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Mesh Vs. Sculpties

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Advanced - Mesh Vs. Sculpties
Doc Available online with images
https://sites.google.com/site/tradewindsyc/boat-building/mesh-vs-sculpties
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By 
Moo Spyker - (re-printed with permission)
      https://my.secondlife.com/moo.spyker
        Moo's SL store: http://maps.secondlife.com/secondlife/Aloha%20Spirit%20Bay/128/148/225
-- This is a document distributed from Tradewinds Yacht Club.
-- Do not repackage and re-distribute
-- Suggestions and submissions encouraged
-- As  a living document updates will be made at the URL and in-world at TYC in Dex

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                - A  Case of the 2 Chairs


"sculptie with extra bits"

"mesh is gonna be quite pointless"


I actually have heard people say these things about Mesh and had to make this note card because it pissed me off so much about the lack of knowledge on such an amazing thing here in Second Life. Mesh.

When Mesh is fully released it will make Sculpties 100% obsolete.

No matter what your opinion is. It is a fact that Mesh is better in every single way then Sculpties. Let me walk you through the details on exactly why that is. Here is a brief lesson about video game graphics in general. Everything you see in in Second Life is made up of "Polygons". Prims and Sculpties are all made up of them. Your computer graphics card is what is used to display all of these. The more polygons around you the more work your computer has to do to display them. So the lower the polygons the better and faster your computer can display them.

To See Polygons in-world

Ctrl + Shift + R

You may need to set Preferences
  • go to your Preferences in the Advanced tab
  • check "Show Advanced Menu" and "Show Developer Menu"
  • save and exit the window
  • then press Ctrl + Shift + R.
 It will go into wire frame mode, press it again to exit. You can see all the polygons behind the scenes.

A bit more in depth, a Prim, Sculptie and Mesh are made up of polygons. A polygon is made up of 2 or more triangles. A triangle is made up of 3 vertices (vertex). Vertex > Triangle > Polygon > (Prims, Sculpties, Mesh).

See L.O.D problems (Level of Detail) for more on Polygons

 
.

    So with Second Life a prim box should have 6 polygons because it has 6 sides however these have 54 polygons because they use 9 polygons per side to work with the prim system such as hollow, taper, cut, etc. With Sculpties every single Sculptie no matter how simple or complex, no matter how large or small, they all have 1024 polygons... This is because they use a 64x64 or proportional texture to use the colors of each pixel as a position for each vertex. So Sculpters, myself included, would simply "hide" unused vertices which works to create nice looking Sculpties but still puts more stress on the graphic card. So say you want to make a complex shape that looks like 2 boxes and save prims so you use Sculpties. Sure you saved on prims on the sim count, but your hurting everyone who views it with the high polygon counts where as with Mesh you could easily make the shape in 12 polygons vs 1024... Do you see already how inferior Sculpties is?

    The biggest thing Mesh is introducing is the ability to upload a "physical" model along with the visual model. Here is a example of a physical model (below); the blue box (lower left) is the physical model and the white ship (top) is the visual model. What we have in-world, is both together (lower right). A physical model is what your AV is actually walking on or bumping into, it is completely unseen. Physical models take up a huge amount of computer processing power. Most people have never noticed that every single Sculptie uses a sphere as its physical model no matter what the shape. So say you had a Sculpted square floor. Behind the scenes the physical model is round so you would fall through the corners of the floor so you basically have to use yet another invisible prim to make the floor solid (see Bounding Boxes). They do this to save on computer processing power and simplify the physical model. With Mesh you'll be able to custom fit your physical model to the Mesh which will save a hundred times more on computer processing because on a simple Mesh floor you can have the physical model 1 to 6 polygons instead of a sphere... Second Life also splits up the visual and physical aspects of the Mesh so physically moving vehicles such as cars, airplanes, spaceships can has a super low physical model but a extremely high visual model. Ive seen a 150,000 polygon ship take up only 13 prims physically and was able to be flown. That's equivalent to 150 Sculpties... that's INSANE!

    Another huge thing Mesh has over Scultpies is the ability to upload several LOD's (Level Of Detail) models. What these are is when you set your objects graphic setting to low, medium or high you can have a individual Mesh for each... So on low a wall in a house could be just 1 polygon. On medium it could have the baseboards and trim modeled in. On high you could go as far as to model in cracks or outlet plugs in the wall... This saves so much for people with lower end computers and you have complete control on how each setting looks. On the other hand with Sculpties SL simply reduces that 64x64 texture down so they have less resolution. Which on the lowest setting on most Scultpies I have are not even recognizable...

    Yet another thing Mesh has over Sculpties is how smooth they can look visually. The vertices in a Sculptie are all "snapped" to a 256x256x256 grid when they are uploaded here and do not have any decimal places. Its 256 because it uses the color of the pixels. The color range is 0 to 255. I make large ships and the exteriors are always very bumpy and rough looking because of that limitation. With Mesh I've already seen cars that are mirror smooth because Mesh uses a decimal point system when it places the vertices.

    Last major thing I can think of is Texturing. You will now be able to texture the correct way with Mesh. Since the max upload size currently in SL is 1024x1024 the highest resolution per polygon on a Sculptie is 32x32 pixels because you have no control over the "UV" mapping. UV mapping is basically how the texture is laid on top of the model. With Sculpties you are stuck with the default UV mapping and cannot edit it, instead you have to texture around that limitation which almost always creates a loss in resolution. With Mesh you will be able to apply a 1024x1024 to each polygon if you wish, meaning greater resolution. Here is a visual example 􀀆 as you can see it only takes 3 texture images all compressed into the same texture to make up the Mesh object. While the Sculpted texture needs a instance of every texture laid out again and again over 25 of the original 3 textures had to be duplicated out on the texture because of the lack of UV editing... Not to mention the polygon difference... The end result is visually the EXACT same.... so why use sculpties any more?

Here's a sum up of the FACTS about the pros and cons of each just off the top of my head.

Mesh Pro's:
- Most people who Sculpt already use programs that can do Mesh such as Blender and 3ds Max
- 1 to 64,000 Polygon counts per object = total control
- Ability to make custom physical models
- Physical and visual prim counts split up
- Low end computer friendly with Level Of Detail models
- Better and smoother looking
- Faster building times
- UV mapping

Mesh Con's:
- Higher upload $L costs

Sculptie Pro's:
- People are already used to it
- Low upload $L costs

Sculptie Con's:
- Every sculpt is 1024 polygons
- Sphere physical models
- Lost resolution on low graphic settings
- Slow building times (average sculptie for me takes at least 1-2 hours)
- No UV mapping
- Very graphics card intensive
- Creates tons of computer lag for low end users
- Bumpy on long smooth surfaces

About the Author Moo Spyker


    I've been using Sculpites ever since they first came out you can see my line of large ships I create have been with Sculpties since SL introduced it so I know a thing or two about them. I've learned all the tricks and techniques to creating with them. Ever since the beginning I have hated the Sculptie system. I've used 3ds Max in RL for 9+ years previous to SL and the way you have to work wit Sculpties is everything wrong about content design for video games. There is no optimization or concern about triangle or polygon counts what so ever. I had to adapt to it to be able to make decent looking stuff in here. With Mesh coming out I am very excited to actually be able to model the REAL way now!

Moo Spyker
  https://my.secondlife.com/moo.spyker
        Moo's store located: http://maps.secondlife.com/secondlife/Aloha%20Spirit%20Bay/128/148/225


(Editor's Note -- Please read the comments below -- good stuff there)

FROM Silk Aeon:
In this article I just read I should point out I never work with sculpts but there are some things Moo does not address. That fireplace can be made with the same polygons in sculpts, If the author (Moo) can't make, it is not sculpt problem. 64x64 is not a fixed size, the lowest size can go 8x4 for volume object. Also there is nothing said in article about the costs of a 1 prim mesh will always cost more than a 1 prim as sculpt. For example, that docks Moo uses with his ship are 2 prims, but they have a PE cost of 10 in my viewer (which I think are made with 2 meshes). I can do the same with 1 sculpt maximum -- my cost 2 prims. It is a matter of sculpt map size which determines how many polygons will be used, but unfortunately most sculpties just use the default 64x64 size for any simple shape -- even for shapes that only need 8x4 size but this is where lag comes from, not from sculpts, but from bad building techniques of sculpts. Sculpts still give best result in terms of parcel prim allowance 1-2 prims for most things. So the article is particularly true about mesh, and almost not very accurate about sculpts.


FROM [Anu]:  
Silk, I totally agree. Nice article about mesh but a bit unilaterally and not quite true regarding lag, bumpyness or building time of sculpties. It all depends on the creator's skills and application/program used if a sculptie causes lag, is bumpy or time consuming. With other words - also a mesh object can be bumpy, time consuming or is able to create 'tons of lag'...depending on the creator's skills and program used. Pros and Cons of Mesh vs Sculpties are equal. A pro for mesh is the ability to apply different textures, glow, shine on one mesh object. A def con is the always (!) higher PE of mesh.


A Case of the 2 Chairs

 

 





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