March 5, 2010 2-24 1. Quiz Monday on the following: IOT POLY ENGINEERING 2-24 March 5, 2010 1. Quiz Monday on the following: Describe the differences between isometric, perspective, and oblique drawings On diagonal grid paper, draw an isometric based on given orthographic projections Find the starting point for orthographic projections and isometric drafting

Review OBLIQUE 2-10 3 A way of showing depth, like isometric IOT POLY ENGINEERING 2-10 Review OBLIQUE 3 A way of showing depth, like isometric Part orthographic / part isometric: One face is true form Parallel lines behind; either: Full scale Half scale Three-quarter scale TYPE 3: PICTORIAL

Review PERSPECTIVE 2-10 3 TYPE 3: PICTORIAL IOT POLY ENGINEERING 2-10 Review PERSPECTIVE 3 Latin: perspicere – to see through An approximate representation of an image as it is perceived by the eye. The most characteristic feature of perspectives is that objects are drawn: Smaller as their distance from the observer increases TYPE 3: PICTORIAL http://www.ider.herts.ac.uk/school/courseware/graphics/one_point_perspective.html

Review ISOMETRIC 2-10 3 TYPE 3: PICTORIAL From Greek: Equal Measure IOT POLY ENGINEERING 2-10 Review ISOMETRIC 3 From Greek: Equal Measure Isos: Equal Metron: Measure The scale along each axis of the projection is the same True form parallel lines are shown as parallel (note colors below) All isometrics: simple construction TYPE 3: PICTORIAL Isometric Cube: 1) all lines equal length; 2) all faces equal area; 3) perimeter is a hexagon

QUIZ REVIEW 2-24 Isometrics: Perspectives: Obliques: IOT POLY ENGINEERING 2-24 QUIZ REVIEW Isometrics: Parallel projection True size (you can measure the lengths accurately) Perspectives: Shown as it is perceived by the eye Object gets smaller the farther away it is Obliques: One face is orthographic projection The rest of object is parallel projection

Quiz drawing will be an altered version of one of your homeworks: QUIZ REVIEW On diagonal grid paper, draw an isometric based on given orthographic projections Quiz drawing will be an altered version of one of your homeworks:

HORIZONTAL STARTING POINT 1. Add width of front view to width of right view. 4.5” + 2” = 6.5” 2. Add the space we will put between: 1.5” 6.5” + 1.5” = 8” 3. Subtract from the total width. 10” – 8” = 2” 4. Divide by 2. Horizontal Starting Point = 1”

VERTICAL STARTING POINT 1. Add height of front view to height of top view. 3” + 2” = 5” 2. Add the space we will put between: 1.5” 5” + 1.5” = 6.5” 3. Subtract from the total height. 7.25” – 6.5” = .75” = 3/4” 4. Divide by 2. Vertical Starting Point = .375” = 3/8”

DRAFTING ISOMETRIC DRAWINGS IOT POLY ENGINEERING 2-21 DRAFTING ISOMETRIC DRAWINGS Describe an isometric view Height Width Depth (of the front view) Technical Graphic Communication

DRAFTING ISOMETRIC DRAWINGS Prepare drawing paper Locate center of drawing space Construction Lines Technical Graphic Communication 45 degree triangle

DRAFTING ISOMETRIC DRAWINGS Plot starting point of drawing 1) ½ W 2) ½ D 3) ½ H Technical Graphic Communication 30-60-90 triangle Starting Point

DRAFTING ISOMETRIC DRAWINGS IOT POLY ENGINEERING 2-21 DRAFTING ISOMETRIC DRAWINGS Complete isometric drawing Technical Graphic Communication Starting Point

SOLUTIONS

CLASSWORK – Drafting Isometrics 3 March 10 IOT POLY ENGINEERING 2-21 CLASSWORK – Drafting Isometrics Draft the following isometrics on drawing paper (use dimensions previously given for left drawing): 2” 2” 1” 1” 1” 4”

Introduction to AutoCAD IOT POLY ENGINEERING 2-24 Introduction to AutoCAD AutoCAD is a communication technology tool: Creating neat, accurate drawings and designs. There are numerous features – we will concentrate on the most important ones. Technical Graphic Communication One of the most important actions within the AutoCAD program is the drawing of straight lines. http://en.wikipedia.org/wiki/Image:World_population.svg Before we learn the LINE command, let’s take a look at how we normally draw lines by hand.

Absolute Coordinates AutoCAD 0 1 2 3 4 5 6 7 8 9 10 Plot lines: 0 1 2 3 4 5 6 7 8 9 10 Plot lines: FROM: TO: 1,1 1,5 1,5 4,9 4,9 7,5 7,5 7,1 1,5 7,5 3,1 3,4 3,4 5,4 5,4 5,1 0,1 10,1 AutoCAD

Absolute Coordinates 2-3 IOT POLY ENGINEERING 2-3 Absolute Coordinates Absolute coordinates are based on the origin (0,0), expressed as an ordered pair x,y. All other points are also expressed in the form x,y and the values of x and y are based on the distance from the origin. If we desire to draw a line, we must give the location of both endpoints, expressed as an ordered pair x,y where the origin is used as a reference point. http://en.wikipedia.org/wiki/Image:World_population.svg

Relative Coordinates AutoCAD 0 1 2 3 4 5 6 7 8 9 10 Plot lines: FROM: 0,1 0 1 2 3 4 5 6 7 8 9 10 @ 10,0 FROM: 1,1 @0,4 FROM: 0,5 @10,0 @5,2 @5,-2 FROM: 9,5 @0,-4 AutoCAD

What is the distance between the two orange lines? Relative Coordinates What is the distance between the two orange lines? 0 1 2 3 4 5 6 7 8 9 10 Offset distance = .5 Plot lines: FROM: 3,1 @0,2 @1,0 @0,-2 FROM: 5,1 @0,3 @3,0 @0,-3 AutoCAD

Communication Technology Introduction to AutoCAD IOT POLY ENGINEERING 2-24 Communication Technology Introduction to AutoCAD Relative coordinates are not based on the origin (0,0). Instead, we use the @ symbol followed by an ordered pair x,y. This means “starting where we are AT, go over (or back) x and up (or down) y. If we desire to draw a line using relative coordinates, we must give the location of the first endpoint (usually using Absolute coordinates), followed by @x,y for the second endpoint. http://en.wikipedia.org/wiki/Image:World_population.svg

Relative Coordinates AutoCAD 2-24 IOT POLY ENGINEERING 2-24 Relative Coordinates In AutoCAD, you do not have to specify the start point with coordinates – you can just click anywhere. AutoCAD

Absolute and Relative Coordinates IOT POLY ENGINEERING 2-24 Absolute and Relative Coordinates On the graph paper provided, draw coordinate axes about half the size of your graph paper. Draw an object with at least 10 lines. The end points must land on intersections of graph paper lines. Tear a blank sheet of notebook paper in half. On one half, write out the absolute coordinates required to draw the object. On the other half, write out the relative coordinates required to draw the object. Someone else will be drawing your object based on the coordinates you create. http://en.wikipedia.org/wiki/Image:World_population.svg FROM: TO: 1,1 1,5 FROM: 0,5 @5,2 @5,-2

IOT POLY ENGINEERING 2-24 Homework Trade absolute coordinates with someone in class. Put his/her name on a blank area of your graph paper, write the word “absolute,” and draw the object based on the coordinates. Trade relative coordinates with someone in class. Put his/her name on a blank area of your graph paper, write the word “absolute,” and draw the object based on the coordinates. Bring back your partner’s coordinate sheets tomorrow.