1. Skater World: Part Two By Deborah Nelson Duke University Under the direction of Professor Susan Rodger June 1, 2009 1

2. Overview The story continues: After the conversation, we want skaterGirl to get on the skateboard, make the jump, and then skate around one of the cones What we will do: 1.Create new methods – Animating parts of an object – Using As Seen By 2.Camera Control – Using Buttons – Using Dummy Objects – Changing Point of View 2

3. Step Two: Methods A method is a sequence of instructions that will be carried out when requested. Built in methods are used to create new methods so that the characters can learn to do more. The two types of methods are class-level and world-level. A class-level (or object-level) method defines the behavior for a single object. A world-level method has objects that interact with each other. 3

4. To Create your method Since our methods involve several objects, we will create world-level methods. Click on world in the object tree. Click on the methods tab in the details areas. Click create new method. Name it “getOnBoard”. Click OK. A new tab appears in the method editor 4

5. The Events Pane – This is where you control when certain methods are called and the user interactions within your animation. Introducing Another Tool 5

6. When the world starts... As we write this new method, we don’t want to watch the entire conversation we wrote from part one every time we play the world. In the Events pane, click on the arrow and select getOnBoard from the drop down menu. 6

7. Writing getOnBoard method In our story, we want the girl to go forward to the skateboard and hop up onto it. Click on the getOnBoard tab in the method editor On top of the Do Nothing drag in skaterGirl move to, select skateboard, the entire skateboard Play your world.  See the next slide for screenshot 7

8. The girls moves into the skateboard because the move to method uses the center of each object. We would have to manually measure how far the skaterGirl needs to move to the skateboard 8

9. To realistically make the skaterGirl move to the skateboard, we will put an invisible object next to the skateboard and have skaterGirl move to that object. Click on Add objects. Go to the Shapes folder. Drag a box into your world. 9

10. Positioning the Box First, we want the skateboard and box oriented correctly. Right-click on the skateboard in the object tree. Select methods, turn to face, jump. Right-click on the box, select methods orient to, 10 skateboard, the entire skateboard

11. Using Quad View Now, click on quad view. Use the move arrow to position the box next to the skateboard. Remember to hold down shift as you drag in order to move up or down 11

12. Step Four: Properties – In the properties tab, set the box’s vehicle property to skateboard the entire skateboard – The vehicle property attaches an object to another object. They always move together Attaching objects together Now that we’ve positioned our box, we want it to stay next to the skateboard, wherever the skateboard moves. 12

13. Understanding vehicle property Click Done to exit the gallery. Drag Do together into the getOnBoard. Drag the following into the Do together: Play your world.  See the next slide to see what went wrong 13

14. Right click on the box instruction and select disable Play your world to see the box move with the skateboard since the skateboard is The box’s vehicle 14 You can see the box move past the skateboard. We only need to move the object that is the vehicle, in this case the skateboard Now that you see how vehicle property works, delete everything in this Do together by dragging it up to the trashcan

15. Properties continued: Making an object invisible Now that the box is positioned and attached, we need to make it invisible. Click on the box in the object tree. Click on the properties tab in the details area Set isShowing to false 15

16. Finally, we can change the color of objects. Click on the cone in the object tree. In the properties tab, change the color to orange. Do this to every cone – You can even change the color of default Alice objects. For example, click on ground in the object tree and change it's color to green. 16

17. Finish writing getOnBoard In the move to instruction, click on the arrow beside the skateboard. Change it to box because we want skaterGirl to move to the box, not the skateboard. 17

18. – Drag in skaterGirl turn, right, 0.3 – Drag in skaterGirl move, up, 0.16 – Drag in skaterGirl move, forward 0.4 – Set the duration of each instruction to 0.4  You will learn how to position and move objects with greater position. For now, you may have to increase the move up amount. 18

19. While skaterGirl is on the board, we want her to move with it, so we must change her vehicle property to skateboard Click on skaterGirl in the object tree. Click on the properties tab. Since we want her vehicle property to be changed during the animation, drag her vehicle property into the getOnBoard method. Set it to skateboard, the entire skateboard. skaterGirl Vehicle 19

20. Calling your method Then drag in world.getOnBoard from the world methods under the conversation instructions from Part One 20 Now let’s call getOnBoard from world.myFirstMethod Click on the world.my first method tab

21. Play Your World 21 – Play Your Entire World – Remember to change the event from getOnBoard to world.my first method

22. Creating makeJump method Click on world in the object tree. In the methods tab, create new method, name it makeJump In this method, the skateboard will turn to face the jump object. Then it will turn up slightly, go over the jump, move forward, and then go back down to the ground 22

23. Call MakeJump Now we need to call our new method. Click on world.my first method. Drag in a Do together. Drag world.makeJump into the Do together Drag skaterGuy turn to face, select “jump” 23

24. Writing Make Jump Click on the makeJump tab to add code to that method When the skateboard turns to face the jump object, skaterGirl’s head will turn right. Since we want this to happen at the same time, first, drag in the control statement, Do together Drag in skateboard turn to face, select jump. 24

25. Animating Parts Of Objects 25 To animate part of an object, expand the object in the object tree by the + Expand skaterGirl, upperBody, neck, Drag head into the Do together. Select turn,right, ¼ revolution. Set duration to 0.5 Result:

26. Next, (underneath the do together), drag in skateboard from the object tree. Select move toward, 1 meter, jump. Change the 1 meter so that the girl moves close to the board when you play your world I changed the amount to 7 meters. Then, click on more in the instruction and change the style to abruptly 26

27. Finish writing makeJump We change the style to abruptly so that there will not be a pause between each instruction Drag in the rest of the instructions underneath the Do together. The complete method is on the next slide.  Notice the change in style and duration of each instruction. Play your world 27

28. The complete method: 28

29. Animating parts of skaterGirl We can make this jump look more realistic by making the skaterGirl bend her knees Click on skaterGirl in the object tree. Click create new method. Name it bendDown. Click OK. Drag in a Do together and the following instructions: 29

30. SkaterGirl legs will bend when the board moves. To do this, click on the makeJump tab. Drag a Do together above the “move forward 4 meter” instruction. Then drag that instruction into the Do together. Click on skaterGirl in the object tree and drag the bendDown method into the Do together. Play your world 30

31. Now that she’s bent, we need a method for her to stand up. That’s the opposite of what we just did. Click on bendDown tab. Drag the whole Do together to the clipboard to make a copy of it. 31

32. Click on the skaterGirl in the object tree. Create a new method named standUp. Drag from the clipboard into standUp to paste what we copied. 32

33. Change move down to move up. Change the Leg instructions from backward to forward. And change the lowerLeg instructions from forward to backward. Now we want skaterGirl to stand up and skate around one of the cones. So let’s write one more new method 33

34. Writing SkateCircle Click on world in the object tree. Click create new method, name it skateCircle, click OK Drag in the following code. *except turn to face whichever cone is closest to the “jump” 34

35. As Seen By To make the skateboard turn around the cone, for the final instruction in skateCircle: 1.Drag in the skateboard turn left, 1 revolution. 2.Click on more, select asSeenBy, cone. Drag skateCircle underneath the instructions in world.my first method Play your world You may have to change the last move forward amount 35

36. Step Five: Camera Control Now let’s learn how to change the camera view. Before the skaterGirl jumps, we want to move the camera in order to watch her jump from the right side. Click on Add Objects. You can move the camera using these buttons: Use only the middle one, click and drag the camera to the right and then drag it forward and swing it around so that you’re looking at your scene from the right side. Try it slowly. Remember to use undo if you make a mistake 36

37. When your scene looks like this, first play your world to make sure that you can still see the conversation and the jump Once you’re satisfied with the camera position, click more controls, then drop dummy at the camera Expand Dummy objects in the object tree. Rename ‘Dummy’ as “sideView” 37

38. Changing the View in the animation Click Done to exit the layout mode Now that we have multiple views, we must specify the view at the beginning of the animation. Drag camera from the object tree into the very beginning of world.my first method. Select set point of view, Dummy Objects, originalPosition. Set duration to 0.  See the next slide for the screenshot 38

39. Set Point of View to Dummy Object Then, right after world.getOnBoard, drag camera set point of view, select Dummy Objects, sideView Play your world This screenshot shows setting the camera point of view to the originalPosition. 39

40. Set point of View to an Object Another way to change the point of view of the camera is to set it to a character. Let’s set the view to skaterGirl. Before the call to skateCircle, drag in the camera and select set point of view. Select skaterGirl, select her head, the entire head. Play your world.  See the next slide for an explanation of what went wrong 40

41. When you play the world, the skaterGirl moves, but the camera doesn’t move with her. Drag in a Do together above the call for skateCircles. Drag the “set point of view to skater girl’s head” instruction into it. Then drag camera into the do together and select set vehicle, select the skaterGirl’s head. 41

42. World.myFirstMethod The current version of myFirstMethod, after the conversation:  Congratulations on finishing Part Two. In Part Three, you will learn how to interact with your animations 42