[Opensim-users] what version of collada is expected by various standard viewers & opensim

[Dahlia Trimble]

I'll try explaining it differently.

If you upload a single mesh then there is one asset the viewer needs to
download. If you upload several meshes, there are several that the viewer
needs to download. It doesn't matter if the meshes are the same or not, the
viewer needs to download one copy of every asset it needs to display. Since
mesh assets can be quite large compared to other network traffic, it's a
better choice to only upload *one* copy of a unique mesh and then just
duplicate it in the scene.

Each mesh object in a scene consists of a small chunk of information (asset
reference, location, orientation, texture references, etc.). The viewer
will (should) only download assets that it doesn't yet have a copy of. If
there are many chunks of grass and they all use the same mesh asset, then
the viewer only needs to download that asset once. If, however, you
uploaded a unique mesh many times, then each upload would create a new
asset and the viewer would need to download each one.



On Fri, Jul 5, 2013 at 7:07 PM, Dr Ramesh Ramloll <r.ramloll at gmail.com>wrote:

> Hi Dahlia,
> If I understand you correctly, if I upload a grass plant in mesh and
> then just multiple copy it inworld, it would not make a difference if
> made a grass patch in mesh and then uploaded it. Let me know, am kind
> of dabbling with this issue right now. Am thinking in the way for
> leaves in a tree.
> R
>
> On Fri, Jul 5, 2013 at 9:43 PM, Dahlia Trimble <dahliatrimble at gmail.com>
> wrote:
> > If an object is made up of many pieces, all of which are the same mesh,
> then
> > it would be better to upload the mesh once and just duplicate it. This is
> > because the mesh is a single asset and the viewer *should* only download
> it
> > once. However, each piece is still a single "prim" whether it's a prim, a
> > sculpt, or a mesh, and will still require a message from the sim
> > (ObjectUpdate packet) telling the viewer that it is there. This message
> is
> > quite small compared to the size of the mesh asset though and many of
> them
> > can be sent quite quickly. If the same mesh was uploaded many times and
> > these different uploads were used in the same scene, then each mesh would
> > get a different Asset ID and the viewers would have no way of knowing
> they
> > were all the same and would need to download each copy separately; this
> > could put quite a strain on the simulator and the network and should be
> > avoided.
> >
> > Note that in Second Life, "Land Impact" may be adversely influenced by
> many
> > copies of the same mesh *even though the mesh only has to be sent to each
> > viewer once*. This is an oversight in the design of Land Impact and
> > OpenSimulator does not have this issue as it does not implement Land
> Impact.
> >
> >
> > On Fri, Jul 5, 2013 at 5:49 PM, John Sheridan <john at pseudospace.net>
> wrote:
> >>
> >> re : "The various editors I tried require a lot of gymnastics just to
> get
> >>
> >> objects that render well in them to be imported into opensim.
> >> I am only familiar with ac3d, and Blender somewhat."
> >>
> >> I've been working with Blender 2.6, and while I'll admit it takes a bit
> of
> >> adjusting if you're moving from prim based modeling it works perfectly
> with
> >> opensim uploading through either Firestorm or Kokua.  Scaling is a bit
> of a
> >> headache but after upload my models show exactly as they did in Blender
> and
> >> oddly enough, they seem to actually load a bit faster.
> >>
> >> While on the topic of mesh, I did have a quick question to anyone out
> >> there regarding instancing.  Awhile back (before the advent of mesh) I
> seem
> >> to remember someone mentioning that sculpts were superior to normal
> prims as
> >> only one copy of the sculpt is downloaded and then applied to all
> objects it
> >> was used on by the viewer.  Would anyone happen to know if the same
> holds
> >> true for mesh?  Say in the case of an model with multiple duplicated
> pieces,
> >> would it make better sense to include one copy of the duplicate piece
> in the
> >> dae and then duplicate it in world or just glob it all together during
> the
> >> import?
> >>
> >> Thanks, :)
> >>
> >> - John / Orion Pseudo
> >>
> >>
> >> On 07/05/2013 08:08 PM, Nebadon Izumi wrote:
> >>>
> >>> The various editors I tried require a lot of gymnastics just to get
> >>> objects that render well in them to be imported into opensim.
> >>> I am only familiar with ac3d, and Blender somewhat.
> >>
> >>
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> >
> >
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>
> --
> '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, LinkedIn, DeepSemaphore LLC, Google+ profile
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