Sculpted Prims: 3d Modeling Glossary

(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.

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 color 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 efficiency (i.e., reduces lag). Why bother to compute all the details of objects that are far away?

NURBS Modeling

NURBS is short for “Non Uniform Rational Bézier Spline”. This modeling 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 modeling 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

A methood of modeling that takes some of the best features of both NURBS and polygon meshes in which you manipulate a series of controll points on a model. The number of controll points can be increased (subdivided) or decreased at will, offering great flexability between fine and coarse controll.

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 colors 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 “color 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 or vertexes.

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

See also

• Sculpted Prims: FAQ
• Sculpted Prims: 3D Software Guide
• Sculpted Prims: Technical Explaination
• Sculpted Prims Talk Page