[Opensim-users] Collada

[Toni Alatalo]

Dzonatas kirjoitti:
> Collada is an excellent system to collaborate on objects between 
> applications. One note to not overlook is that the 

Just a little note to make sure: that's done via the typical export & 
import -loop, with pretty big xml files too, so we are not talking about 
realtime collaboration (which was talked about here earlier when someone 
asked about Verse, which is a real-time protocol) but interoperability 
between applications by supporting a common format. Which has been of 
course a dire need which Collada (i.e. Sony..) has since a few years 
solved for some game developers at least.

> unable to directly connect a grid to each other, but they need to move 
> assets from one world to the other to get a job done. One business can 
> export all the objects to ship into a collada files. The other 
> business then imports the objects from the collada files to its world. 
> Here, the transfer of objects occurred outside of the virtual world of

When talking about OpenSim for SL compatibility, I'm unsure if Collada 
can be used at all though: does it support prims? In games there usually 
are just meshes. Well the spec does seem to support splines nicely, so 
perhaps you could reproduce prims as beziers or something. Or are they 
even for just 2d curves? I'm pretty sure it has no mechanism for 
anything like sculpties. Also it does not know about other SL specific 
asset data like permissions or scripts, but that's perhaps ok when you 
transfer modelling work that you've done.

> On that last example, to expand and simplify upon a contract I have 
> had, imagine you get a contract for a job and they hand you the 
> collada files. You then do the work locally to the files and hand back 
> the new collada files.
> The collada processor is what needs to be programmed more than the 
> import/exporter here. The processor may do more than just adjust a few 
> data types to a new type, as it may need to resolve url and combine 
> data, or it may need to separate and distribute data to various servers.
Aren't people already using the save-oar & load-oar  tools for this .. 
oh that seems to be for full regions.

Anyhow right now we are closer to having such files to save & distribute 
with the OpenSim specific xml serializing. I know Mikko Pallari in the 
Realxtend project (I'm now doing work for them too) was working on a new 
version of a serializer last week, with Adam Frisby - 
http://opensimulator.org/wiki/Xml_Objects_Format is the format sketch we 
looked at when starting the work .. Mikko showed some code last week put 
I don't know yet where he put it before leaving for holidays (am just 
catching up after the weekend myself..)

The goal in that new serializer work is to have the serialization 
independent of changes in the SOG/SOP code (i.e. how the prim/object 
groups and parts are in the internals), so that the format would not 
change with new versions of OpenSim.

As you see in that older draft already, many things in SL are totally 
different from Collada - in a Collada doc you don't see RootPosition and 
Parts, nor Shape with a Circle face and Straight Extrusion etc.

Might be still interesting to look at how things are in Collada, and how 
those Collada processors you mention work etc., but I don't see how 
Collada could work for storing SL like assets.

Verse might be able, as it is based on the notion of 'perfect data', 
like prims: a sphere is a sphere (though in Verse everything is somehow 
also a subdiv surface iirc? don't know how the details are.). And Sony 
paid Eskil a couple of years ago to write Collada support for Verse 
(import / export), as they started thinking it is perhaps the next good 
things after Collada, but that I guess is another story ;)

And of course in Realxtend where we support meshes too Collada is more 
relevant, was also discussed a while ago in 
http://groups.google.com/group/realxtend/browse_thread/thread/3c56de585b71cf91 
(the situation basically is that Rex currently supports just the ogre 
format - something more interoperable would be nice but no one is 
developing that now). But also there we'd still need something that 
support prims too, and like said that's right now going to be the new 
version of the existing OpenSim xml serialization.

~Toni

> Ralf Haifisch wrote:
>>
>> Hi there,
>>
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>> As a few maybe know, there is a 3D standard for decribing objects.
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>> http://www.collada.org/
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>> Some bigger systems use it (like google, twinity..) and if you look 
>> over their website, there are several apps that can produce collada 
>> output files.
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>> Seems to be the only standard that is industry accepted right now.
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>> The baisic idea is, to have a common format – so you are able to 
>> create content offline or export/import it, even cross-3D-platform.
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>> There is a JIRA on it, if someone thinks about Lindens side:� 
>> http://jira.secondlife.com/browse/MISC-830
>>
>>  
>>
>>  
>>
>> If you have a look at Mantis:� 
>> http://opensimulator.org/mantis/view.php?id=2827 – I was requested to 
>> search for PRO/CON and a Dev in the maillinglist.
>>
>>  
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>> So, here it is.
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>> What is you opinon on Collada implementation ?
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>> Do you think we need more a server-side (mass import) interface, or 
>> client side ?
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>>  
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>> Cheers
>>
>> Ralf
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