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

[John Sheridan]

Dr. Ramloll,

You would probably get a better benefit if you were to upload a few 
different variations.  For example: a single plant, a 10x10 patch of 
joined plants, a 20x20 patch, and so on.  Each of the three variations 
if duplicated in world would only be downloaded once and you would have 
the flexibility to cover a variety of different areas in different sizes 
more efficiently.

In regard to prim counts, if you were to upload a single plant and then 
build your patch in world you would likely be using far more prims than 
you would if you uploaded a pre-joined patch.  So, not counting for 
vertex counts and all the other goodies that come from a land impact 
calculation - the following would hold true.

1 plant    = 1 prim     = 1 mesh download, 1 object download
10 plants (linked in world) = 10 prims = 1 mesh download, 10 object 
downloads
10 linked plant patches = 100 prims = 1 mesh download, 100 object downloads
1 patch (10 plants joined in mesh before import) = 1 prim = 1 mesh 
download, 1 object download
10 mesh patches = 10 prims = 1 mesh download, 10 object downloads

The theory being that the mesh download is much larger than the object 
download.  The mesh download contains the mesh's geometry, textures, 
texture maps, and so on wherein the object download contains such things 
as the object's position in world, the id of the mesh, textures, and so 
on that are applied to it.

I hope this helps.  :)

  - John / Orion Pseudo

On 07/05/2013 10:07 PM, Dr Ramesh Ramloll 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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