1. Classes and Objects Wanda Dann Don Slater wpdann@andrew.cmu.edu
Copyright 2012 Wanda Dann, Don Slater
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2. Alice Environment Classes Objects Scene Editor Code Editor
Copyright 2012 Wanda Dann, Don Slater
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3. Each 3D model is a pre-written class In Alice, a class defines
A plan for constructing an object in an Alice scene
Actions an object of that class can perform
These buttons in the gallery
display the classes that are available in Alice
can be thought of as instance creation buttons
Copyright 2012 Wanda Dann, Don Slater
All rights reserved

4. An Alice class is similar to an architect's blueprint for building a house.
Not the actual house -- just a plan for constructing a house, based on a sketch of what it will look like.
Copyright 2012 Wanda Dann, Don Slater
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5. An instance of a class is an object
The following slides illustrate how to create (construct) an object in an Alice scene.
Copyright 2012 Wanda Dann, Don Slater
All rights reserved

6. Where the program for the animation or game is written
Code Editor
Code editor
Scene view
Methods panel
Control tiles
Where the program for the animation or game is written
Copyright 2012 Wanda Dann, Don Slater
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7. Click on Setup Scene to go to the Scene Editor
Go to Scene Editor
Click on Setup Scene to go to the Scene Editor
Copyright 2012 Wanda Dann, Don Slater
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8. Where the scene for the animation or game is created
Scene Editor
Scene setup panel
Where the scene for the animation or game is created
Gallery panel
Copyright 2012 Wanda Dann, Don Slater
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9. Gallery folders In the gallery, classes are organized in folders.
Each class folder is like a drawer in a file cabinet, where all classes of the same type are stored.
Flyer (has wings and can fly)
Biped (walks on 2 legs)
Quadraped (walks on 4 legs)
Swimmer (lives in water, swims)
Copyright 2012 Wanda Dann, Don Slater
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10. Select class folder
Select the class folder for the type of object that you wish to add to the scene.
In this example, we click on Quadruped.
Copyright 2012 Wanda Dann, Don Slater
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11. Quadruped – walks on 4 legs
Within the Quadruped folder are images of each class in this folder.
Each image is labeled with the name of the class and shows a preview for an instance of that class.
Copyright 2012 Wanda Dann, Don Slater
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12. Select class
Click on the image to select one of 5 versions of the BabyDragon class.
5 different BabyDragon
classes
Copyright 2012 Wanda Dann, Don Slater
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13. Select class Click on the image to create a new BabyDragon object
Copyright 2012 Wanda Dann, Don Slater
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14. Adding a Camel object to a Scene
Enter a name for the new object you are constructing from the BabyDragon class

15. Instance/object
We have constructed an instance of the BabyDragon class and identified it with the name fergie.
We say an instance of a class is an object.
Copyright 2012 Wanda Dann, Don Slater
All rights reserved

16. Instance construction - Alternative
An instance of an object may be added to a scene by clicking and dragging the image into the scene view.

17. Instances of same class
Can have more than one instance of the same class.
Example: fergie and bert are two instances of the BabyDragon class.