Why is MESH called Mesh?

[carissabelle]

I mean i understand the meaning of the word "Mesh" but... If people are looking for things like mesh clothes, mesh fences or whatever then they would probably end up finding tons of Mesh objects, right?

I know i came upon stores that apparently offer Mesh objects when i was looking for mesh tops.

That can be confusing when people want to look for mesh/fishnet clothes on the marketplace... or am i wrong?

 

[Ceera Murakami]

Oh, it will probably cause some confusion during the transition, but once Mesh becomes a standard feature, people will slowly stop using the word as a keyword in their ads. You don't often see "sculpty" or "Prim" as clothing descriptions any more, and it's becoming far less common to see "flexi" as a distinguishing characteristic for clothes and hair.

While things change, just use other synonyms, like fishnet, netting, see-through, or whatever, instead of 'mesh' when you search for netting clothes.

[DanielRavenNest Noe]

From a 3D modeling perspective, "mesh" is the wrong terminology.  The hierarchy of models goes like this:

Vertex = a point with XYZ coordinates, and possibly other characteristics associated with it (normal direction, bone weight)

Edge = line connecting two vertices (or vertexes if you don't like Latin)

Triangle = shape consisting of 3 vertexes connected by 3 edges.  It is the simplest shape which has an area which can be textured, and thus is the nearly universal component in 3D software and graphics cards. The latter have multiple "pipelines", each of which is designed apply part of a texture to a triangle, then color it according to light sources and other settings.  That is called "shading", and the collection of settings and bit of software to apply them are called "shaders".  The collected shaded triangles from all the pipelines are gathered into a "frame", which is then sent to your monitor.

Polygon = shape consisting of 3 or more vertexes connected by the same number of edges.  Triangles are the simplest polygon, followed by 4, 5, etc sided shapes.  Polygons with more than 3 sides can be divided into component triangles.

Mesh = collection of polygons which share vertices and edges forming a connected network.  It resembles a fishing net, from which the term "network" is derived.  Since "network" is more commonly used in computing to refer to a collection of connected computers, "mesh" is used instead in computer graphics to avoid confusion.

Model = one or more meshes which are tracked as a single object by the 3D software.

Scene = file containing one or more models/objects.  Collada .dae files which we upload to Second Life contain scenes, and thus can have multiple models, which in turn can have multiple meshes for each.  If your file has multiple models, they end up as separate inventory items once loaded into Second Life.

Other terms include:

Geometry = the collection of vertex locations and list of triangles they make up, which defines the shape of a model.  Other properties (texture assignment, normal directions, bone weights) are in addition to the geometry.

So "mesh" is not the correct term for what we handle in Second Life.  We upload scene files, which contain some number of objects, which end up as inventory items.  It is as incorrect to refer to those items as a mesh as it is to refer to a prim as a "side".  Prims have some number of sides, and 3D model objects have some number of meshes, but they are not the same thing.  Unfortunately, for whatever reason, Linden Lab chose "Mesh" as the project name, and it's an uphill battle to change it at this point.

Also note the "Mesh Project" includes increasing the maximum size of objects to 64m, and graphics improvements like projected lights.  In other words, the package of software changes under the "Mesh" heading includes other features than just 3D model upload and display.  And carissabelle is correct that "mesh" is also used as a description for type of fabric or fencing so there is a bit of confusion there to be sorted out.

[carissabelle]

thanks for explaining. Well i dont think LL would change the word "Mesh" to something else lol...

 

[Runitai Linden]

We actually kicked this around a bit and settled on "Mesh" because at the core platform level, what you're uploading *is* a mesh.  In COLLADA terms, In the importer, each "geometry" node in the scene is turned into a single distinct mesh asset, and each geometry_instance in the visual_scene becomes a Second Life object that references that mesh asset.  You get a "face" or "texture entry" for each "material" entry for the "geometry" node in the COLLADA file.

You're correct that the importer is dealing with "scenes," and the "Model..." button was in fact labeled "Scene..." early in the beta, but since a "Model" is technically a collection of meshes, it's just as accurate to say "Model" and it's more obvious what the button does.  

In terms of what you get after import, it's exactly the same scene and object management as the old platform, except the geometry that makes up an individual object is pulled from a mesh asset instead of a set of primitive parameters.  Of course, the details of making that work efficiently, securely, and in a way that's scalable are what's kept us busy these past two years, but there it is in a nutshell.

So there you go, "mesh" import is what's happening, and we import "scenes" by importing lots of "meshes."  Also, we *only* support mesh import, so claiming full compatibility with COLLADA beyond meshes would be incorrect (we don't support nurbs for example).

 

 

[Vincent Nacon]

Yeah well, you guys should have gone with "polygons" as it's more proper name for 3D graphic artists.

 

Explaining mesh are not easy with graphic-clueless friends these days.

[Lee Ponzu]

My disctionary says

 

[ verb, trans. ] represent (a geometric object) as a set of finite elements for computational analysis or modeling.

[Gearsawe Stonecutter]

Easy to type and easy to say. 

[Rage Riptide]

Say it backwards and you can clear your throat.

[Vincent Nacon]

HSEM....?

The Homeland Security and Emergency Management?

 

I think I missed your joke.