objects and properties alice. objects in alice objects already exist. hundreds of them
Post on 14-Dec-2015
229 Views
Preview:
TRANSCRIPT
Objects and Properties
Alice
Objects in AliceObjects already exist. Hundreds of them
ObjectsIn the demo worlds, the octopus and skater are objects.An "object" is
anything that can be identified as unique from other things
How is an object identified as unique? has a name has properties:
width, height, color, location, age, ss#, id#
has a purpose:associated actions it can performtasks it can carry out
Objects in a Virtual World
In Alice, each 3D model is a class of objects
each object of the class has a unique namemummy, mummy1, mummy2
has color(s)pink, white, grey, black, blue, ….
Objects in the WorldCan have multiple instances of objects from the same class in the World
class: like a cookie cutter
objects: like the cookies
star cookie cutterstar cookie class
star cookiesstar cookie objects
Objects in the World
penguin class penguin objects in a virtual world
Object DimensionsObjects in Alice worlds are 3 dimensional
height width depth
Objects “Know” Relative Directions
Yellow box around penguin is itsbounding boxlight blue line is up/downpink line is left/rightdark blue line isforward backwardDEMO
Galleries of 3D Objects
Sources of 3D objects the local gallery shipped with the software
Alice web gallery
Objects in a Virtual WorldIn Alice, each 3D model is a class of objects
class: penguin
objects: penguin, penguin2, penguin3
Problem
Suppose I want a Penguin to disappear from the screen during the animation.
Solution
The solution is to change the opacity (degree of transparency) while the animation is running.Opacity is a property of the penguin object.All objects in Alice have properties, which include (among others):
location (x, y, z)orientationcoloropacityvehicle
Changing Properties of ObejctsProperties of Object can be changedLocation can be changed by clicking and moving objectOrientation can be changed in the “Add Objects” ViewOther properties, such as color, can be changed in the properties window when the object is selected
Object PartsObjects may be composed of parts
which may in turn be composed of parts
the whole object may be told to do something or an individual part
Object Parts
Objects may be composed of parts
3D objectsA 3D object has
3 dimensionsheight, width, depth
6 degrees of freedom (directions of movement)
Distanceobject’s distance from each other are based on the distance between their center points
may look like objects are zero distance away, but actually centers still some positive distance away
Position in the WorldThe world in an Alice program models a 3D spaceevery object in the world has a positionx, y, z, coordinate relative to the center of the worldground starts at center of worldaxes (green = up, red = right, blue = forward)
VehiclesEach object has a vehicle property
Initially the world is the vehicle for objects
can change this by altering the vehicle property for an object
Give the snowman an instrument
Change “ahem” to “toot”
What happens when movie played?
Alter the Vehicle PropertySelect sax from object tree
Select properties tab
Change vehicle from world to snowman
Assignment
Read Tutorial03 Know what an object is instance of
Know how to use the properties
Read Tips & Techniques 2 Orientation and Movement Instructions
Lab 03
Penguin
Tortoise and the cookie
Mana and the magnet
top related