[Opensim-dev] robot simulation

Sun Mar 2 04:06:28 UTC 2008

On Sun, Mar 2, 2008 at 11:40 AM, Diva Canto <diva at metaverseink.com> wrote:

>  ouch, my comment sounded a lot more judgmental than I intended. There's
> really nothing wrong with sex beds and gorean warlords :-)
>
> As far as I know, there is no simulation environment that is both accurate
> in terms of physics modeling, and affordable and social at the same time. An
> environment like that would be a major enabler for lots of cool stuff -- the
> word used these day is "transformative". I'm also thinking of
> special-purpose, not necessarily affordable, clients for it like the "cave"
> down at UCSD, a fully immersive 3D environment where you can physically move
> around the objects, using special goggles -- it's such an intense feeling!
> Just imagine the wonders that that would do for real world systems
> engineering! (ok, and for sexual and warlordy fantasies too, but you don't
> need good physics for those :-)
>

Imagine a world where entities are not controlled but programmed. In C#,
lsl, etc. You get sensor data and you have to make your entity or entities
win and conquer others.
Physics and sensors information can open unimaginable new possibilities.

What bothers me more is that I don't know (I have to admit I have only taken
a brief view to the code) how much experimentation can be done without
modifying the client to test it.
And it seems that openviewer still have a long road ahead.

About emulating physics instead of simulating physics. That can work for a
set of applications. Let's say we emulate weight by assigning a mass
property to the objects and our entity has a script that makes it not be
able to carry heavy objects, etc. It may work but surely different kind of
worlds will have different needs so other script has to be develop and other
and other ...
A physics engine though not being magic (you'll have to tune it for every
world) is the most general solution I can think of.

The project I collaborate to have currently physics, rigid objects, joints,
movement controllers, sensors, etc. If I am able to "librarize" it, we can
use it as we may use a physics engine library. I still have to take a closer
look to the architecture of opensim to see if it is possible but it may be
an option.

The first issue I can think of is that not only animation based movement
(not controlled by physics) but articulated based movement (controlled by
physics) will be used. Maybe the physics based movement can be translated to
animation based movement for SL compatibility.

The second issue is that using Collada can be a good idea (physics and
visual information in the same format), the ogrecollada project is very
active now (openviewer will use Ogre3d, right?) and I am going to add
collada physics support to mine soon also. I don't know how can this be
mixed with current SL mesh format.

Doing that work in a separated branch will not be needed if it can be
modularized away (right thing to do, don't know how difficult it can
become).

I'd like to know more comments from people knowing the code and
architecture.

>
> The sophisticated modeling tools used at NASA, Boeing, etc don't have the
> affordability and social parts. The ones that do -- and I know of early
> experiments there using Active Worlds -- aren't that accurate for the
> physics part. So we're talking about pushing the boundaries here, sci-fi
> stuff, really. It's not easy to do; it's not obvious at all how to do it,
> for the concrete reasons already mentioned.
>
> The good thing about OpenSim and libsecondlife is that they're open
> source, so there's the opportunity to make side experiments that diverge
> from the main track, as long as there are motivated people to do it. I'm
> sure whatever is learnt in the process will be of enormous value, even if
> the actual code is thrown away and rewritten 1 year later so that the ideas
> can be merged. This process of experimentation is usually done in
> universities, but I see no reason for it not to happen in a project like
> this, with highly motivated, highly skilled part-time people. Those people
> just have to keep in mind that they're still experimenting, and not get
> frustrated that their code is not being integrated right away. So, a
> parallel project sounds really good!
>
>
> dan miller wrote:
>
>  WRT to SL being a "game" platform, therefore using physics for added
> realism but not for function: that may be true of Linden Lab's SL. I
> hope the people here in OpenSim break away from that whole "fantasy
> game" philosophy. Some fantasies -- social, technical and scientific --
> end up having a huge positive impact in the real world. Those are a lot
> more worthwhile supporting than sex beds and warrior tales (not that
> there's anything wrong with that, but ... choose your game!)
>
>
>  Ditto and Amen to that.
>
> If we can get a quorum of developers interested in this, I'd love to get our
> own IRC channel (opensim-physics?)
>
> I think I was a bit cup-half-empty with jordi last night.  I want to
> reiterate that what he wants to do is very much something that I feel
> Opensim should *eventually* support.  My concern is really just the state of
> the code, and the fact that I know from experience that most of the core
> developers are much more concerned with getting the underlying architecture
> together than in worrying about the subtleties of physics and simulation.
>
> I almost hate to suggest this, but it may be the case that some sort of
> development branch focusing on more sophisticated physics would be in order.
>  I've found that the constant flux of development at the db and
> client/server layers makes it rather difficult to try anything radical -- by
> the time you have something interesting going, you have a big hurdle in
> merging it back into trunk without mucking up something people are depending
> on.  This forces physics development to be rather conservative.  Teravus and
> others are doing great work, don't get me wrong -- but they are basically
> just trying to add SL-compatible features, and keeping current with the rest
> of the team.  There may be room for a more speculative branch of
> development, that isn't worried about grid mode or inventory, but just
> focuses on how the physics layer actually works, and how it could be
> improved.
>
> Just a random 2.5 cents
>
> -danx0r
>
>
>
>
>
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>

-- 
Jordi Polo Carres
NLP laboratory - NAIST
http://www.bahasara.org
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