[Opensim-users] Collada

[Dzonatas]

Toni Alatalo wrote:
> 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.
>   

We aren't talking here about replacing the the network protocol that now 
exists in the the sims with Verse.

> 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.
>
>   

All that can be placed in the collada file, which is XML. What matters 
is that the DOM interface recognizes the data. The collada teams has 
sorted out popular formats into the format, and we can add more data 
types, like group information and permissions. You aren't limited by 
what the collada team has only sorted. Yes, it can all be put into the 
collada file.



> 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.
>   
Parametric prim data can be placed in a collada file as well.

> 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
>   


Collada is designed to be an intermediate language. What CIL in 
.NET/Mono is to various languages, like C/C++/C#/J/Java/etc, is 
analogous to what Collada in 3D graphics is to various 3D applications, 
3DS/SL Viewer/OpenGL/and everyone else listed here: 
https://collada.org/mediawiki/index.php/Portal:Products_directory

When the optimized, xml-serialization format is determined, then it 
would be good time to see how to rearrange that again into collada format.