Creating a 3D Interactive Story

Prof. Susan Rodger

Duke University

Feb. 24, 2007

Now Create an Alice World

• Start Alice

• Select “File”, “New World”

• Click on Snow picture

• Click on “Open”

Find SnowPeople objects

• Click on “add objects”

• Scroll over to “people” folder and click on it

• Scroll over to Snowman and snowWoman

Add Snowman to World

• Click on snowman and you will see:

• Click on “Add instance”

• Snowman appears in world

Add SnowWoman to world and adjust

• Click on SnowWoman and add her to the world

• Click on arrow key• Click and hold on snowman

to move him left and back• Click and hold on

snowWoman and move her to the right

• Scene should look like

Save World

• Save world

• Type in a name such as: snowPeople and then “save”

• Alice will remind you to save your work every 15 minutes

Now Ready to program!

• Click on done

• Should now see myFirstMethod

Write code to move the snowman• This is the object tree, a list of

all your objects in the world• Now click on the word

“snowman” to highlight it

• You should see methods below it (things the snowman can do) such as move, turn, roll, …

• Scroll down til you see “turn to face”

Write code to move the snowman (2)• Click left mouse button on “snowman turn

to face” AND HOLD IT DOWN, then Drag it over and release the mouse button

• Click on “snowWoman”

• “the entire snowWoman”

Write code to move the snowman (3)

• Code appears

• Click on Play

Have the snowman talk

• Drag over “Snowman Say”

• Select “other” and type a greeting such as “Hello there!

• Code is now:

• Play again

Now SnowWoman will act• Click on snowWoman to see her

methods

• Drag over code and drop below other code

• Play!

Now write a NEW snowman method• Click on snowman

• Should see snowman’s methods

• Click on “create new method” and enter name “getAttention”

• Empty method is created, ready for you to enter code

Write GetAttention Method• Add the following code to this method

• Note you now have two methods:

• Click on myFirstMethod to get back to it

Add getAttention method to program – to myFirstMethod

• Click on play

Repetition• Sometimes you want to repeat

commands • Let’s repeat “getAttention” three

times• Click on “loop” and drag and drop at

the end of our code, below getAttention– Select “other” and type 3

– Click on left tab of “getAttention and move it inside the loop

– Now Play!

Create snowman method - popHat

• Click on snowman in objectTree

• select “create new method” and name it popHat

Want the “topHat” part of snowman• Click on + by snowman

• Click on + by head

• click on tophat to highlight it

Now we will move just the tophat

• Drag over the “move” command twice to make the tophat move up and then down the same amount

Make an Event

• We want the hat to move up and down whenever we press the “H” key

• Create a new event and select “when a key is typed”

• Click on “any key” and select the “letters” then “H”

• Click on “nothing” and select “snowman” “popHat”

Making an Event happen

• Play your world

• Whenever you want the hat to pop up and down, just press the key “H”

Add more code to myFirstMethod

• At the end of your code in myFirstMethod– Add code to have the snowWoman turn toward

the snowman, say “I said hello” and turn back

• Remember to click on the word snowWoman in the objectTree to get snowWoman methods

Here is one possible way

Turn SnowWoman’s Head red

• In addition to methods, each object also has properties you can drag and change

• Select “SnowWoman’s Head in the object tree

• Select the Properties tab

Turn SnowWoman’s Head Red (2)

• Click on color, hold and drag to right before snowWoman says “I said hello”

• Select color “red” and release, results in:

At end, turn head back to “no color”

• Here are the two color statements added to the code (note: “no color shows as white”)

• Play your world

Write a snowman Flip method• Make sure you select “snowman” in the objectTree• Create the method named “flip”• Have the snowman do the following

– Move up 1 meter– Roll left 2 revolutions– Move down 1 meter

• Add code at the end of myFirstMethod– Snowman says “Watch what I can do”– SnowWoman turns to look at him– Call the snowman flip method

• Play your world

Write a snowWoman flip method• Make sure you select “snowWoman” in the

objectTree, then create the method “flip”

• Have the snowWoman do the following– Move up 1 meter– Drag up a DoTogether from the bottom

Write a snowWoman flip method (2)

• Inside the DoTogether you can put commands that will happen at the same time

• Inside this DoTogether have the snowWoman do the following:– Turn forward 1 revolution– Resize by half

• Below drop in another DoTogether with:– Turn forward 1 revolution– Resize by 2 (back to the right size)

• Add one more command to move snowWoman down 1 meter

Now let’s call the SnowWoman flip method

• Add code at the bottom of myFirstWorld– SnowWoman should say “Watch what I can

do”– Call the snowWoman flip method

• Play your world

Here is what flip should look like

Add two new events• Add an event so the snowman flips when M

is pressed

• Add an event so the snowWoman flips when W is pressed

• Play the world, press M and W anytime

Add more objects to the world

• First let’s add two more objects

• Click on “Add objects”, find the “nature folder” and add any tree to the world

• Click on it and push it far back

• Find the “vehicles” folder and find the scooter, add it to the world (you may have to look in the Web gallery to find the scooter)

Adjust the scooter

• Click on the third control and try turning the scooter around to face this direction

• Then click on the first control (the arrow) and push the scooter back between the tree and the snowWoman

Write the SnowWoman method driveAway

• First select the snowWoman in the objectTree and create a new method named “driveAway”

• Now let’s add code to this method• First have the snowWoman turn to face the

backRightFloor (or may be called RightFloor) part of the scooter

Move SnowWoman to the scooter

• It will be handy to test this method as we build it, look at the event “When the world starts”

• Click on the white arrow and select “snowWoman.driveAway”

• Now when the world starts, only this method will play – Click Play and see

Write snowWoman driveAway (2)

• We want the snowWoman to move to the scooter.backRightFloor, but we don’t know how far it is

• Have the snowWoman move forward 1 meter and Play it

• It’s not quite far enough

Write snowWoman driveAway (3)• We can use a snowWoman function to drop in the

distance to the scooter.backRightFloor

• Click on SnowWoman functions

• Drag “distance to” and drop on “1 meter” when it turns green, then select “scooter.backRightFloor”

Write snowWoman driveAway (4)

• Play the world

• It is hard to tell, but she goes right into the scooter.

• We’d like her to stop in front of the scooter.

• Click on the last arrow and select “math”, then “minus” then “0.5”

• Now she stops 0.5 meters in front of it

Write snowWoman driveAway (5)• Next, have the snowWoman doTogether

– move up 0.2 meters– Move forward 0.5 meters

• We’d like the scooter to move and have the snowWoman move with it

• We can set the vehicle property of the snowWoman to be the scooter

Write snowWoman driveAway (6)• Click on snowWoman’s properties

• Drag over “vehicle” and select “scooter”

Write snowWoman driveAway (7)

• Almost done, add a few more commands• In a DoTogether

– The snowWoman says “Bye”– The scooter moves forward 10 meters– The snowman’s head turns ¼ turn to the left

(make sure you select snowman in the objectTree)

• One more command after the DoTogether– Snowman’s head turns back ¼ turn to the right

snowWoman driveAway – final code

Call snowWoman driveAway

• Back in myFirstMethod, add a call at the end of your code to call the method snowWoman.driveAway

• Fix the first event so that when the world starts, world.myFirstMethod is called

• Play

Write a snowman melt method• Add a snowman method named “melt”

• The code should repeat 12 times– Move the snowman down a little (0.1 meters)– Wait 0.5 seconds (drag the “wait” tile up from

the bottom)

• At the end of myFirstMethod, call melt

• Play the world

Almost Done – add title• Click on “add objects”

and go to the right end of the local gallery and find 3D text

• Click on it and add a short title such as “Life as SnowPeople”

• You’ll have to use the control keys to move it up, back, and turn it to face the right way (use first three controls)

Title only in the beginning• Notice the title is an object in the

objectTree - Click on it

• We would like it to disappear after the snowman says “hello there”

• Drag over the “isShowing” property and set it to false

Add “The End”• Add another 3D text that says “The End” and

position it over the title

• Click on THE END in the objectTree

• In properties, click on “true” of “isShowing” and select “false” – The End will disappear

Make “The End” Reappear

• Make “The End” visible before the snowman melts

You are now done!

• Play your world!

• You can download Alice for free at

www.alice.org

• My web page

www.cs.duke.edu/~rodger