Using Alice to Introduce Programming Concepts

Mr. Craig HamTechnology Coordinator

Westminster Schools of AugustaAugusta, GA

Computer Science

It’s crucial we begin to push CS at the secondary level

US Dept Labor predicts CS jobs will be the fastest growing and highest paying over the next decade

CS Provides 21st Century skills necessary for innovation. Job demand is growing and by 2016 estimates are 1.5 million jobs in CS

What Can Your School Do to Successfully Incorporate CS Education?

Implement CS classes. Rigorous and engaging.

Allow CS to count toward graduation (as math or science)

Make courses accessible for all. Recruit those underrepresented.

Improve teacher preparation and professional development.

How Does Alice Fit In?

Alice is designed to engage students with the designs of programming but without the tedium of syntax and error checking.

Additionally it creates all this in a 3 dimensional space instead of text on the screen.

What is and what can I do with Alice?

Alice is a modern programming environment designed to be a student's first exposure to object-oriented programming. It allows students to learn basic computer science while creating animated movies, simple video games, where students control the behavior of 3D objects and characters in a virtual world.

Updates, Releases, Fixes

New releases each Spring and FallLook for ver 2.2 and the most current date

with is 8/5/2011Versions for both Mac and PCAfter you download (351 MB)Copy the Alice 2.2 Folder-no installRun Alice from the folder

Several Good Books out there

Text by Charles Hebert

What I Hope to Cover

Alice screen layout overviewPositioning, Resizing, Moving ObjectsMotion and OrientationOther things that “pop” into my headYour questions!

Most of the follow slides were created by Wanda Dann, Steve Cooper, and Don Slater at Carnegie Mellon University

Alice Code Editor

Object tree

Control Structures

Object details

Events Editor

World View

Go to Scene Editor

Demo & Practice

Go to Scene Editor of this project (click on Add Objects button)

aliceLiddell (People gallery) hare (Animal gallery) axes (Shapes gallery)

Identify the center of each object. Identify the forward direction of each. Identify the up direction of each.

Motion Motion of an object is relative to

the orientation of the object the location of the object

• Location is defined by an objects center point (or pivot point)

The art of Alice animation is manipulating the location and orientation of an object and / or its subparts to create the illusion of motion.

Orientation

Orientation is an object’s sense of direction A 3D object has

3 dimensions• height, width, depth

6 directions of motion

Center of an object An object is positioned in the world, with

reference to the center of the object. The center of an object can be:

At the center of mass, or

Where it stands on the ground, or

Where it is held or connected (for example, a hinge joint)

Alice Scene Editor

Object tree

Gallery

Object details

Camera Controls

Mouse Control

World View

Return to Code View

Translational Motion

Changes position of an object in the world The direction of translational motion is stated

relative to the self-centric orientation of the object. Six directions

• moveleftrightupdownforward backward

Bounding Box Viewing the intersection of axes in an object’s bounding box is one way to determine where the center of an object is located.

Set-up methodsTo illustrate object motion, we will use the

object’s popup menu of menu methods.

Process for using a set-up method: Right-click on the axes from the object tree or

in the world Select methods from the list Select a method from the list

Selecting a menu method: orient to

Right-click on axes

Demo & Practice

Use a menu move instruction with aliceLiddell hare axes

Note: You can click the Undo button to return an object to its

initial position before trying another move.

Question

Other than move, what other methods in the menu can be used for “translational motion”?

Using Alice to Introduce Programming Concepts

Mr. Craig HamTechnology Coordinator

Westminster Schools of AugustaAugusta, GA

Rotational Motion

Rotational motion changes the orientation of an object in the world

An object’s center acts as its pivot point for rotation of the whole object.

Two forms of rotational motion:• turn

forward, backwardleft, right

• rollleft, right

Hands-On Practice

Compare turn and roll menu methods with aliceLiddell and the hare

Note:Be sure to click the Undo button to return to initial position before trying another rotational motion.

How would you describe the center point of each object? Are they the same?

Question

Other than turn and roll, what other methods in the menu create “rotational motion”?

Rotational Motion: Subpart

Rotational motion of a subpart of an object may have a surprising result Turn and roll actions for a subpart are

pivoted around the center of the subpart, generally located where the subpart connects to the rest of the object

(see example, next slide)

Example The hare’s right arm is centered at the shoulder(the pivot

point) of the upper arm to the body

Note: A few Alice 2 models were designed to work differently and, therefore, do not conform to this example.

Center for a subpart

One way to view the center of a subpart is to move an axes object to the subpart and then orient the axes to the subpart.

Example: hare’s rightArm’s center

Movement of a subpart

One way to view the movement of a subpart is to set the vehicle of the axes to the subpart and then orient the axes to the subpart.

Example: Select axes in the object tree Select properties tab in axes

detail’s window Change vehicle property

using the drop down menu

Review

1TranslationalMotion.a2w

1RotationalMotion.a2w

Open File Menu: World• Click on Examples tab• Click on workshopWorlds

folder• Click on Day1 folder

Text

Additional information on motion instructions may be found in Tips & Techniques 2 Orientation & Movement Instructions

Practice ProblemOpen file 1HelloWorldStart.a2w

The hare is waiting in the garden when Alice enters from the left. (She is off screen at the beginning of the world.) Have the hare turn to greet Alice after she enters. Both say hello to each other. (use the say method of the objects.)

Then they both turn to greet the viewer, with a wave. For an extra challenge, try to have Alice wave her hand. They should return their arms to the original starting position.

Open File Menu: World• Click on Examples tab• Click on workshopWorlds

folder• Click on Day1 folder

Additional Material

The following slides contain additional information, examples and topics that will not be covered explicitly in this workshop. See workshop leader during breaks for more details

Pivot Point Orientation

Different pivot point connections and orientations may be found in 3D objects because Alice 2 models were designed Over several years by dozens of different

graphic artists For many different virtual world projects,

where a variety of connections for subparts were needed

roll and turn

If subparts are connected with pivot points differently, the same roll and turn instructions may result in different actions on different objects. This is particularly noticeable in biped objects

where arms and legs are animated.

Demo

Walking The variations in design and construction

of 3D models make it difficult to write a walking method that can be used for all bipedal objects.

Alice 2.2 has a Walking People gallery containing 3D models for creating “people” objects that already know how to walk look inside the People gallery for Walking

People folder

Walking People Gallery