Difference between revisions of "Mesh/Basics"

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(Added material written by Sylvan Mole for the background to his Mesh and LOD article)
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{{:Mesh/What is mesh?}}
{{:Mesh/What is mesh?}}
==Mesh basics==
A ''mesh'' is of a collection of vertices, edges, and faces that define a 3D shape, made in an external program.
[[File:vertices black640.png|320px]]
The basic element of a mesh is a ''vertex''. Vertices represent points in space. 
[[File:edges 640.png|320px]]
''Edges'' are lines that connect two vertices.
[[File:triangle6401.png|320px]]
A ''face'' is a triangle composed of three vertices connected by edges.
[[File:Mesh Image640.png|320px]]
Together, they can combine to make models that look like this!
==File Format==
Second Life can import meshes in the COLLADA 1.4.1 (.dae) file format. COLLADA is a powerful open standard format consisting of human-readable XML.  Although Second Life uses COLLADA for importing mesh data, it internally uses a custom format for uploading, storage, and streaming of mesh content.
{{KBnote|While the COLLADA spec supports everything from polygons to nurbs, the Second Life mesh importer only imports polygonal data.  This means that you must convert your models to meshes before exporting to a COLLADA file.}}
More than you'll ever need to know about COLLADA:
* [http://en.wikipedia.org/wiki/COLLADA COLLADA on Wikipedia]
* [https://collada.org/mediawiki/index.php/COLLADA_-_Digital_Asset_and_FX_Exchange_Schema Digital Asset and FX Exchange Schema]
* [http://wiki.secondlife.com/wiki/Mesh/Mesh_Asset_Format Second Life internal mesh format spec]
Here are some examples of files in COLLADA .dae file format. [[Mesh/Sample_Content]]

Latest revision as of 03:34, 10 December 2012


Second Life has the ability to import 3D models (meshes) created in popular tools such as Maya, 3DS Max, Blender, and so on.

Why use meshes in Second Life?

Mesh models enable more detailed, complex, realistic, and creative objects and avatars. Designers can use external software tools to design avatars and other content for use inworld. Avatar designs can be joint-rigged, allowing natural-looking animation without a need for extra scripting.

What kinds of objects can be imported as a mesh?

Mesh supports models represented as COLLADA files. Many applications can create COLLADA files, or can create files that can be converted into COLLADA format. COLLADA is a very general format, so not all COLLADA files will be supported. Learn more about how to create a mesh for import to Second Life here.

Meshes may be general purpose, representing simple geometry, or rigged, in which case they also store information allowing them to be animated along with a Second Life avatar.

Getting started

To try out mesh:

  1. Go to one of all the sandboxes in Second Life. See Second Life Public Sandboxes.
    Some sandboxes may become overcrowded with Residents and have poor performance. If you see objects that look like a lot of flat triangles, try moving to another region.
  2. See what people have been working on, or try uploading some sample content of your own!

Save L$ by testing on the beta grid

Uploading mesh content to the main Second Life grid costs Linden dollars. For development and testing, upload your content to the Aditi beta grid instead. For more information about Aditi, see Preview Grid.

Follow these steps to upload models to Aditi:

  1. Import your SL account to Aditi (see Updating Your Account on Aditi for instructions).
  2. Enable the grid selection dropdown on the Second Life login screen in Me > Preferences > Advanced > Show Grid Selection or by typing CTRL+SHIFT+G.
    Note: You may need to enable the Advanced menu by pressing Ctrl+Shift+D
  3. In grid selection, choose the Aditi beta grid.
  4. Your account on the beta grid has its own L$ balance, so Linden dollars earned and spent on Aditi do not affect your main grid L$ balance.

Brief demo and introduction to mesh

<videoflash type="youtube">TlIn35BuNfU|448|353</videoflash>

Mesh glossary

  • Mesh - A collection of triangles with a single transformation matrix, roughly equivalent to a "Prim" in SL.
  • Submesh - A subset of a mesh, equivalent to a "Face" on a normal prim. Associated with a texture entry.
  • Model - A mesh or collection of meshes, equivalent to a "Coalesced Object".
  • Aditi - The Second Life beta grid, where you can test new features and ideas, such as mesh upload, without risk to any of your Second Life assets. For more information, see Preview Grid.
  • Land impact - Mesh objects are equivalent to one or more traditional second life prims. For information on prim equivalence, see Calculating land impact.

Types of meshes

A simple mesh is a mesh with a single face. It has a single color and texture, and can model a simple object in the real world.

A multi-face mesh is a mesh with multiple textures.

A rigged mesh is a mesh with an internal virtual skeleton. Manipulating the virtual skeleton causes corresponding changes in the shape of the mesh, which allows the mesh to be animated.

Get started

Try uploading your first mesh model to Second Life! See Uploading a mesh model to get started.