Expand Your Vocabulary
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avatar
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a physical manifestation of the user at the current viewpoint in a
world.
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backface culling
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specifies that polygons not facing the camera are not rendered (if you
can't see the polygons, don't waste time rendering them). This is
useful for solid objects.
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billboard
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an object that rotates around a specified axis so that it always faces
the viewer. Billboards are a useful optimization technique.
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browser
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a software program that can view VRML worlds. Also called a viewer
or a player.
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clipping plane
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clipping planes define the area in the
scene visible to the camera. The near clipping plane is the point
closest to the camera that is still visible; the far clipping plane is
the point farthest from the camera that is still visible.
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clone
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a copy, or instance, of an object. A clone defines the
selected object as a master for producing multiple instances. All
instances share this master description identically, tracking all
changes to its shape and appearance.
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crease angle
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the angle between the normals for two
adjacent faces of a polygon.
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dihedral angle
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the angle between two adjacent polygons.
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edge
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where two faces (polygons) of a model meet. The term edge is
different than the term line, in that it implies membership
in the face.
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event
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an indication that something has happened. Outgoing events send their
values to incoming events, which receive values. The connection between
two events is called a route.
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face
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a single polygon, defined by points and lines; may also refer to a
"perceived" face, which is a rendered "side" of an
object that may be composed of several polygons. A group of faces make
up a model's surface.
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iconic objects
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geometric placeholders for nodes which will be
invisible to a VRML browser, for example, sound and light nodes.
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IndexedFaceSet
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a VRML node that defines the coordinates
for a set of polygons that make a shape.
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inline
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a file referenced by URL (Uniform Resource Locator) within another
file. In VRML files, inlines are downloaded separately from the main
file and are a good way to speed up transmission and rendering of the
main file. Some browsers display inlines as bounding boxes while they
are loading.
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keyframe
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a pose at a particular time. The Keyframe Animator interpolates between
poses, filling in values to move from one pose to the next. A keyframe
can also contain values for viewpoints, textures, materials, and
shapes. The Keyframe Animator interpolates between the values to
transition from one viewpoint, texture, material, or shape to the next.
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line
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defined by two points (vertices) of a model; also see edge.
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LOD (Level of Detail)
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an object which appears to change to display the
appropriate level of detail depending on viewing distance. LODs are, in
fact, multiple representations of the same object.
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For example, if you are looking at a forest from far away, you don't
need to see the individual trees. The LOD might be made of large
polygons that represent a forest. As you get closer, the LOD is
replaced by another LOD made with more polygons so that you can see
tree trunks and leaves.
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mapping
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instruction for placement of packaged files.
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member
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an object within an animation that moves as a unit in the scene.
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normal vector (or normal)
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a directional line that is perpendicular to a
surface. A normal indicates the front of a face.
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object
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a single 3D item in a VRML scene, or an item that
is part of a grouped object's hierarchy.
orthographic projection
2D view of objects in a scene; typical
orthographic views are top, front, and side.
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package
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to locate all the files necessary to create a document or world and
organize them for publication on a Web server.
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PEP
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Points, Edges, Polygons. Refers to Cosmo Worlds's interface to the VRML
node IndexedFaceSet.
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PEP Editor
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the mode used to model PEP objects (PEP modeling). The PEP Editor is
indicated by an orange frame around the object you are editing.
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PEP object
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an object which has been converted to its individual points, edges, and
polygons.
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PEP modeling
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editing an object's points, edges, and polygons; edits the coordinates
inside the IndexedFaceSet node.
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perspective projection
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3D view of objects in a scene.
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point
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a single vertex in a model.
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polygon
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in Cosmo Worlds, a face of a model, defined by the model's points and
edges.
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proxy
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an object to be used for collision detection in place of actual
geometry, which is usually more complex than the proxy.
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publish
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to copy a set of packaged files to a Web server where they can be
accessed by Web clients.
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root
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a top-level document or world in the packaging directory. All files
referenced in this document, as well as the local files referenced by
those files, will be included as part of the package.
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route
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connection between two events.
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surface
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a set of faces; the surface of a cube includes all of its faces.
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VAG (VRML Architecture Group)
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a group of technical experts formed to set standards
for creating and displaying 3D worlds on the Web. See the VAG home page for additional
information.
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VRBS (Virtual Reality Behavior System)
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a VRML behavior scripting system prototype developed
by the San Diego Supercomputer Center (SDSC). See the VRML
Behaviors home page at the SDSC for more information.
VRML (Virtual Reality Modeling Language)
VRML is a standard way to specify 3D objects for viewing
across the World Wide Web.
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VrmlScript
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a programming language, similar to JavaScript, that is used for scripts
contained in a Script node. Click
here for the complete VrmlScript specification.