<<VRML 2.0 - An Introductory view by examples
Presenting VRML
VRML is a file format for describing interactive 3D objects and worlds to
be used on the World Wide Web. Presently you can start
using VRML installing one of the following browsers :
- DimensionX's Liquid Reality (Linux, SGI Irix, SunSolaris,Windows95/NT) [LR]
- this browser presents almost all the VRML 2.0 functionalities (Sept 97), but does not work as a plug-in tool for Netscape
- Silicon Graphic's Cosmo Player (Windows95/NT) [Cosmo]
- this browser presents the majority of the VRML 2.0 functionalities and works as a plug-in for Netscape 3.x. Until Sept 97 the script node did not agree
with the VRML 2.0 standard
- Sony's Cyber (Windows95/NT) [Cyber]
- this browser presents almost all the VRML 2.0 functionalities (Sept 97), and it works as a plug-in tool for Netscape 3.x
- Real Space (Windows95/NT, Mac) [Real]
- VRwave (SGI, SunSolaris, Dec/Alpha, Linux) [VRwave]
Getting inside of VRML
The browser we used to test all the examples you will find in this text is the Liquid Reality for Sun Solaris [LR]. See [Instructions].
The VRML paradigm
The paradigm to produce VRML programs is based on nodes defining
a scene graph. Nodes are useful for doing 3D graphics, multimedia, and
interactive world building. Each node defines a name, a type and a
default value for its parameters.
There are two kinds of parameters: fields and events.
Fields can be called simply "fields" (private) or "exposedFields" (public);
Events can be sent from a Node to another
by an eventOut parameter and received by an eventIn. This can also be
done by exposedFields parameters (exposedField = eventIn + field + eventOut).
Events signalize changes caused by external stimuli and can be propagated
by the nodes using Routes, which connect an eventOut to an eventIn
of the same type. Events and Routes drive
the animation of the worlds.
Defining a VRML program
Your VRML program, named your-program.wrl, must have in its first line the characters :
#VRML V2.0 utf8
defining that it is a VRML file using UTF-8 encoding of the ISO 10646.
VRML files have the following contents (or part of) : [example-html] [run]
- #VRML V2.0 utf8
- # defining comments lines
- grouping and children nodes (e.g. Shape, Group, Transform, Script ...)
- prototype nodes (PROTO)
- routes (ROUTE)