Glossary - An Introduction to Computer Graphics for Artists - page 298

Assembly View A technical drawing of all parts of a given object, as they appear
when joined together in their proper positions.
Attached Combined for the purpose of translation, but without losing individual
identity
Attribute A characteristic of any element in CG, usually governed by user-defi ned
variables.
Averaged Normal The average of two or more normal values. Used to cause
smooth shading at any given vertex or number of vertices.
Axis The line about which a rotating body turns.
Back-Facing Polygons Polygons whose normals point away from the desired
direction, usually by 180°.
Bevel To cut at an inclination that forms an angle other than a right angle.
Boolean OperationWhen two or more objects intersect, the intersection boundary
is calculated for the purpose of modifying one or more of the intersecting objects.
In a Union operation, all polygons from all polygons that penetrate each other are
subtracted, and the remaining polygons combined into a single polyset. In a
Subtraction operation, the shape of one or more polysets is subtracted from the
other. In an Intersect operation, all faces that do not exist within penetration
boundaries are removed and the remainder made into a single polyset.
Boundary A line defi ning the limits of an area.
Bow-tie Face An n-sided face (usually a quad) that has been twisted so that its
normals, if triangulated, would be facing almost 180° away from each other.
CAD An acronym for Computer-aided Design .
CAM An acronym for Computer-aided Machining .
Card Geometry Usually one or two triangle planar polysets, combined with an
opacity map to change the silhouette of the polyset. These are most often used to
represent plants and trees.
Cascading Effect A series of actions that occurs in successive stages, each of
which is dependent on the preceding one.
Center A point that is equidistant from the furthest bounding points of an object or
collection of objects.
Checklist A list of items to be checked for compliance with project criteria or
industry standards.
Child Node A dependent node .
Circle A planar curve where every point on its surface is equidistant from its center
point.
Circumference The length of a circle.
Clean Geometry The contents of a 3D fi le when those contents are free of techni-
cal errors, well organized, and a good likeness of the subject.
Closed To join the endpoints of, and cause them to be inseparable.
Coincident Two or more vertices, edges, faces, or polysets that share exactly the
same vertex coordinates.
Compatibility Capable of being used by more than one application without change.
Component A subordinate part of a geometric entity.
Component Editing The editing of a component .