alice-teacher Alice 3.1

[Don Slater]

These are good questions / comments, I am sure shared by many people. Let me see if I can briefly address them, and perhaps we will be able to better explain in the coming weeks…

See below:

On Aug 15, 2012, at 11:55 AM, "Gamez, Enrique A (172B)" <enrique.a.gamez at jpl.nasa.gov> wrote:

> I read that the Alice 2.x and 3.x series are both being maintained, not merely to help in a transition but they're being targeted at different levels of students.  I'd like to understand a bit more about this decision.  You obviously have limited resources to maintain a free product like this and I'd rather see you guys put all your eggs in v3 so that we can be assured timely updates and improved features.  Even a company like Apple stops supporting previous versions of their software.

Alice 2.x and Alice 3.x are supported by some of the same funding streams, but there are also different funding streams for both projects, and our responsibilities to those sources of funding require maintenance of both projects. More importantly, our user base requires the maintenance of both projects. There clearly are two different audiences for the Alice Suite, with at least two, and in reality, many, uses and desired outcomes for the courses in which Alice is being used.

One of the biggest sustaining forces for keeping Alice 2 is the curricular resources that are available for Alice 2, both text books and instructor materials, at aliceprogramming.net and the repository at Duke University, maintained by Dr. Susan Rodger.

Our original thinking was that Alice 3 would be a replacement for Alice 2, but that thinking has evolved as we have come to better recognize how and for what purposes people are using Alice. Like a Swiss army knife, Alice could be designed to do a lot of things, pretty well, but then we fell it would not do anything very well. MS Word could be used to generate acceptable presentations, but it would not serve this purpose as well as PowerPoint. They are different tools for different purposes, and at this time we see Alice 2 and Alice 3 in the same way. It is a problem that we recognize the number implies the second will supersede the first.

Perhaps it would be helpful to remember that Algebra 2 does not replace Algebra 1.

In terms of our allocation of resources, we are devoting almost all of our resources to Alice 3. Alice 2 is primarily in support mode. We are supplying bug fixes, and providing limited feature development and implementation, responding primarily to strong demands from our user base (for example, our rapid growth around the world has spurred our work in developing the Spanish version. Incidentally, much of the labor-intensive work in developing the Spanish version, the relabeling of the gallery has been done on a volunteer basis, by our partners in Costa Rica.) Other languages are coming.

We do have some crossover work being done in model building. There has been a demand for new models for Alice 2, and the models being built there are being designed so that they can be brought into Alice 3.

Alice 2 will be with us for th foreseeable future. There may be a time when it is replaced by Alice 3. But realistically, when it is replaced, it will probably be by Looking Glass, a tool being developed by our partners at Washington University, St. Louis. (You may look at this tool by visiting http://lookingglass.wustl.edu.)

> 
> On differentiating the two versions:  all I read is that there are configuration parameters available in 3.x (I have yet to install it) that are appropriate for older learners.  Does this mean that if we don't enable these special parms the 3.x series will be appropriate for younger learners?

We are still working on preference settings that allow people to use Alice 3 as they would in Alice 2. We are close, but we do not have it "nailed" yet, at least to our satisfaction. I implied above that Alice 3 could be used reasonably well in an Alice 2-style course. I think the biggest impediment is the lack of instructional materials. But Alice 3 is aggressively object-oriented, where Alice 2 is object based, which creates some difficulties for younger learners, an students in a general introduction to programming fundamentals that does not wish to be very "object-oriented".

> 
> On compatibility:  can "worlds" created with 2.x be opened with the 3.x product?  If not, is there a conversion utility in the works or available?  Will there be a "was : is" chart for those wanting to port their creations to Alice 3.x?

Alice 3.1 models are significantly restructured. This restructuring involved the development of a consistent skeletal hierarchy for each superclass in the gallery (Biped, Quadruped, Flyer, Swimmer, Prop).  The restructuring allows for a class hierarchy that supports inheritance to a greater degree than in Alice 2. (Note that introductory students do not need this feature but more advanced student do.)
 
The design of Alice 3 gallery models is joints-based (rather than the subparts-base used in Alice 2). Creating animations using components of an object now involves manipulation of the joints of the object instead of the sub-parts of the object. This may seem to be a subtle change, but it allows the use of a soft-skin for the models, creating more realistic animations when a component of a model is animated. For example, an object kicking its leg outward will no longer move outside its clothing, exposing a bare leg.  

This redesign of the gallery means that worlds created in Alice2.x, and worlds created in AliceBeta 3.0, will not be able to be imported into Alice 3.1. The models are fundamentally different, and there is no conversion utility currently planned that would support such a conversion.

Part of this is also aesthetic. The Alice 3 environment models are richer and more complex, and the Alice 2 models will suffer in comparison.

We are creating a pathway in which people will be able to create their own 3D objects created in other tools, and import them into Alice, using the skeletal structure and guidelines we will provide.

I will soon be publishing a document that more specifically outlines the differences between Alice 2.x (and AliceBeta 3.0), and Alice 3.1

I hope that this helps.

All the best,
Don Slater
 


> 
> Thank you,
> -enrique
> 
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