Lesson: Intermediate Drawing & Drafting

Authors: Ann Cunningham, David Nietfeld, Peter Anderson 

Class Size 

  • This lesson was designed to be taught to 30 students, divided into 5 groups of 6. The groups would rotate between 5 stations. 

Lesson Structure  

150 minutes 

  • Introduction: 10 minutes 
  • Rotation 1: 24 minutes + 4 minutes for rotation 
  • Rotation 2: 24 minutes + 4 minutes for rotation 
  • Rotation 3: 24 minutes + 4 minutes for rotation 
  • Rotation 4: 24 minutes + 4 minutes for rotation 
  • Rotation 5: 24 minutes  
  • Wrap up: 4 minutes 

Objectives 

In this lesson, students learn skills (e.g., accurate nonvisual measuring and conventions for representing various perspectives) that are essential for developing technical drawings like those used in engineering.  

Students will: 

  • Learn some of the components that comprise pictures (pictures defined as a representation of a 3D object on a 2D plane). Students will learn about foreground, middle, and background, on and off the picture plane. They will experiment with picture composition by rearranging shapes they cut out and deconstruct complex objects to understand how to create a 2D representation. 
  • Be able to explain what the picture plane is and demonstrate which objects in a scene are on the picture plane and which are extending off the picture plane. 
  • Develop skills in using nonvisual tools (tactile protractor, Braille calipers, Sensational Drafting Board, notched 30º/60º/90º triangle) needed to create accurate technical drawings. 
  • Develop and refine nonvisual techniques needed to create accurate technical drawings including: 
    • Measuring lines, angles, and the diameter of a circle 
    • Drawing lines of a desired length, angles of a desired size, and circles of a desired diameter 
    • Connecting lines to create desired shapes 
  • Be able to draw an isometric cube with verbal directions. 

Prerequisite Knowledge and Skills 

  • Skills and concepts covered in Introduction to Drawing including: 
    • How to find the outline of simple shapes 
    • Introduction to how to read and draw an elevation 
  • How to use a glue stick 

Accessibility 

  • Sensational BlackBoard (SBB) 
  • Sensational Drafting Board (SDB) 
  • Braille ruler 
  • Braille protractor 
  • Braille calipers  
  • Notched 30º/60º/90º triangle 
  • Workbook available in Braille/tactile, large print, accessible digital formats 
  • Print/Braille alphabet stickers 

Materials 

Materials needed per student at each station (unless otherwise stated): 

Note: Refer to Accessible Lab Equipment & Instructional Materials for additional information regarding specialized tools/materials. 

Preparation 

  1. Create materials: 
    • 2” x 3” block and triangular block for roof 
    • 3” cube mounted 6” above a base on a sturdy dowel 
    • Picture plane manipulative 
    • 3 basic wooden doghouse models 
    • Multiview chipboard templates to match doghouse models 
  2. If you are working with a large class, each activity can be setup at its own table, and students can rotate through the stations throughout the lesson. A smaller class may work sequentially through each station together. 
  3. Picture analysis: Separate the 5 correct images and the 10 images with one mistake and the 5 images with 2 mistakes into separate piles for each student. Make sure the separate piles are not in the same order for all the students. 

Note: Refer to Materials that Require Plans for additional instructions on creating specified materials. 

Procedure 

Introduction 

  1. Domains of drawing and drafting. 
    • Tell. “In this session you will learn skills associated with five domains of drawing and drafting, knowledge you will utilize throughout the unit to complete your project. You will learn about these domains by cycling through a series of five stations.” Each station is focused on one of the domains: 
      • Measuring: You’ll learn how to accurately measure the length of a line and the size of an angle. You will also learn how to draw and position lines and circles of precise sizes. 
      • Composition and labeling: You will learn how to compose a picture to communicate information and how to add Braille and print labels to provide additional information. 
      • Isometric perspective: You will learn about isometric perspective, which is what we call the technique used to represent 3-dimensional objecting in a 2-dimensional space and draw an isometric projection of a cube. 
      • Picture analysis: You will learn how to look at a real object and determine what point of perception the picture is illustrated from and if it is accurate or not.  
      • Picture plane: You will learn what a picture plane is, how it functions, and some of the conventions used in orthographic projections. 
  2. Describing activity. 
    • Tell. “We will rotate around the stations in 24-minute sessions with a few minutes to rotate to the next station.” 
    • Do. Break students up into five groups. 

Station 1: Measuring 

  1. Orientation to the station. 
    • Tell. “In front of you is a Sensational Blackboard. From left to right, above your board you will find a pen, a Braille ruler, a Braille calipers, a compass, and a Braille protractor. These are the tools we will use for the worksheets at this station. To label your work, there are slates and styli and glue sticks for Braille readers and 20/20 markers for print readers.”  

Page 1 

  1. Measure using Braille calipers. 
    • Tell. “In your workbook I'd like you to find page 1 in the measurement section of your workbook. There are three pages for this unit. Put page 1 on the Sensational Blackboard so that the page number is in the lower right-hand corner. In the middle of the page, find the two horizontal lines of different lengths. I want you to use the tools that are at your workstation to measure the length of each line. We have the choice of two tools to measure the length. We have a Braille ruler, and we have Braille calipers. I want to show you how the calipers work. Even if you don’t read Braille, it might be worth learning a few dot patterns so that you can use this tool. It is very useful and accurate. Let’s measure the line on the top together. We will use the calipers.”  
    • Tell. “Open the caliper arms so that they extend beyond the ends of the line. Find the right end of the line and place your pen at that spot and hold it perpendicular to the page. Cozy the right caliper arm up to your pen. Once you have that in position, I want you to secure the calipers with your right hand.” 
    • Tell. “Now scan with your left hand to find the other end of the line. Place the pen at the left end of your line and then cozy up the left caliper arm up to your pen. You should now have the caliper arms positioned at each end of your line. You can then go to the caliper readout and see how long this line is. At this point you can move the calipers but be careful not to move the caliper arms, as that will change the measurement. Read the inches on the caliper ruler first and then read the fraction on the caliper arm. The measurements are reported in 16ths of an inch. You will want to reduce the fraction to its lowest terms. If you had the measurement 8/16ths what would the lowest terms be?” [½] 
  2. Measure using a ruler. 
    • Tell. “Can someone explain how to use a traditional ruler?” 
    • Do. Solicit answers. 
    • Tell. “Along the straightedge you will notice lots of perpendicular lines of a few different lengths. Each inch is marked with the longest line, ½ inch increments are marked with the second longest line, ¼ inch increments are marked with the third longest, and ⅛ inch increments are marked with the shortest tactile line. Visually there is also an even shorter line to indicate a 1/16”.” 
  3. Finish measuring and label.  
    • Tell. “Use either the calipers or the ruler to measure the second line. Once you have measured your lines, I would like you to label each line with its length. There are three methods you can use to label these lines: a 20/20 marker, a slate and stylus, or a plastic print/Braille alphabet sticker and an associated key on a separate sheet of paper.” 

Page 2 

  1. Using a protractor. 
    • Tell. “Now we’re going to learn how to use the protractor. Find your tactile protractor. Can someone who is familiar with this tool explain how to use it to measure angles? The tool is half a circle with a long pointer attached to the center of the baseline. The half circle is marked with notches every 5º. The base line is 0º at one end and 180º at the other. There are three points between 0º and 180º that are marked with three dots: 45º, 90º, 135º. This protractor utilizes vertical opposite angles. When two lines intersect, the angles opposite one another are congruent. So, with this tool, you line the base and the pointer up with the angle on your paper and the protractor creates the vertical opposite angle on the half circle, which gives you the measurement.” 
  2. Set up protractor. 
    • Tell. “Find page 2 in the measurement section of your workbook. The drawing on this page is of four different angles. Place the baseline of the protractor parallel to one of the two lines making the angle you want to measure. Make sure the plastic half circle of the protractor does not cover the angle you are measuring.” 
  3. Adjust the protractor. 
    • Tell. “Place your pen at the vertex of the angle you want to measure. Slide the bottom of the protractor so that the pointer is near the vertex and near your pen. Keeping the base line aligned to the angle, swing the tail end of the pointer to run parallel to the other leg of your angle. Once you have both legs of your angle parallel to both arms of your protractor, you are in the right position. Tighten the set screw.” 
  4. Read the measurement. 
    • Tell. “Next move up from the tail end of the pointer to the point and read the degrees of your angle on the protractors edge where it is marked with notches and dots. The notches mark 5 degrees. The three dots mark 45º, 90º, and 135º.” 
  5. Finish measuring and label. 
    • Tell. “Go ahead and measure the four angles on page 2 and label them.” 

Page 3  

  1. Using a compass. 
    • Tell. “Finally, I would like you to measure the diameter of the two circles on page 3. We will use the compass for this task. Find the two quick release levers on the compass legs. If you depress these, you can move the legs easily in either direction. Place the leg with the sharp point in the middle of the top left circle on your page. Move the other leg so that it is close to the outside line. You can now use the wheel to fine tune the distance of the legs so that it is right on the outside line describing the circle. You can now measure the length of that line with the ruler or the calipers. Once you have that measurement, you will double it for the diameter of the circle.” 
  2. Finish measuring and label. 
    • Tell. “Go ahead and measure and label the circles.”    

Blank pages 

  1. Drawing objects 
    • Tell “Take a blank piece of paper, and use your measuring skills to draw each of the following.” 
      • A 4.5 inch long line 
      • A 5.73 inch long line 
      • A 2 inch diameter circle 
  2. Drawing angles 
    • Tell. “Take another sheet of blank paper, and use your protractor to draw a triangle with angles of 30 degrees, 60 degrees, and 90 degrees. 

Station 2: Composition and Labeling 

  1. Introduction to composition. 
    • Tell. “Composition is the act of arranging elements of an image by paying attention to how they relate to each other. At this station you will learn how to break a fairly complex object down into its component parts. We will select simple shapes cut out of textured papers and then rearrange them on another piece of paper to represent the desired 3D object on a 2D plane. This technique gives us the opportunity to arrange and rearrange the pieces until we are pleased with the composition of our picture.”  

Page 4 

  1. Creating hand picture. 
    • Tell. “Please open your book to page 4. We are going to create a picture of your hand. Don’t worry, we are going to break it down into parts and build it up piece by piece. Let’s start with the palm.” 
  2. Start with palm. 
    • Tell. “Before you put anything on paper, you’re going to trace the outline of your palm with your finger to identify its shape. Hold up your hand with your palm towards you. Place your pointer finger of your other hand at the base of your thumb at your wrist. Now I would like you to imagine your finger is a pen and trace a line straight up to the base of your pointer finger where it meets your palm. Continue, tracing a line directly to the edge of your palm at the base of your little finger. Next, trace a line from this point down the edge of your palm to the outside of your wrist. Finally, close the shape by drawing a line across your wrist to connect to the place where you started.” 
  3. Interpreting palm shape. 
    • Tell. “Follow that path again quickly and pay attention to the shape your finger is drawing on your hand. Up from the wrist to the pointer, across to the little finger, down to your wrist and across to where you started. What shape are you creating? How many sides? Some of you will have a square, some will have more of a rectangular palm.” 
  4. Interpreting finger shape. 
    • Tell. “Now let’s look at your fingers. I would like to select one finger to draw around with your pointer finger. What shape are you coming up with? Rectangle? So would you agree that your other three fingers are about the same shape too? What is the main difference between them? Right—the length.”  
  5. Selecting paper shapes. 
    • Tell. “Look at the little stack of paper shapes directly in front of your BlackBoard. Find the square that is about palm size. If it is close enough to your palm size, you can glue it to page 4. Please place it near the bottom edge to leave space for your fingers and thumb. Now let’s add the fingers. If you want to modify your palm before you glue it down, you can reshape it with your scissors or cut it using your pen on the BlackBoard.” 
  6. Select paper strips. 
    • Tell. “Find the strips of paper and cut each of them to represent your four fingers. We need to make these proportional to your palm and each other. You can use your thumb and pointer to measure your palm and then see how that relates to your fingers. Is there one finger that is the same size as your palm? Is it longer than all your fingers, or shorter? Cut a shape out of the strip of paper to represent all four fingers. Pay attention to where your fingers are attached to your palm and glue each into position.”  
  7. Select thumb paper piece. 
    • Tell. “Finally look at your thumb. Take some time to find the big shape. I have some trapezoids in that stack of paper that I think might work. Can you modify it to make the outline more closely approximate your thumb? Once you have a satisfactory shape look closely at how it is positioned on your palm. Go ahead and glue it down.”  
    • Note: If students finish early, instruct them to play around with some other modifications to make their picture look more accurate.     
  8. Create new shapes. 
    • Tell. “For this first very complex image we modified precut shapes. Next, I would like to show you how to create shapes of all sizes which will give you greater control over your final products. This is fun. Draw a closed shape by ending your next line at the same place you started your line. A circle is a closed shape, so what can you draw? The sun?”  
  9. Cut out closed shapes. 
    • Tell. “Draw a number of basic closed shapes, pressing down with your pen enough to cut out the shape. These can be based on real or imagined objects. They can be realistic or abstract. We have three different kinds of paper to play around with. Go ahead and cut out five to ten shapes. Keep track of them.”  
  10. Create your composition. 
    • Tell. “Select a new sheet of paper and arrange your objects on the page. Move them around until you like how they are arranged and then glue them down. This should be fun because there is no right or wrong answer. You are arranging your composition on the picture plane.” 
  11. Examining a picture. 
    • Tell. “Please turn to page 5. Let’s examine this picture (a plant). Can anyone tell me what this picture is? How can you tell that? Describe the image and describe the labels. What could we do to quickly add even more information? What if we added a title? What about a caption?” 
  12. Examining labels on a picture. 
    • Tell. “Turn to page 6. This is an image of a simple building with an uneven roof line. In this illustration we have two types of labels to examine. The solid bold line describes the outline of the building. The dotted lines define the length of each dimension. For example, if you go to the upper left-hand side of the roof line and then follow up the dotted lines to the parallel line that connects them you can see that that is labeled with a written dimension. What does it read?” 
  13. Labels and dimensions. 
    • Tell. “If you look below the roof and stay on the left-hand side of the building, what do you find? What is the measurement describing? Using this technique you add the dimensions or the words like the plant labels in picture 5 directly onto the drawing. Labels and dimensions are critical components of technical drawings.” 
  14. Using labels with keys. 
    • Tell. “Another technique for labeling drawings is to use pre-printed alphabet stickers and a key. A key is a list of detailed information printed on a separate piece of paper. You find the information you are looking for by finding the letter associated with that part of the drawing and then going to that same letter on the key and reading the entry with that information. Look at the bottom of the building on page 6. Identify what dimension B is describing. Identify what dimension C is describing. To use pre-printed labels, you place a letter on the drawing in the same spot where the dimension or label would go. Then, on a separate piece of paper you create a key by writing each letter and the associated dimension or label. You may have seen keys used on maps or on other tactile graphics.” 
  15. Make your own labels and key. 
    • Tell. “Find the sheet of preprinted labels in your folder. We are going to use these to capture the measurements on a drawing that you create.”  
  16. Plan your picture. 
    • Tell. “Find the two wooden blocks. If you put the triangular one on top of the other, they can represent a house. Choose a side to illustrate in your picture. Do you want to show the triangular shape on the end of the gabled roof? If you want to show the side of the house, what shape would you make the roof? Can you outline it with your finger and analyze the outline?”   
  17. Draw and label. 
    • Tell. “There are some cut out geometric paper shapes on the table. Glue one or more onto a sheet of paper to create the shape of your building. I would like you to draw dotted lines perpendicular to the height of the building and label it with an “A” sticker. Next, I would like you to draw dimension lines perpendicular to the width of your building and label it with a “B” sticker. Now you are going to create a key on another page for your A and B dimensions. Measure the length of the A line and the B line and enter that information in your key.”   
  18. Finish the drawing. 
    • Tell. “What do you think are the pros and cons of these two techniques for labeling images as you draw? If you have extra time you can add more details. Are there any birds? A sun in the sky? What about a tree?” 
    • Note: Instruct students to keep track of their label stickers since they will need them for future drawings throughout the project.  

Station 3: Isometric Perspective 

  1. Orienting to the station. 
    • Tell. “Check out the tools at your desk. You should have a 3” cube, which is what you're going to draw, a Sensational Drafting Board with a horizontal bar, a 30º/60º/90º triangle with notches every inch, a pen, and a roll of masking tape.” 
  2. Setting up Sensational Drafting Board. 
    • Tell. “Tape a piece of paper to your Sensational Drafting Board. Please examine the drafting board. There is a horizontal bar that moves up and down over your board. Because it's a Sensational Drafting Board, the bar sticks to the surface of the board. If you push the ends of the horizontal bar up from beneath, it will freely move up and down across your paper. Make sure you get the bar up and over your paper. Move the bar so that it covers about an inch of paper at the bottom. Now tighten the end knobs on the left and right side of the bar to secure it in position.  
  3. Adjusting the Sensational Drafting Board. 
    • Tell. “The two knobs on top of the horizontal bar at each end are for re-adjusting the bar if it gets out of square or if it is slanted and not exactly horizontal. If it is square, you don't want to loosen those knobs.” 
  4. The isometric drawing. 
    • Tell. “There are a number of different perspective techniques that artists, designers, scientists, and engineers use to portray real or imagined 3D objects on a 2D plane. One of these techniques is the isometric drawing. At this station, we are going to learn the rules that govern how an isometric drawing is created.” 
  5. Uses for isometric drawings. 
    • Tell. “Engineers most often use isometric perspective for technical drawing of smaller objects like tools. For example, an isometric projection often appears on a multi-view drawing to convey features of the object to those who do not have technical training. Interior designers frequently use isometric perspective to illustrate the inside of a room, and architects use isometric perspective to depict buildings for their clients.” 
  6. Three rules of isometric perspective. 
    • Tell. “In isometric perspective the three primary rules are:  
      • “The vertical edges of an object are illustrated as vertical lines. Look at your cube model. Please locate the vertical edges of the cube. How many vertical edges can you find from this perspective or point of perception? Using this perspective technique, we don’t reach around corners; so some parts of the cube won’t end up in the drawing.”  
      • “The second rule is that a horizontal line is illustrated at a 30º angle. Can you count the number of horizontal edges that you can find from your perspective on this cube? Look at the drawing of the cube on page 9. This is the image we are going to draw. It is a cube in the same position as our cube model. Can you show me on your model which surfaces of the cube are illustrated in this image?”  
      • “The third rule is that you draw all the dimensions in scale to the actual object. We will be drawing a 3” cube in a 1 to 1 scale. How long will the line be for each edge of this cube?”  
  7. Draw the first line. 
    • Tell” Let’s draw. Find the vertical edge closest to you on the model. That is the first line of the illustration that you will draw. Will you draw that line vertically or at a 30º angle? You will start by drawing a 3” vertical line up from the horizontal bar which is your baseline. To make sure that this line is exactly straight and vertical, place a triangle flush on the horizontal bar so that the right angle of the triangle is sitting on the bar. Then you can trace along the edge of the triangle to get a line that is perfectly straight. Make sure you start and stop your line with a good firm period so that it is as clear as possible. Make sure to draw hard enough so you can feel the entire line. Move the triangle out of the way and take a moment to feel the first line that you just drew.”  
  8. Draw the horizontal lines. 
    • Tell. “Please go to the model and go to the bottom of the edge you just drew, the vertical edge closest to you. What edges connect to this edge? Are they horizontal or vertical? Next, we need to draw these two horizontal edges so that they connect to the vertical line we just drew. In isometric perspective the dimensions of the object are drawn to scale. What scale are we using here? Our first line was 3” and our object is 3” so it is a one-to-one scale or actual size. So how long will our horizontal lines be? To draw this horizontal line correctly we need to pay close attention:” 
      • “We need to draw a 30º angle by placing our triangle flush on the horizontal bar with the 30º angle next to the bottom of our first line” 
      • “We need to locate the bottom of our first line with our pen so that when we begin to draw this new line will be connected with the first line.”  
      • “We need to draw a three-inch line to the left and then to the right. Flip your triangle to get the two different sides.”   
  9. Draw the vertical lines. 
    • Tell. “Next let’s draw the two outside vertical lines. Where will they start? How long will they be? How are you going to adjust the triangle to create a 3” line? You also have calipers. If you would like you can use them to measure a 3” line.”   
  10. Draw the next horizontal lines. 
    • Tell. “What lines do we still have to draw? Which should we draw next? Go ahead and draw the two horizontal lines that extend from the top of our first vertical line to the left and the right and connect with the outside left and right vertical.”  
  11. Draw the last two lines. 
    • Tell. “Last two lines! Can you all show me what is left to be drawn on the model and sample drawing? Go ahead and draw those two lines. If you aren’t quite clear about what is happening, let me know, and I am happy to help.” 
  12. Examining hidden lines. 
    • Tell. “Look at the drawing on page 7. This is basically the same as the drawing that you just created. Now turn to page 8. What do you think this next drawing is illustrating? Can you tell me what is different from the drawing on page 7? Do you remember how we illustrate hidden lines from the truncated cone exercise? Let’s take a minute and look at the hidden lines on the sample drawing on page 8. Can you show me which lines are the hidden lines illustrated on the model?”  
  13. Examine rectangular block picture. 
    • Tell. “Turn to page 9 to look at the rectangular block. How could you tell what size this object is?” 

Station 4: Picture Analysis 

Description: This activity gives students an opportunity to analyze images in a structured way that can teach them how to systematically observe and determine what is contained in an image.  

This activity consists of matching tactile images to a 3D print house. There are 5 images that match the house model and 15 other images that are of a house but not exactly the model house. Some (9) have one feature that does not match, and some (6) have 2 features that are different. 

  1. Five matching images. 
    • Do. You can begin by giving the students the 5 images that match each of the 5 sides. Each student can figure out what view of the model each image describes.  
  2. Challenge. 
    • Do. Once they have accomplished the task of matching the 5 matching images, you can challenge them to mix all the images together and then separate the images into stacks of matching images: 1-difference images (9) and 2-difference images (6).  

Note: For additional tasks to do with the house and cards, you can read the Encore lesson plans that start on page 71 of the Encore activity lesson plans from American Printing House for the Blind.  

The APH Setting the Stage Tactile House Model; a plastic model with the dimensions 3.8 x 3.05 x 3.15 inches.

Station 5: Orthographic Projection 

  1. Orthographic projections. 
    • Tell. “As we have learned, orthographic projection is useful for engineers who need to have precise measurements and a clear understanding of the objects they are designing or manufacturing. It might be easiest to imagine putting the object into a box. We can then draw the outline of the object from each of the six directions or sides of the box. Many times, we will get enough information from three views, top, front side, and right side to get all the information we need to understand the shape.” 
  2. Pretend to take a picture. 
    • Tell. “We are going to approach this in a couple of different ways. First, we will take some pictures. I think you will all be familiar with this. Can you each pretend that this frame is a camera and take a picture of me? Each of you aimed your camera/frame at me. You knew to position your frame so that I would show up on the picture plane, right? If you were to reach your hand or cane through the picture frame, you would be able to reach forward and find me. That places me on the picture plane.”  
  3. Practice finding the picture plane. 
    • Tell. “Turn to page 10. Use the picture frame to isolate the necessary components on the Sun, House, Girl handout to create the image on page 10 (sun and house). Which 2 components from the handout do you need to appear in the picture to create the picture on page 10 (sun and house)? Have you found it? Next turn to page 11. Note that this page is in portrait orientation, so you will need to turn it to read it properly. Use your picture frame to isolate the two components that make up the picture on page 11 (house and girl). Do the same for page 12.” 
    • Do. Make sure each student has the 8.5” x 11” image of “Sun, House and Girl” and their picture frame.  
    • Note: Each of the images that the students will be framing are captured by moving the picture frame into a different position on the image of the sun, the house, and the girl. 
  4. Your own frame. 
    • Tell. “The beauty of being able to create your own pictures is that you can modify by adding, eliminating, or manipulating objects in your picture. It gives you a lot of freedom to express your ideas.” 
    • Note: The students will find that by framing an image differently they can create entirely different pictures. The first is a landscape of a sun and a house, the next is a portrait image of a girl in the foreground and a house in the distance. The third is only the house.   
  5. Practice drawing the framed object. 
    • Tell. “Let’s try one more exercise. Please place your frame on the table in front of you. I will be arranging an object in the window on the picture plane. Remember, the inside of the frame is at the edge of your paper picture. If something is in the upper right-hand corner within the picture frame, you will draw that object in the upper right hand corner of your paper.” 
    • Do. Place an object in each student’s frame. Feel free to use any objects from around the area. The objects may go off the edge of the picture plane. It’s a little easier if you use objects with a low profile.  
  6. Discuss the frame. 
    • Tell. “Some objects will extend off the picture plane. Remember the inside of the frame is at the edge of your paper picture. So, if something runs off the picture plane, under the picture frame, it is running off your paper at that point as well. How much of each object can you see or feel? Is it all on the picture plane?” 
  7. Draw. 
    • Tell. “Let’s draw the picture that is on your picture plane. Place a clean piece of paper on your board. Locate your objects in the frame. Are they on the left or right or in the middle? How far is each item from the top of the frame? Using the edges of your paper to represent the inside edges of your frame, can you locate and draw the objects on your paper?” 
  8. Other examples using orthographic projection.  
    • Tell. “We will continue to explore the idea of orthographic projection with some miniature doghouses. Page 13 illustrates the 3 different types of roofs that our doghouses have. An orthographic image is created by actually placing an object into a box or by imaging the object as if it were in a box. The box defines six different directions that the object can be accessed from: front, right side, back, left side, top, and bottom. Often, enough information can be gathered from the front, top, and right side. But if more information is needed, all six sides can be illustrated. It is important to understand that the outline of the object is projected straight onto the surface of the box. Imagine your pen always staying perpendicular to the box surface as it traces around the object.” 
  9. Matching models to orthographic projections. 
    • Tell. “Turn to page 14. An orthographic projection is frequently used to communicate information to manufacturers because the way we represent the views allows us to convey size and locate detailed information. It is a convention that is especially useful for clarifying exact dimensions of objects. Pick up one of the model houses in front of you. It doesn’t matter which one. I would like you to look at the pictures that are illustrated on the page. There are three rows of four images. See if you can find the row that illustrates the model you have in your hand right now. “ 
  10. Reviewing the images. 
    • Tell “We are going to go through the images together. The first image on the left is the front elevation of the house. The model does not have a door, but if it had the door that is drawn into the image, where would that be? The second image shows the model from the right-hand elevation. Can you trace the outline to see how it correlates to the right-hand side of the model? The third image is a top view. What do you notice that is common to all the models? What is unique? Finally, the right hand image is a floor plan. Can you tell where the door is located?” 
  11. Matching templates to models. 
    • Tell. “Line the three doghouse models up in front of you. Find the stack of templates. Position each doghouse to align with the templates. When you match the correct template to the correct doghouse you will be able to fit the doghouse through the window which shows the outline of the house from the front elevation, and the top view and the right side view. Find the template that describes each house. These houses have similar dimensions; double check to be sure that the projections match up on all the views.” 

Standards Alignment 

NGSS Standards Alignment:

  • SEP 2 - Developing and using models 
  • CCC 6 - Structure and function 
  • HS-ETS1-2 

CCSS Standards Alignment:

  • CC.9-12.G.CO.12, CC.9-12.G.GMD.4, CC.9-12.G.MG.1, CC.9-12.G.MG.3 

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