Subdivison primer/glossary
Wikipedia，自由的百科全书
This glossary is not an exhaustive list of tools and features. It is intended to support the Primer in helping people who are new to 3D modelling get a feel for what everything means.
BANDSAW
This is Lightwaves implementation of Split face loop and allows the modeller to very accurately split a selected line of faces thus adding a new loop of Edges.
BACK FACE CULLING
This is where the back of a Polygon Face is made transparent
EDGE
Or Polygon Edge is the term used to define one side of a polygon face that has a point at each end
EDGELOOP
A series of edges connected by four edged vertices, at each vertice the loop continues along the edge which does not border a polygon shared by the previous edge. Contrary to popular belief it does not have to be a closed loop.
EXTRUDE FACE/EDGE
A very useful tool that is usually performed on a selected Face or Edge. It literally extrudes a new polygon out from the parent and creates new Face and Surrounding geometry as a result.
EXTENDER
Lightwaves implementation of Extrude Edge
GEOMETRY
What is geometry?
GRID
A virtual plain in 3D space that usually take the form of a grid pattern.
INTRUDE
a command usually found in solid modelers which hollows out the model (not to be confused with extrude!)
KNIFE
A Lightwave tool that slices through geometry with a straight line
LATHE
A command which creates a 3 dimensional polygon object by rotating a spline or line.
LATTICE
A lattice is a cage of sorts that has an influence over the shape of the geometry it contains.
LOFT
A command which creates a 3d polygon object by connecting a series of splines or lines with a "skin" of polygons.
FACE
Or Polygon Face. A componant of a polygonal model that is comprised of three or more Points and Edges.
MANIPULATOR
A manipulator usually sits at the central pivot point of an object and has controls for moving, rotating and scaling the object in 3D Space. It usually has a different color for each axis
MODELING HISTORY
Typically maintains a serial progression of modeling steps wherein the earlier steps influence the later ones. This differs from parametric modeling where features can affect ones that weren't necessarily modeled after it.
N-GONS
A polygon with more than 4 sides. Not all modeling programs support N-Gons and to make a model as compatable as possible it is best to limit the amount of N-Gons used in a model.
==NORMALS ==(Also known as Surface Normals)
NURBS
(not covered in this article)NURBS, short for non uniform rational B-spline, is a computer graphics technique for drawing curves. A NURBS curve is defined by a set of weighted control points, the curve's order and a knot vector.
PARAMETRIC MODELING
Wherein the software maintains the relational attributes of a feature. Parametric modeling allows one to develop relations between features and hence can be contiuously updated
PATCH
A surface generated by 4 intersecting splines where the surface is generated within the intersecting boundary
PIVOT POINT
A point on or in an object that acts as a pivotal centre. If the object is rotated it revolves around the pivot point.
POINT
See Vertices. A point is one component part of a polygon face. Points are connected by Polygon Edges.
POLE
a vertex (point) that connects 3, 5 or more edges also sometimes called a star.
POLYGON
A geometric shape generally made up of Points, Polygon Edges and a Polygon Face. Several Polygons joined together form an Object.
POLYGON LOOP
A series of polygons bordered by two edge loops.
RAIL SWEEP
Similar to sweep but uses a profile spline, a path spline and one or more rail splines which describe the scale of the profile at any given point. It can be used to create objects of variable cross section like a trumpet.
SMOOTH SHIFT
This is Lightwave's version of an Extrude Command and works by Extruding a selected polygon or Edge out from an existing component part.
SOLID MODELER
Most polygon modeling applications treat the model like an egg shell which means you can have a single polygon in isolation or a plane created from a single layer of polygons, these are 2 dimensional models. A few applications, notably Mirai, Nendo and Wings3d are solid modelers. That is they treat the model like a piece of clay which always has 3 dimensions.
SPLINE
A 3 dimensional line used to describe paths and profiles in polygon modeling. Bezier splines are probably the most powerful and are almost identical to the Bezier paths found in many 2d applications like Photoshop.
SPLIT POLYGON
A command that allows a modeler to add new edges by splitting polygons. Usually by clicking on a point or edge then moving to another point or edge and clicking again.
SPLIT FACE LOOP
A command that splits a line of selected faces in two (Also see Bandsaw)
STACK
See modeling history
STAR
see pole!
SUB-DIVISION SURFACES
These are polygons models than have a control cage that has a subdivided, derived surface. Sub-Division modeling allows you to create a polygonal model that acts as a `controller` that contains the structure of the smoother, subdivided one. Only the smoothed version is taken into account at render time. It is achieved by using sub-division algorithms (math routines that do the smoothing)
SURFACE NORMALS
(See NORMALS)SWEEP
A command which creates a 3d polygon object by tracing the movement of a profile spline along a path spline. This can be used to create objects of constant diameter like a pipe.
TRI
Or Triangle is a Polygon face with three points and three Edges.
VERTEX, VERTICES
A point in 3D Space that, along with Edges defines the perimeter of a Polygon face.
WIDGET
Another name for manipulator.
WIREFRAME
This is how geometry is viewed when the Polygon faces are hidden and literally looks like a model made of wire.
WIREFRAME SHADE
This mode of viewing a model is a popular way to view the model during its creation. It allows the modeller to see the polygon faces but also the Wireframe over the top. It is popular because it allows you to see and select all of the component parts of a polygon (e.g.. Points, Edges, Faces or the entire object)
XYZ
Common/Generic names for the Axis in 3D Space. X for left and right, Y for up and down and Z for in and out.
ZSPHERE
A modelling tool in ZBrush that uses ZSpheres and Link ZSpheres to define a shape that can be converted to geometry
ZBRUSH
An innovative 3D program from Pixologic that combines 2D and 3D tools. Although the current version (V.2.0) doesn't contain many traditional polygon tools it makes up for this with a range of Sculpting tools and brushes.
Xdugef
A fictional modeling technique often mentioned by experienced modelers in order to confuse beginners!
