[Fiware-miwi] App architecture sketch

[Toni Alatalo]

Thanks, we checked this quickly with Erno here and have a few questions:

First, is the server implementation open source and, if yes, where is it?

Then some points about the entity model and VW functionality:

You have apparently kind of hardcoded the concept of the avatar, tied login information so some 3d positioned entity etc. This is something that we were very happy to *remove* in realXtend when switched away from LLUDP and Opensimulator. In Tundra the client connection information is in the UserConnection object and it's up for the application logic to decide whether and how user presences show in the ui / scene. I think we want to keep that. For example in a SimCity like scenario the users don't necessarily have any 3d presence at all even though they are all collaborating in the same 3d scene. Also when making e.g. a chat + whiteboard application without a 3d scene it's weird that the platform would insist putting some 3d position for the presences. Of course if the scope of FiVES is only for certain kind of applications, and not a more generic platform like with Tundra, this can make sense (I  don't really know what FiVES is, only a glance from quick search). This is supposing that the Avatar plugin in your doc is considered a 'core plugin', and it would seem so as ClientManager depends on it.

Likewise in the messaging there are avatar specific messages etc. There we've resorted to generic attribute manipulation and entity-action triggering calls, not having application specific things in the platform. Perhaps I am reading this the wrong way -- KIARA being the generic application agnostic layer, whereas Fives is like one application (some system with avatars)? This probably also shows how we don't know what your effort is and how it is perhaps related to FI-WARE..

Also,  we were curious about the rationale for separating the scenenode matrix to position, orientation and scale components. I'm not really criticizing that (yet :) but trying to understand. Usually it's a single 4x4 matrix in the end anyways so has seemed straightforward to handle as such in many places -- though in networking it is often handled with more granularity, perhaps net message optimisation is your motivation as well? Anyhow it seems a bit strange at first in the entity model that something could have an orientation without a position, or a position without scale .. I suppose then you'd default to 0 position and 1 scale etc? What happens for a piece of code that encounters a positioned object and tries to read it's scale - it gets the default value if the scale component doesn't exist? Or no value is returned, as the component doesn't exist? But the rendering uses the default value of 1 so it looks like the component existed? That would be confusing I think.

For editing I'm not sure if the 'Location, Renderable' dependencies are necessarily - in Tundra we are used to having non-position so-called application entities which only have a script component. We can edit those (the script reference and parameters) over the wire without those entities being placable nor renderable. Your script component seems similar to realXtend's so perhaps the same logic for editing would apply, or do you mean something else with it?

Cheers and thanks for sharing,
~Toni

On Sep 23, 2013, at 3:44 PM, Torsten Spieldenner <torsten.spieldenner at dfki.de> wrote:

> Hello,
> 
> a first, very high level overview of FiVES Entity-Component-Model, list of Components, Plugins and the KIARA Interface for Server-Client-Synchronization are now available at
> 
> https://forge.fi-ware.eu/plugins/mediawiki/wiki/miwi/index.php/Current_FiVES_implementation_details
> 
> Please note that the interface is still under design, and there will be slight changes to the existing Plugins / synchronisation functions, and new ones are very likely to come during the next days.
> The client will then support rendering of entities by referenced XML3D mesh resources, as well as users that are represented as avatars, including a very basic user authentication.
> 
> ~ Torsten
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