VRML

Assignment 2:VRMLThis section answers many of the common questions about VRML, including: ∙What is VRML ?o Should I learn the VRML format ?∙VRML Web Pageso How do VRML Web Pages work ?o How can I make VRML Web Pages ?o What can I use VRML Web Pages for ?∙The Future for VRML1.What is VRML?VRML which stands for the Virtual Reality ModellingLanguage, is the international standard for "Virtual Reality" - 3D content on the internet/web. The VRML standard was first adopted back in October 1994 and has since undergone several version updates (VRML 1.0, VRML 2.0, VRML97 and most recently the X3D Draft Specification) to enable more complex and interactive content to be displayed. For a more thorough description of the VRML standard (tech docs) take a look at the VRML International Standard.In essence VRML is the format or language that is used/required for 3D interactive worlds. It specifies how such worlds should be described so as to work smoothly on the web as interactive 3D content.The VRML format can be used in either human readable text format form or in a compressed (non human readable) format. As the compressed format (often seen as worldname.wrl.gz) makes for smaller file sizes and hence faster downloads, it is more commonly seen on the WWW.1.1Should I learn the VRML format ?That depends, VRML is currently much like HTML was in the early days of the web. Back then it was not uncommon to see pages being written by hand in HTML. However as we have seen with HTML, over time tools have been developed to enable development of web pages using interactive graphical tools that don't require the developer to have any knowledge of the underlying HTML format.At the moment most of the interactive VRML pages that we see on the web are hand written. However easy to use interactive tools are now beginning to appear for VRML development (eg. VRMLmagic). It is likely that (as was the case with HTML) as time goes by, the need for a detailed knowledge of the specifics of the VRML standard itself will become less relevant (and experience with the higher level world building tools will become a more useful skill).2.VRML Web PagesA VRML web page is the textual description (sometimes compressed for efficiency) of a 3D world and the items that make it up. This description includes items like backgrounds, objects (ie. geometric structures), lights and cameras (ie. fixed viewpoints). This world is described textually using the rules of the VRML format. Such VRML worlds can also include interactive content (eg. objects can interact with users and move, fade, make sounds etc). When you view a VRML world in a webbrowser what you see is the browsers representation of the world as described in the VRML file.It is usually the case that a VRML web page (or world) is made up of a series of files. The main file being the descriptive world file (ie. the worldname.wrl or worldname.wrl.gz file) and other files such as images (used for texture mapping onto objects) or sound files (used for playback in the browser).2.1How do VRML Web Pages work?Having developed your VRML world (either by hand writing it or using a tool like VRMLmagic), it functions as interactive 3D content on the web based on the following system:∙From within a browser application, the user clicks a VRML world file (eg.worldname.wrl)∙Browser identifies filetype of the main world file (eg worldname.wrl) as a VRML world∙Browser recognizes that it cannot directly display VRML worlds so it seeks a plug-in application to display the VRML content∙If user has a VRML plug-in then that plug-in application takes control of the window area specified and begins to load the VRML world∙The VRML file (containing the description of the world) is parsed (read through) by the plug-in and the geometry/lighting etc as described in the file is constructed and a 3D view of that world is displayed in the window areacontrolled by the VRML plug-in.∙The user can then view and interact with items in the 3D world (as it is displayed by the plug-in application)There are several options for building VRML worlds. In simple terms they break down into two areas:∙Use a Development Tool (eg. VRMLmagic) - on the positive side these are easy to use, give you easy access to the most powerful features of VRML andallow you to begin developing immediately without needing to learn thecomplex details of the VRML format.∙Hand Write a VRML File - this is clearly the best way to learn VRML development, however it will take you a lot longer, but if your objective is tolearn the details of the format then hand writing may be for you. Keep in mind that VRML is a relatively complex format and to access many of the powerful features (eg. animation and interaction) you will also need to have experiencewith programming and/or scripting.If you're planning on hand-writing your VRML worlds, we highly recommend that you get a hold of some of the reference books on writing VRML, in fact these books are recommended reading for anyone who wants to delve into the workings of VRML.As a general rule its probably best to use Development tools where possible as they generate reliable VRML and enable you to access many features that are difficult to implement by hand. If you're looking for the best of the development tools, they fall into one of three categories:∙Enhanced Text Editors - As VRML is a text based format, most of the current VRML authoring tools are basically enhanced Text editors, allowingyou to write your world by using some "enhanced" text editing features thatenable you to textually add differing node types from within the text editingsystem. These aren't hugely different to hand writing your world but they dooffer some features that make it quicker and easier to do the actual writing.∙Static Object Modelling Tools - Many/Most of the object modelling and CAD tools now support the VRML file format as an output option. These tools are excellent for constructing the geometric shape of complex objects,however they do not target VRML and as a result they are really only usefulfor making static objects (ie. they can't access the interactivity, multi views etc that VRML can make use of).∙Interactive VRML Specific Development Tools - These tools are aimed at making interactive VRML content and as such are the most likely to be of use (eg. VRMLmagic provides an interactive 3D workspace for you to lay outyour world and then you can simply add interactions by choosing from sets of available pre-defined actions. When compared to the complex VRML work,not to mention the scripting, needed to do this by hand, these tools willcertainly make building interactive 3D VRML files easier and much faster.VRML enables you to create interactive 3D content, for example you could make something as simple as a 3D heading or you could create large complex virtual reality style environments. The VRML format itself has no limitations on size or type of 3D content, so you can use it to make whatever type of 3D content you choose. Of course if you are planning to build large/complex VRML environments or worlds, its probably worth looking into the available VRML development tools to help with this (as its a huge task to hand write large complex worlds).VRML can be used for a range of possibilities, ranging from its original objective (ie. virtual reality on the web), where you specify a "world" in VRML and the user is able to walk around inside that virtual world. But its also very suited to smaller 3D elements (eg. 3D heading that spins or interactive 3D navigation bars) for web pages.Although you can simply use VRML to create and view your own 3D worlds locally (on your personal machine), the big advantage of VRML is that it is the internationally adopted standard for 3D content on the web and as such you can publish your VRML worlds for viewing on the internet.3.The Future for VRMLWith the development of X3D (the new version of VRML) currently underway, we are just now beginning to see the next step in the evolution of 3D web content. The title VRML may fade away but interactive 3D web content is now, for the first time, poised to become more than just a niche part of the web. Many of the issues that have held 3D back in the past are now either solved or being resolved and the future looks bright for VRML (in the form of its newest version X3D). We know that there is demand out there for 3D content and with the increasing availability of high end 3D graphics hardware, the issues of 3D performance are becoming less relevant. With todays mainstream machines now more than capable of displaying the richestX3D/VRML worlds.We are also beginning to see X3D/VRML development tools becoming available. Bringing VRML/X3D development to the masses. History has shown us the enormous growth that good development tools can make, bringing a whole new set of developers into the market.。