface can have to the plane of projection are normal, inclined, and oblique.
Note how a plane surface that is perpendicular to a plane of projectionappears on edge as a straight line
Wisconsin House Hotel – Normal Surfaces
A normal surface is parallel to the plane of projection
It appears its true shape and size on orthographic drawings.
A edges are true length on plane of projection
Normal Surfaces
Use your blocks to make a creation different than last week
Sketch the three necessary views
“Normal” Group Project
Heritage Hill – Inclined Surfaces
An inclined surface is perpendicular to one plane of projection
It is inclined or tipped to adjacent planes Inclined edge is parallel to one plane of projection
and appears true length on this plan (appears as angled line)
Inclined edge appears as a foreshortened line on adjacent planes (appears as horizontal or vertical line)
Inclined Surfaces
Each group gets a right triangular prism
Draw the three necessary views
What was different about drawing the inclined planes versus the normal planes (with the blocks)?
“Inclined” Group Project
Milwaukee Art Museum – Oblique
Surfaces
An oblique surface is tipped on all principal planes of projections
It does not appear on edge or true size in any standard view
An oblique edge appears foreshortened and at an angle in every view
Oblique Surfaces
As a group, try to think of any oblique surfaces you have seen at home, work, or on your way here tonight.
Sketch up a few and present to class
“Oblique” Group Project
ANGLES
If an angle is in a normal plane (a plane parallel to a plane of projection) it will show true size on the plane of projection to which it is parallel.
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Chapter 6 – 2D Drawing Representation
Conventional Representations
Standard orthographic projections don’t always show complex shapes as clearly and simply as you may wish, so certain alternative practices, referred to as conventions, are accepted.
Conventions are like rules for breaking the rules. Note how these views are projected
Orthographic Views of Intersecting and Tangent Surfaces. (Lockhart, Shawna D.; Johnson, Cindy M., Engineering Design Communication: Conveying DesignThrough Graphics, 1st, © 2000. Printed and Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.)
What do you notice on these drawings?
Can’t always show all views on a sheet
When this is the case, use a removed view
Two ways to show this. . .
Removed Views
Removed Views – Type 1
Use a View Indicator arrow to show direction of sight
Removed Views – Type 2
Use a Viewing Plane Line
Remove a View from one of your group drawings of today
Create a removed view plane using an indicator arrow or viewing plane line
Group Project – Removed Views
Manufactured Features
• Fillet
• Round
• Counterbore
• Countersink
• Spotface
• Boss
• Lug
• Flange
• Chamfer
• Neck
• Keyway/Keyseat
• Knurl
• Bushing
For class on March 21st, bring in objects with “manufactured features” for use in group projects
Manufactured Features
Overview of Drafting
Review of Drafting
What’s Next?
• Test next week – March 7th
• Spring Break March 14th - NO CLASS• Finish Chapter 6 – 2D Drawing
Representation on March 21st
Questions?
On one of your sketches, answer the following two questions: What was the most useful thing that
you learned today? What do you still have questions
about?
Homework – Due March 21st!
Chapter 5 Review Question: 5Chapter 5 Exercises: 5.2, 5.5 (9), 5.6 (8– no isometric drawing)