Difference between revisions of "Sculpted Prims: 3d Modeling Glossary"

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=Advanced Modeling Glossary (as is applies to Sculpties in Second Life)=
<span id="SculptedPrims">
;Sculpted prims </span>
:A new prim type in Second Life. A sculpted prim is a prim whose shape is determined by a texture &mdash; its “sculpt texture”. Sculpted prims will allow for custom and more complex shapes to be brought into SL and used in building.
 
 
<span id="SculptMap">
;Sculpt Texture or “Sculpt Map”</span>
:Sculpt Textures are image files that contain the data for the shape of a sculpted prim. A sculpt texture is a standard RGB [[Textures|texture]] where the R, G and B channels are mapped onto X, Y, and Z space. A sculpt texture is very similar to a “[http://en.wikipedia.org/wiki/Normal_mapping normal map]”, but instead of encoding surface normals it encodes surface positions. See [[Sculpted_Prim_Explanation|this wiki page]] for a detailed explanation.
 
 
<span id="StitchingType">
;Stitching type</span>
:Remember, a sculptie map is really a flat (i.e. 2 dimensional) square which is applied to and deforms a Second Life prim.  As a square, it has edges.  If you want to shape it into something that doesn't have edges (i.e. is 3 dimensional), you need to "stitch" those edges together.
:*'''Sphere:''' when you select spherical stitching, the left and right sides of the square are stitched to each other, and the top and bottom edges are stitched to a single point.
:*'''Cylinder:''' when you select cylindrical stitching, the left and right sides of the square are stitched to each other, but the top and bottom are left unstitched.
:*'''Torus:''' when you select torus stitching, the left and right sides of the square are stitched to each other, and the top and bottom are also stitched to each other.
:*'''Planar:''' when you select planar stitching, all the sides are left unstitched.  (This is the same as selecting "none".)
 
 
<span id="AmbientOcclusion">
;Ambient Occlusion </span>
:A methood of calculating light and shadow on a 3d model with simulated ambient (non-directional) light.  Some programs refer to this as "sky light".  This is a fairly easy way to bake pre-rendered shadows onto a model.
 
 
<span id="Edge">
;Edge </span>
:An edge is any line drawn between two verticies and are one of the three sub-components of a polygon model that can be manipulated.
 
<span id="Face">
;Face </span>
:Faces, also called polygons, are one of the three editable sub-components of a polygon model.
 
<span id="LOD">
;Level of Detail (LOD)</span>
: Objects in 3D graphics are usually represented by a web or mesh of polygons, each with various properties such as colour and texture.  When the camera is very close to an object, you need a lot of polygons to represent the detail.  When the camera is far away, you only need a few larger polygons.  This improves SL efficiency (i.e., reduces lag).  Why bother to compute all the details of objects when they are too far away to be visible anyway? 
 
 
<span id="NURBS">
;NURBS Modelling</span>
:NURBS is short for “[http://en.wikipedia.org/wiki/NURBS Non Uniform Rational Bézier Spline]”. This modelling method uses a series of curves and control points to define the model’s shape. If you have already worked with the Pen tool in Photoshop, Illustrator and similar programs, you’ve worked with Bezier curves in 2D. NURBS take the same concept into 3D. According to Qarl Linden, NURBS are the best thing to use for sculpt prims; it makes some sense since he worked most recently in movie special effects where NURBS are commonly used.
 
 
<span id="PolygonMesh">
;Polygon Mesh</span>
:The [http://en.wikipedia.org/wiki/Polygon_mesh Polygon Mesh]is the most common modelling method used in 3D computer graphics (including Second Life). The process involves the direct manipulation of polygons (triangles and quadrilaterals), faces, vertices and edges to produce the desired shape.
 
<span id="SubdivisionSurface">
;Subdivision Surface </span>
: Also known as 'subsurf': a method of modelling which takes some of the best features of both NURBS and polygon meshes in which you manipulate a series of control points on a model.  The number of control points can be increased (subdivided) or decreased at will, offering great flexibility between fine and coarse control.


Sculpted prims: Second Life’s upcoming new prim type, which will allow for custom and more complex shapes to be brought into SL and used in building.
<span id="TextureMaps">
;Texture Maps</span>
:In SL, [[Textures|textures]] are usually used to store pictures of something.
A ''Texture Map'' is 3D graphics lingo for an image that uses the colours to represent some data.  In the case of sculpties, it is the <x,y,z> coordinate of the surface of the object.
The textures most SLers know and love are also known as “diffuse maps” or “colour maps” within most programs; some people may also be familiar with “opacity maps”, “bump maps” and “[http://en.wikipedia.org/wiki/Normal_mapping normal maps]”.


Sculpt Texture: (or “sculpt map”) the image file that contains the data for the shape of the sculpted prim.  Basically, each vertex’s x,y,z value is encoded as a RGB color value similar to the way “normal maps” in many new computer and video games do. At this writing, this process is done by a plug-in in the Maya modeling program (the code for which is freely available), it looks like SL community members have already figured out the process in Blender and should release a script before too long.  Support for other programs should come quickly and an in-world tool is planned “eventually”.
<span id="Unwrap">
;Unwrap </span>
:Unwrapping is the process of manually taking a 3d model, defining its seams, and creating a flat template that defines how textures appear on that object.  Clothing and skin designers are familiar with the SL avatar templates provided by Linden Lab and other residents; those are the end-result of an unwrapping process.


- What is the recommended size for sculpt textures?
<span id="UVWMap">
64 by 64 pixels.  Anything larger will be scaled down when you upload.  This is also the default export size.
;UVW Mapping </span>
- Can sculpt textures be created in Photoshop or other paint programs?
:The data in a model that defines the positioning of its textures, either automatically, via an unwrapping process or using a preset projection such as planar mapping, face mapping, box mapping, spherical mapping, etc.
Not easily.  However, given a pre-made sculpt texture and an understanding of how they work, you can use a paint program to manipulate them and achieve certain effects.  Check the related discussion page on the SL wiki for more details.


Maps: 3D graphics lingo for “texture map”, or what most SL residents know as textures. The textures most SLers know and love are also known as “diffuse maps” or “color maps” within most programs; some people may also be familiar with “opacity maps”, “bump maps” and “normal maps”You will also come across the term “UVW Map”, which is basically the data that defines how a texture appears on a model.
<span id="Vertex">
;Vertex </span>
:In a polygon mesh a vertex is a single point in 3d space and the smallest editable component of a model. The plural is ''vertices'' (the correct Latin plural) or ''vertexes'' (a less-used alternative with an Anglicised ending).
Two verticies joined create an ''edge'', three or more create a ''face''Faces are sometimes called ''polygons'' or ''polys''.


Polygon Modeling: The most common type of 3d modeling method used in games (including Second Life).  The process involves the direct manipulation of polygons (triangles and quads), faces, vertices and edges to produce the desired shape.
== See also ==


-Can polygon models be exported as sculpt textures?
:* [[Sculpted Prims: FAQ]]
Yes, with care and with some restrictions.  See the SL Wiki for details.
:* [[Sculpted_Prims:_3d_Software_Guide|Sculpted Prims: 3D Software Guide]]
-What’s the maximum polygon count I can have?
:* [[Sculpted Prims: Technical Explaination]]
It’s easier in this case to count vertices instead of polygons.  Up to 1024 vertices will be rendered by the client for any given object, so you should keep your model under that count.  If you need more, split your model up into multiple prims.  For reference, a torus in SL has about 1000 verticies.
:* [[Talk:Sculpted_Prims|Sculpted Prims Talk Page]]


NURBS Modeling: NURBS is short for “Non Uniform Rational Bézier Spline”; it’s a method of modeling that uses a series of curves and control points to define the model’s shape.  If you have already worked with the Pen tool in Photoshop, Illustrator and similar programs, you’ve worked with Bezier curves in 2D; NURBS takes the same concept into 3D.  According to Qarl Linden, NURBS are the best thing to use for sculpt prims; it makes some sense since he worked most recently in movie special effects where NURBS are commonly used.


-Can my 3D program do NURBS models?
[[Category:Sculpted Prims]]
NURBS used to be the feature that separated professional-quality programs from the rest, although that gap is narrowing to a degree.  In general, Max, Maya and Blender all do both NURBS and polygons.  Many common “free and easy” or low cost programs like Google Sketchup, Milkshape, Wings3D and gMax do not.  Rhino3d is a commercial program (though considerably cheaper than Max or Maya) that specializes in NURBS modeling.  Other programs, including free ones, are currently being discussed on the Wiki.  The topic of “what program should I use?” is really a whole document in itself.

Latest revision as of 22:40, 24 January 2009

(This is work in progress)

Sculpted prims
A new prim type in Second Life. A sculpted prim is a prim whose shape is determined by a texture — its “sculpt texture”. Sculpted prims will allow for custom and more complex shapes to be brought into SL and used in building.


Sculpt Texture or “Sculpt Map”
Sculpt Textures are image files that contain the data for the shape of a sculpted prim. A sculpt texture is a standard RGB texture where the R, G and B channels are mapped onto X, Y, and Z space. A sculpt texture is very similar to a “normal map”, but instead of encoding surface normals it encodes surface positions. See this wiki page for a detailed explanation.


Stitching type
Remember, a sculptie map is really a flat (i.e. 2 dimensional) square which is applied to and deforms a Second Life prim. As a square, it has edges. If you want to shape it into something that doesn't have edges (i.e. is 3 dimensional), you need to "stitch" those edges together.
  • Sphere: when you select spherical stitching, the left and right sides of the square are stitched to each other, and the top and bottom edges are stitched to a single point.
  • Cylinder: when you select cylindrical stitching, the left and right sides of the square are stitched to each other, but the top and bottom are left unstitched.
  • Torus: when you select torus stitching, the left and right sides of the square are stitched to each other, and the top and bottom are also stitched to each other.
  • Planar: when you select planar stitching, all the sides are left unstitched. (This is the same as selecting "none".)


Ambient Occlusion
A methood of calculating light and shadow on a 3d model with simulated ambient (non-directional) light. Some programs refer to this as "sky light". This is a fairly easy way to bake pre-rendered shadows onto a model.


Edge
An edge is any line drawn between two verticies and are one of the three sub-components of a polygon model that can be manipulated.

Face
Faces, also called polygons, are one of the three editable sub-components of a polygon model.

Level of Detail (LOD)
Objects in 3D graphics are usually represented by a web or mesh of polygons, each with various properties such as colour and texture. When the camera is very close to an object, you need a lot of polygons to represent the detail. When the camera is far away, you only need a few larger polygons. This improves SL efficiency (i.e., reduces lag). Why bother to compute all the details of objects when they are too far away to be visible anyway?


NURBS Modelling
NURBS is short for “Non Uniform Rational Bézier Spline”. This modelling method uses a series of curves and control points to define the model’s shape. If you have already worked with the Pen tool in Photoshop, Illustrator and similar programs, you’ve worked with Bezier curves in 2D. NURBS take the same concept into 3D. According to Qarl Linden, NURBS are the best thing to use for sculpt prims; it makes some sense since he worked most recently in movie special effects where NURBS are commonly used.


Polygon Mesh
The Polygon Meshis the most common modelling method used in 3D computer graphics (including Second Life). The process involves the direct manipulation of polygons (triangles and quadrilaterals), faces, vertices and edges to produce the desired shape.

Subdivision Surface
Also known as 'subsurf': a method of modelling which takes some of the best features of both NURBS and polygon meshes in which you manipulate a series of control points on a model. The number of control points can be increased (subdivided) or decreased at will, offering great flexibility between fine and coarse control.

Texture Maps
In SL, textures are usually used to store pictures of something.

A Texture Map is 3D graphics lingo for an image that uses the colours to represent some data. In the case of sculpties, it is the <x,y,z> coordinate of the surface of the object. The textures most SLers know and love are also known as “diffuse maps” or “colour maps” within most programs; some people may also be familiar with “opacity maps”, “bump maps” and “normal maps”.

Unwrap
Unwrapping is the process of manually taking a 3d model, defining its seams, and creating a flat template that defines how textures appear on that object. Clothing and skin designers are familiar with the SL avatar templates provided by Linden Lab and other residents; those are the end-result of an unwrapping process.

UVW Mapping
The data in a model that defines the positioning of its textures, either automatically, via an unwrapping process or using a preset projection such as planar mapping, face mapping, box mapping, spherical mapping, etc.

Vertex
In a polygon mesh a vertex is a single point in 3d space and the smallest editable component of a model. The plural is vertices (the correct Latin plural) or vertexes (a less-used alternative with an Anglicised ending).

Two verticies joined create an edge, three or more create a face. Faces are sometimes called polygons or polys.

See also