Subject: Re: [mmox] rezzme URI scheme: addressing locations/grids (SLURLs are bad, bad, bad)

From: Cenji Neutra <[email-masked]>
Date: Fri, 6 Feb 2009 15:24:57 -0500

It seems unlikely to me that virtual world implementations of the
(moderate) future will include any fixed 1-1 correspondence between
named locations used by people and particular geographically
distributed simulation processes (if they do, they'll soon give way to
the more computationally efficient implementations of their
competitors).

I think we all know that LLs decision to expose an implementation
detail like sims/regions (which correspond to a process responsible
for simulating a fixed-size geographic area and the physical objects
within it) in the user interface of SL as named regions, was motivated
by the trade-off between generality for the future vs expedience and
simplicity of development / time-to-market.

So, the question is, does a location addressing scheme like
(region-name,x,y,z) even belong in such a forward-looking standard?
While any virtual world that employs a 2D land-area can have such an
addressing scheme overlaid on it, I would think it isn't appropriate
to include it at such a low level as to force other implementations
into using such a scheme.  There exist implementations for which
simulation resources are distributed dynamically over the entities
that need to be simulated, rather than fixed geographic areas - as in
SL, and for which a such a mapping may not be practical to implement
or desirable.

Obviously, the standards process has to agree on some basic properties
of what constitutes the X in MMOX.  Is that going to imply some
simulated 3D space?  If so, perhaps a global x,y,z is all that is
needed (and vendors can map vendor-centric schemes over that if
desired).  If not, and the 'space' is not constrained to physical
space analogues at all, then perhaps dictating 'location' addressing
schemes is outside the scope? (for example, an application agent space
where agents move according to the interaction patterns dictated by
the application logic wouldn't fit into a geographic scheme well)

My personal preference would be that we limit the scope of the X in
MMOX to systems that simulate some analogue of 3D physical space (not
necessarily continuous or simply-connected).  That way, if location
addressing is within the scope, something like a global x,y,z can be
used and then vendors can easily map other schemes over that (or not)
as desired.

-David

SL: Cenji Neutra
--
Apez - we make your virtual life easier
http://www.apez.biz

> Date: Fri, 06 Feb 2009 13:05:11 +0100
> From: Dr Scofield <[email-masked]>
> Subject: [mmox] rezzme URI scheme: addressing locations/grids (SLURLs
>        are bad, bad, bad)
> To: [email-masked]
> Message-ID: <[email-masked]>
> Content-Type: text/plain; charset=ISO-8859-15
>
> i think we need a virtual world independent way of addressing locations
> in virtual worlds. Linden Labs did coin the SLURL way of doing this for
> the linden lab grid --- unfortunately SLURLs don't allow us to address
> locations on other grids, let alone other virtual world platforms (e.g.,
> OpenSim grids).
>
> we'd like to propose the rezzme:// URI scheme
> (http://xyzzyxyzzy.net/2009/01/07/addressing-places-in-virtual-worldsor-why-slurls-are-bad/)
> --- a reference implementation of a rezzme protocol handler is available
> (http://forge.opensimulator.org/gf/project/rezzme/).
>
> we've been using it to address OpenSim grids, Linden Lab main and beta
> (and other) grids. the rezzme protocol handler utilizes GridInfo.
>
>    dirk
>
> --
> dr dirk husemann ---- virtual worlds research ---- ibm zurich research lab
> SL: dr scofield ---- [email-masked] ---- http://xyzzyxyzzy.net/
> RL: [email-masked] - +41 44 724 8573 - http://www.zurich.ibm.com/~hud/
>

---

From: Morgaine Dinova <[email-masked]>
Date: Sat, 7 Feb 2009 08:18:30 +0000

> used and then vendors can easily map other schemes over that (or not)

I think that it would be very bad to exclude 2D worlds, Cenji.  There is no
good reason to place a lower limit on the dimensionality of virtual worlds,
nor an upper limit.  Indeed, 2D scrollers are still very popular, and have
no less a right to addressing support without being treated as a degenerate
case.

Likewise, higher-dimensioned spaces may well appear --- we're already
mapping a 3D scene onto a 2D screen after all, and a 4D timespace world in
which time is also addressable and navigateable is easily envisaged, as are
hyperspace worlds.  I don't think that we should impose any arbitrary
restrictions on addressibility.

An address makes sense only in the context of a specific world, and
therefore it is misguided to attempt to straightjacket all worlds into a
single format.  Indeed, SL already employs 4 dimensions of addressibility in
its live world, namely {region, a, y, z}, or 5 dimensions when you add
{gridname} to account for its special-purpose grids such as the Teen Grid,
Preview Grid, OGP Beta Grid, and so on.  Therefore I suggest that addresses
simply be tuples with an arbitrary number of terms, and that the number of
terms and their types should be entirely a matter for the world in question,
and nobody else.

Morgaine.