Jump to content

WHAT IS A MESH? WHY DO I NEED IT?


Morgaine Christensen
 Share

You are about to reply to a thread that has been inactive for 4118 days.

Please take a moment to consider if this thread is worth bumping.

Recommended Posts

I am a hobbiest builder, who sells a few things from time to time only recently started using sculpties in my builds.  I like SL and stay in SL because I can create things.  I cannot make sculpties, albeit not for the lack of trying. Blender and Wings are alien beings that make me run screaming.

What are meshes?  Why do we need mesh?  I have no clue what meshes are other than some intricate sclulpty.  Sounds to me like you have to be someone with alot of knowledge to make them.  What good it is going to do me or other builders contributing to the SL Economy other than I have to purchase more expensive components to incorporate in my build, or, I have to quit buiding period? 

I don't mind improvements, but for the masses they could of improved the in-world building tools rather than something that requires a specialized program with specialized skills. I don't mind learning new things I have learned fledgingly how to use Photoshop because of SL, but blender and wings just elude me....the concept eludes me.

Is there an URL for basic  basic basic concepts and explanations for clueless new folks?

 

Link to comment
Share on other sites

A mesh is the... well... mesh, with faces, edges, vertices that everything in SL is made of. The sculpties you make are meshes in your 3d modeling program, but you have to upload them into SL as images. Mesh you will be able to upload as a finished model. Sculpties have very specific rules they have to follow to be usable, but mesh allows you to work more freely as you model, adding or deleting faces, creating holes in the mesh, texture in a more standard way (for 3d modelling) using your own UV-maps. The sculptie is being applied to a prim inworld, defining the position of the vertices of that particular mesh. Mesh models do not have to be translated in the same way since they are already models.

Hopefully this makes some sort of sense... :)

- Luc -

Link to comment
Share on other sites

You will need a lot of knowledge to make them.

You'll have to get good at 3D modelling apps.

Things like Blender, Maya, 3ds Max, Carrara, Hexagon, and so on.

Mesh for SL means being able to import 3D models. It'll probably kill the architecture built with prims market pretty quick. Mesh is ideal for static objects. I suspect it will be a blessing for vehicle makers too.

But I suspect it will have trouble taking over fashion do to there being no consistent shape among everyone (and there shouldn't be - even if we could agree on scale for our avatars, some people are thin, some fast, some athletic, some sleek, some Asian, some White, some Black, some Native American, etc...

Accessories though will likely go to mesh quickly. Sooner than clothing anyway. Jewerly, shoes, handbags, hats, glasses - that sort of thing.

 

Link to comment
Share on other sites

SL prim building techniques will continue to be just as useful after mesh is introduced as they have ever been, though mesh will allow you to do some things that have never been possible before. For example, you can make a mesh bend with your avatar's joints.

You can make 3D models for mesh yourself using a 3D modeling program, or buy them from others. Mesh will make more existing 3D models usable in-world, and it is more capable and has fewer limitations than sculpties do. I also find that more 3D modeling techniques are usable for making meshes than for making sculpties.

I'm not sure it's practical to improve in-world prim tools to the point that where can make complex models without making in-world building as hard to learn as 3D modeling programs are. Basic building using prims has always been a great way for people with no modeling experience to begin making things, and many of us who started that way have gone on to learn more advanced modeling.

Look at SL as a good excuse to spend your time learning blender or the other 3D software of your choice. Like all worthwhile things, it takes time and effort. Mesh support makes the effort you put into learning 3D modeling more useful.

http://wiki.secondlife.com/wiki/Mesh

Link to comment
Share on other sites

It'v very easy for those who know the software to make mesh building components. I would expect that market to be very competitive and thus inexpensive. I would be surprised if there were not a lot of free ones quite quickly. With any luck, your building will become more interesting with these. There will also still be plenty of harder higher end higher quality stuff where mesh makers can find their market.

Link to comment
Share on other sites

- What are meshes?

Type Ctrl-Shift-R in any SL viewer.  Every 3D program, including SL, uses triangles to define the shape of objects you see.  In wireframe mode, which Ctrl-Shift-R toggles, you are not applying the textures as it normally does, and you only see the "skeleton" of the shapes.  A mesh is simply a set of triangles that are connected by sharing edges.  For example, the avatar body is a mesh, as is the terrain geometry, and the sky.  Prims are pre-defined meshes whose shape you can edit directly in the viewer (rez a prim in wireframe, and edit it's shape, and you will see that).

- Why do we need mesh?

It allows us to upload custom shapes, instead of being limited to the default prim set. Prims always have all their geometry, even if you cannot see it.  A mesh version of an object can leave out the parts you don't see.  Compared to a sculpt, which has a fixed number of corners defined by the sculpt map size, you can use just as many as you actually need.  So a mesh object can be more efficient than either a prim or sculpt.

Prims and sculpts have a fixed number of surfaces (sides) that you can texture indepenent of each other.  A mesh can have a custom number of surfaces with a custom layout.  So overall you have more design freedom.

3D modeling is a marketable skill in the real world, besides making stuff for SL.

- Learning to make them

If you build in SL, you are familiar with the colored movement arrows and scaling a prim, and linking prims to make a linkset.  Well, most 3D programs start with the very same kinds of primitive shapes that SL uses (box, cylinder, sphere), but in addition to moving the entire shape, you can choose individual sides, edges, or corners and move them around.  You can also add or remove parts of the shape, and connect prims to make more complex objects.  The apparent complexity of some 3D programs comes from having lots and lots of ways to modify shapes, but you don't have to use them all.  I use about 10% of the functions in 3ds Max.

Once you have the shape the way you want it, the next step is how your textures will be applied to it's surface.  That process is called "UV mapping", and simply defines which part of the texture goes where.  Then it's matter of saving the file and uploading to SL.  So for any 3D program, you need to learn 3 basic things: how to modify the shape, how to do the UV map, and how to save and upload to SL.  The details will vary from program to program, but fortunately most of them have tutorials online.

- Inworld tools

We have asked for an in-world editor for mesh shapes, but that is not part of this first mesh release.  In fact, it is SL that is specialized with it's prim building system.  Most every other world, game, or computer graphics project uses triangulated meshes and the tools to make them. 

- Some basic concept links:

http://people.csail.mit.edu/fredo/ArtAndScienceOfDepiction/1_Introduction/reviewGraphics.pdf

http://softimage.wiki.softimage.com/xsidocs/poly_basic_PolygonMeshes.htm#Rca45191

Link to comment
Share on other sites

Here's a couple of sites that explain the theory of modeling:

Guerrilla CG - http://www.youtube.com/user/GuerrillaCG
An overall 3D primer in video form. These 13 or so short videos make the basic concepts easy to understand.

Modeling Ethic: Preface
This is a good overall 3D primer in text format. It goes a little more in depth than the above videos. 

 

Link to comment
Share on other sites


Luc Starsider wrote:


Vivienne Schell wrote:

WHAT IS A MESH? WHY DO I NEED IT?

 

It is a stone aged 3D modelling format. And you need it cause the Linden Lords said so.

Huh? stone aged 3D modeling format??? Could you elaborate a bit on that?

- Luc -

SL is using COLLADA 1.4, that is from 2006. o.O

Link to comment
Share on other sites

"SL is using COLLADA 1.4, that is from 2006. o.O"

Is it? And how do you create Collada?

As far as i know 3Ds, the standard for "mesh" creation, was released in the 1980´s.

Oh, and the first 3D game using "meshes" (inclusive engine) was released in the eaarly 1990s.

/me yawns.

It´s longer than the beard of Slartibartfast, folks. Much longer.

Link to comment
Share on other sites

Luc, she does not have a good answer, because she is only here to troll and complain.

The fact is 3ds Max 2012, which was released a whole month ago, still has "Standard Primitives" ie prims, like box, cylinder, and sphere.  Why? Because they are useful starting points to model things.  You can convert them to editable polygon meshes and work on things in more detail afterwards.

The Collaborative Design Activity (Collada) is an XML schema to exchage 3D model data.  Saying it is young or old is as silly as saying jpeg image format is young or old.  It's age doesn't matter, it's how many different programs use it so they can exchange files.

A triangle is the simplest shape with an area you can texture.  Graphics cards have multiple pipelines that do nothing but apply lighting and textures to triangles, very very fast.  Those are matters of geometry and hardware.  Therefore graphics software (Second Life, 3ds Max, and most everything else) is written to use triangles as the basic element to make 3D objects from.  A polygon mesh is merely a collection of triangles which share edges.

There are ways to describe the shape of an object with a few numbers (parametric) or some formulas (procedural), but when it comes time to put an image on the screen, the graphics card still only knows how to work with triangles.  So those parametric or procedural models get converted to meshes somewhere along the way.

So Vivienne saying "meshes" are old is just as foolish as saying the alphabet is old.  So what?  As long we humans all read the same alphabet, and graphics hardware all read triangle meshes, they will be continue to be used.

Link to comment
Share on other sites


Vivienne Schell wrote:

Yes, yes. The wheel still works fine, right? Nevertheless it´s just a stone aged banal wheel. Even with Pirelli slicks.

Why not take some of those hollowed logs out to Le Mans and let us know how long they last? The advances were in materials, construction, bearings, etc., even though round things are still what roll.

I guess that we could put antigravity paint on the bottoms of our vehicles to be more modern, but wheels have a decided advantage in that they exist.

Link to comment
Share on other sites

Vivienne, all you do is troll and say the most negative things. Perhaps you are trying to show us all what fools we are by comparison to your obvious brilliance.

In this group you have to do better than that. Show us your mesh. Maybe then we will take you seriously. Otherwise, we will view you as what you are, an attention seeking troll.

Link to comment
Share on other sites


DanielRavenNest Noe wrote:

Luc, she does not have a good answer, because she is only here to troll and complain.

Yeah, I know. I just had to ask a few things to see if there was *anything* worthwhile in what she said. Clearly, there is not. So from now on, I'm going to ignore anything coming from her. It's obvious that reasoning and debating things with her is pointless, so I will suggest we all do our best to ignore her.

- Luc -

Link to comment
Share on other sites

Here are my 2 cents about Collada for everybody who does not exactly know what Collada is all about:

Collada is first of all a Format specification. it is not a software which needs update every 2 months to keep interesting. It is DESIGNED to be stable. Collada's aim is to provide an open protocol for 3D Model interchange between applications. The 3D Scene seems to be open minded about Collada and many (see link below !) 3D applications implement at least exporters for Collada-1.4.

I think there is NOTHING wrong about Collada beeing released in 2006. I think the opposite is true. If it does not need significant changes to keep up with the current development of 3D software, then it must be fit for its purpose ;-)

 

From all formats that could be choosen by LL, in my understanding Collada is the best choice they ever could do. Tell me any other format, which is open and as widely supported as Collada and allows the same level of complexity (static meshes, dynamic meshes (weighted mesh,rigging), even animation exchange seem to be supported by Collada...)

And this may be an interesting nesletter too (i was very astonished while reading it :smileywink: )

    http://www.khronos.org/newsletter/detail/official-collada-march-2011-newsletter

And finally one more thought: If Collada is stone aged, then what is XML and HTML ? 

Link to comment
Share on other sites


Gaia Clary wrote:

From all formats that could be choosen by LL, in my understanding Collada is the best choice they ever could do. Tell me any other format,
which is open
and as widely supported as Collada and allows the same level of complexity

 

Heh, without that distinction of "open" I could think of a couple formats.  In all honesty though the .blend file is an appropriate choice.  It has massive support (an entire open source community, plus a thriving business centered around maintaining Blender), is openly available, and supports quick loading at runtime (see Blender Games).  COLLADA is something exportable by most modeling programs though, while Blender's the only one that deigns to use the .blend format (lest the Autodesk master race dirty its genes with open source). 

 

Anyhow, to answer the initial questions is somewhat hard to explain unless you already know a thing or two about modeling, but...  Have you ever been working on a build or piecing together an avatar and thought one of these things to yourself:

 

  • "hmm...  that doesn't quite line up right."
  • "if only I could put a hole here and here on the same side of this cube I could make a door and window"
  • "Wow, I spent 20 prims making a shoe... why?"
  • "Why is my hair made of 200 prims?"

Mesh solves all of these issues.  It allows you to make one seamless object of a complexity that simple prims may never allow.  It also allows you to decide how your textures are applied.  If you want, you can make only a small portion of a larger texture fill a vast portion of your object in any shape you want (and if you look into UV unwrapping on Youtube, you'll see some pretty interesting shapes to be sure).  For some truly prodigious examples of meshes, look no further than your favourite 3D enhanced games (Assassin's Creed, Knights of the Old Republic, Crysis, Gears of War, etc.) or online sales sites like Turbo Squid.

 

Now, why do you need it?  You don't honestly.  If you're not a hard core builder, or even if you are but you can bend prims to your will and never see a limitation in them, it's not something you really have to get into.  Building will always evolve and change, but the use of prims will always be a solid and reliable way to prototype quickly.  But if you've ever wanted a useful skill to bring to the employment side of life ("Hey, I know how to model in 3D, check out these characters/buildings/objects of interest in my portfolio!"), or just want to improve your building quality "to the next level" then this is the way. 

There are a vast array of 3d modeling tools to choose from (Blender being one of the best free ones and featuring perhaps the most complete collection of tutorials freely available online) and (almost) all of them are as capable as the others when it comes to what can be done in SL at the moment.  There's also a thriving Blender community on SL, though the majority of them are currently focused on sculpties (a trend I see falling off fairly soon).  It should also be pointed out that making sculpties is actually a great deal harder than using the entirety of mesh making knowledge due to its strict limitations.  Just look up some tutorials on making trees in Blender and you'll have all you need to make a forest in half an hour.

Link to comment
Share on other sites

Thank you everyone for providing useful explanations and offered links. The information was very helpful. 

It sounds to me if mesh can do all this whizz bang stuff, there will be no need for prim builders/sculpty users like myself.  I have never created and sold what I do to make a profit...what little I sell doesn't even cover the costs of materials I spend with other merchants let alone even touch my tier cost.   I enjoy creating things from what many call primative tools....too bad the 3-d modelings programs don't offer a basic primative mode modeled on how it is done in SL....that I know how to do ...LOL.   Being able to create was a draw to come to SL and spend money.  Really, what is left to draw people into SL or retain them once teh shiny has worn off?

I understand the need for enhancements and improvements, but with every change it effects everyone to some degree.  I think many small mom and pop creators could vanish because the market place will become so complex we can't keep up.  Most of us do not  have the resources or skills to create mesh.  It sounds like the creativeness in SL may slide further  and will fall to a select few like it did in the past with the land barons (mesh barons?) This could be yet another blow to SL's ecomony.

*wonders how many more blows to the economy there will be before SL folds*. 

Link to comment
Share on other sites


Morgaine Christensen wrote:

 
too bad the 3-d modelings programs don't offer a basic primative mode modeled on how it is done in SL....that I know how to do ...LOL.   Being able to create was a draw to come to SL and spend money.  Really, what is left to draw people into SL or retain them once teh shiny has worn off?

You might want to know that Primstar-2 (for blender-2.5) will eventually contain a Prim-editor which is designed to work almost like the SL-editor does. It will make it possible to create mixed builds with Sculpties and regular prims using blender and uploading the builds to SL (creating Linksets right in your SL inventory).

Link to comment
Share on other sites

You are about to reply to a thread that has been inactive for 4118 days.

Please take a moment to consider if this thread is worth bumping.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...