[Opensim-users] Opensim nooby question on UUIDs

[Justin Clark-Casey]

Just to add to what Dahlia said, by default baked avatar textures are treated as temporary - they are not stored 
permanently.

However, osAgentSaveAppearance() and osNpcSaveAppearance() will convert these temporary textures to permanent ones so 
the UUIDs will always successfully located them.

The OARs later save these textures when they scan the appearance notecards for valid asset UUID references.

On import of that OAR, the NPC baked textures will be inserted into the database if necessary with the same UUIDs. 
Therefore, a later NPC rez will use the data saved in the appearance notecard to retrieve the correct textures.

On 06/05/13 02:13, Dr Ramesh Ramloll wrote:
> Thanks Dahlia for replying (on a Sunday night). This clears things a bit for me. I was wondering if oars also contains
> UUIDs for those stuff that need permanent UUIDs. Or are they regenerated, during import into a completely different
> install of opensim?
> Thanks again.
> R
>
>
> On Sun, May 5, 2013 at 7:48 PM, Dahlia Trimble <dahliatrimble at gmail.com <mailto:dahliatrimble at gmail.com>> wrote:
>
>     UUIDs can be temporary or permanent depending on what they are used for. In general they are used wherever a unique
>     key is needed for accessing some other data. Assets such as textures or notecards are assigned permanent UUIDs, and
>     temporary assets such as avatar baked textures get temporary UUIDs. UUIDs are used pervasively throughout
>     OpenSimulator and are usually assigned by a random number generator. It's generally believed that the probability of
>     2 randomly generated UUIDs not being unique is so small that it will essentually never occur (UUIDs are essentially
>     128 bit integers) so they can be used freely without risk. Of course this all depends on the quality of the random
>     number generator used to generate the UUIDs ;)
>
>     There are also cases where UUIDs can be generated by a hashing algorithm. Usually in such cases this is used to
>     detect and prevent duplicate data being stored, i.e., if several people upload the same texture, then only one copy
>     of the texture need exist in an asset server that uses such a hashing scheme.
>
>
>     On Sun, May 5, 2013 at 3:53 PM, Dr Ramesh Ramloll <r.ramloll at gmail.com <mailto:r.ramloll at gmail.com>> wrote:
>
>         Hello,
>         I understand that the UUID are unique only with respect to a given session of the sim. Correct me if I am wrong.
>         So UUIDs change, this can be tested trivially.
>         But how do notecards save avatar appearance? This would suggest the UUIDs of clothes or attachments would not
>         change across sessions. So am a bit confused about how notecard data containing UUID pointers still work in a
>         different session.
>         Thanks
>         Ramesh
>
>         --
>         'Consider how the lilies grow. They do not labor or spin.'
>         *Rameshsharma Ramloll* PhD, CEO CTO DeepSemaphore LLC, Affiliate /Research Associate Professor/, Idaho State
>         University, Pocatello, ID 83209 Tel: 208-240-0040 <tel:208-240-0040>
>         Blog <http://deepsemaphore.posterous.com/>, LinkedIn <http://www.linkedin.com/in/rameshramloll>, DeepSemaphore
>         LLC <http://www.deepsemaphore.com>, Google+ profile <https://plus.google.com/103652369558830540272/about>
>
>         _______________________________________________
>         Opensim-users mailing list
>         Opensim-users at lists.berlios.de <mailto:Opensim-users at lists.berlios.de>
>         https://lists.berlios.de/mailman/listinfo/opensim-users
>
>
>
>     _______________________________________________
>     Opensim-users mailing list
>     Opensim-users at lists.berlios.de <mailto:Opensim-users at lists.berlios.de>
>     https://lists.berlios.de/mailman/listinfo/opensim-users
>
>
>
>
> --
> 'Consider how the lilies grow. They do not labor or spin.'
> *Rameshsharma Ramloll* PhD, CEO CTO DeepSemaphore LLC, Affiliate /Research Associate Professor/, Idaho State University,
> Pocatello, ID 83209 Tel: 208-240-0040
> Blog <http://deepsemaphore.posterous.com/>, LinkedIn <http://www.linkedin.com/in/rameshramloll>, DeepSemaphore LLC
> <http://www.deepsemaphore.com>, Google+ profile <https://plus.google.com/103652369558830540272/about>
>
>
> _______________________________________________
> Opensim-users mailing list
> Opensim-users at lists.berlios.de
> https://lists.berlios.de/mailman/listinfo/opensim-users
>


-- 
Justin Clark-Casey (justincc)
OSVW Consulting
http://justincc.org
http://twitter.com/justincc