Glossary - An Introduction to Computer Graphics for Artists - page 307

Shaded Display A graphic representation of a three-dimensional object where
the object is drawn with fi lled colors based on the position and orientation of
a light source in combination with the shape and normals of the object repre-
sented on screen.
Shading Anomaly A condition where the shading on an object has no apparent
motivation.
Shape An object's combined attributes of boundary, surface orientation, and loca-
tion of all points relevant to description of its every surface deviation.
Shortest Edge-length Rule A method designed to help organize edge patterns by
fl ipping them so that all edges are as short as possible.
Simulation An interactive software product with the goal of accurately predicting
the outcome of user behavior in a given scenario.
Skeleton A topological representation of a skeletal system, where each joint
connection is a transformation matrix, for the purpose of animating an
attached model.
Smoothing A rendering effect dependent on averaged normals at shared edges
between faces. The result is a smooth gradient from light to dark across affected
edges, instead of a sharp line of contrast along the edge.
Snaps A tool that allows a user more exact control when positioning objects or ele-
ments in a scene. The tool allows a user to skip from one pre-defi ned unit to the
next, effectively eliminating slight errors due to uncertain mouse movement.

Soft Edge A designation for an edge that has averaged normals at every vertex.
Sphere A geometry primitive whose points are all equidistant from its center.
Created by revolving a semicircle around its full diameter.
Spherical Projection A UV projection along the normals of each face of a sphere.
Spline A type of curve built from weighted control points.
Spike An out of position vertex, usually with very long trailing edges.
Split Normal Two or more normals attached to a single vertex. The result of this
condition is a hard edge when rendered.
Spotlight A light containing a minimum of the following parameters: light loca-
tion, target location, penumbra.
Station Point A location from which another thing is measured.
Stretched Coordinates A condition where the shape formed by UVs does not
match exactly the shape of the vertices they are mapped to. The result is that any
texture map applied to an affected polyset will be distorted. Most often, this term
is applied to UVs that have either an identical U or V value. This happens when
UVs are projected from a parallel, instead of perpendicular axis.
Structure The manner by which a thing is built, or the representation of objects
that defi ne the shape of an object or collection of objects
Structural Detail Vertices or control vertices that defi ne a change in the shape of
the object they belong to.
Subject An object designated as a an absolute standard against which the likeness
of a CG model may be measured.
Subdivide To divide a face into smaller faces, either by dividing from existing
vertices or by adding new vertices at the center of all edges.