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David Faught
Hans N. Beck wrote:
>Just for interest: is there a certain team working on navigation
>concepts (for moving, searching and orientation), for example at
>any university or some potential member of the comming
>consortium, or in form of a spectial (sub-) project, or is it
>more a matter of the main croquet development team ?

I am a member of the public Croquet community, not any part of the main development team nor any of the supporting university teams, so my information is limited.

<rant>It has been stated a few times in different places that, right now, the core teams want to spend their time concentrating on getting the bugs shaken out of the next much-anticipated Hedgehog version of Croquet, so that it can be released.  I am very surprised that a couple of them have taken the time to participate in this thread.  In fact, shame on them (shaking finger in their general direction), get back to work!  I know that they are very interested in discussions like this, and once the new version is released and most of the bugs are squashed, I'm sure that they will have a bit more time to participate.</rant>

The only clue that I can find about your question is on the Croquet RoadMap, which is somewhat out of date.  On the Roadmap, there is an item that talks about Navigational Control.  The way that it is described leads me to believe that it is completed (in Hedgehog), but does not really address the range of navigation services that you are interested in.

The Croquet RoadMap is at:

Other members of the community have worked on some aspects of the navigation services you described:

Dave Faught wrote:

>Hans N. Beck wrote:
>>So in all cases, we have to deal with positions. And how are
>>they defined exactly ? A mathematican would use a free defined
>>but then fixed coordinate system. A child would say "next to the
>>place where I go to school" or "first I go around this and along
>>there and there it is". Cats would reference it's accoustic
>>picture in mind. For convinience I would call these methods
>>a) geometrical (y=f(x,y,z...))
>>b) topological (next to...)
>>c) behavoural (move here, then go right....)
>>d) pattern matching (the cats acoustic picture)
>>navigation methods.
>Although, it may be implied in your description, it is important >to also talk about orientation, or heading, in addition to just >position. Orientation also has these different frames of >reference.

Thinking back, I have used portions of 3 out of 4 of these navigation methods in projects for Croquet Jasmine.  These projects are available on SqueakMap at

In the MockTurtle project, there is the behavioral method, implemented as turtle graphics commands.  In the Croquet-alife project, there is the topological method, at least partially.  The objects have goals like "move towards your brothers, and stay away from predators."  The geometrical method is used explicitly by both of these projects for initial positioning.

All of this is done in Smalltalk/Squeak/Croquet code, with no particular input from the user.  So, for me, one of the interesting parts is how to make these methods available to a user for directly manipulating and scripting scene objects.  There are at least a couple of different approaches to this.

I'm sure that there are other examples of these navigation methods in other Croquet Jasmine projects.