Questions on E-Toy Scripting of Alice (3-D)

Mark Guzdial guzdial at
Tue Sep 4 13:46:13 PDT 2001

I have some questions about using E-Toys to script 3-D objects in Alice.

It's amazingly cool.  There's a lot of power here in getting 
non-technical peole interested in Squeak and in programming, I 
believe. I played with it with my 9 year old son, Matthew, last 
night.  It was striking to me that the E-Toy scripting stuff pulled 
him in, but he quickly wanted to do things that were easier in the 
Alice/text-scripting window.  I built him a game using joystick 
control of objects (see below), but when he started building his own 
world, he was often asking me about the textual side of things. 
"dragon1 move: up" was faster for him than finding the dragon1 
viewer, finding the y, and increasing it enough.


- I know (from talking to Andreas) that the plugin currently doesn't 
support 3-D, so we can't use Alice in the browser.  Is there a way to 
add-in 3-D support if we need it, e.g., put a DLL in the VM 
directory, add a file-in to the image, etc.?  Or are there any plans 
to eventually add 3-D to the existing plugin?

- I was trying to figure out how to make one object respond to 
another one being close.  I wanted to make a sound occur when the 
WhiteRabbit got close to the banana in my world.  I found that I 
could create a tile phrase WhiteRabbit distanceTo: banana, but this 
returned a number.  I couldn't figure out how to set up a test with 
this, e.g., when the distance to the banana is less than 0.5 meter. 
I eventually changed my script into text and typed in the test I 
wanted, and then it worked.

- Alice objects don't understand a lot of the basic operations of 
Morphic objects, e.g., Alice objects can't make sounds.  Is there a 
technical reason for this, or is it something that might be added 
later?  I used one of my joysticks for sounding the alarm when the 
WhiteRabbit was near the banana, but that led to fairly strange 
looking code: "When the WhiteRabbit is within 0.5 meters of the 
banana, have the joystick make a crashing sound." :-)

- The most complex part right now is adding objects to the world. 
The first problem is being on a Macintosh -- the collection of Alice 
objects that are available 
( use long 
filenames that don't work on Macs.  When you make an actor from 
these, you frequently have to help Alice guess the right filenames. 
The second problem is just the process of "w makeActorFrom: 
'blahblahblah.mdl'"  I had an idea of how to deal with this that I 
wanted to bounce off y'all.  What do you think about this: if 
yellow-button click on a .mdl file gave you a menu option to add the 
model as an actor in an existing Wonderland (if one is open in the 
current World), or, to open a Wonderland and stuff the actor into it? 
I gave it a shot, and the attached change set seems to do it.

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Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
Associate Professor - Learning Sciences & Technologies.
Collaborative Software Lab -
(404) 894-5618 : Fax (404) 894-0673 : guzdial at

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