As a review from the previous lesson, discuss the role of isometric drawings as one way to represent a three dimensional figure. In this lesson, students will compare isometric drawings with another type of representation, namely the front-right-top (FRT) view.
For example, project the following images onto the overhead projector or television monitor:
Isometric Representation:
Front-Right-Top Representation:
The following PDF will allow you to print out the above images on an overhead transparency:
Ask students to discuss, with a partner, what they notice about each of these representations. They may discuss the benefits of using each kind of representation. Some students may say they think it is easier to draw one representation over the other. Or they may discuss how they could use the isometric drawing tool to create each of these representations.
Using the View tool and the Rotation controls on the Isometric Drawing Tool, students should do the following:
- Create a three dimensional figure out of cubes. The figure should be somewhat complicated, such as the one students just saw.
- Use the View button to see a 3D view.
- Uncheck the 3D "box" to see a Front-Right-Top view.
- Check the 3D box to see the three-dimensional view once again.
As students are moving between views, they should observe how the views change and how they relate to the original three dimensional figure they created.
Going back to the original figure and view they created, students should delete one cube from their picture. Ask them to note what they observe about the Front-Top-Right view. Students should continue deleting cubes. Ask them to note the fewest number of cubes they can delete to make the front view look different, the right view look different, and the top view look different. If needed, students can try again using another figure they have created.
The next portion of the lesson will focus on students building the three dimensional figures when given the Front-Right-Top views.
Project the following images onto the overhead projector or television monitor for students to see:
(These images are located on the same PDF as the images previously projected.)
Using the isometric drawing tool, students should construct isometric drawings that match each set of FRT views. Then, they should copy these drawings onto isometric dot paper. You may wish to encourage students to keep the FRT tool open while they draw.
As students finish their drawings, they can compare their results with their partners. Did they get the same drawings? Have students discuss any variations with their partners.
