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Tip of the Day
Language: DHTML
Expertise: Beginner
Mar 25, 1997

Why won't my VRML browser work with 2.0?

Question:
I went to see one of the new VRML 2.0 sites, but only saw blackness. What is going on? Why won't my VRML browser work with the new version?

Answer:
Just when you'd become accustomed to writing VRML 1.0, had set up your favorite browser and list of sites, knew which world builder to use and something about how to optimize code produced by it, along comes VRML 2.0. The VRML community is heard cheering in the background, but where does that leave the end user who just wanted to have some cool 3D on her site, or the commercial site manager who doesn't know what changing to VRML 2.0 is going to mean for him?

All you may have noticed so far is that when you reach some sites, and your VRML browser kicks in, all you see is blackness. That's because all VRML files, be they 1.0 or 2.0, have the suffix .WRL, and this is what triggers the browser to start up. But once the VRML 1.0 browser starts to parse the file, it hits the new header line: #VRML V2.0 utf8 and can't proceed.

Originally, VRML was ASCII text-based -- restricted to 127 symbols and control characters. This was fine for English speakers, but not too useful for Japanese and Chinese people using thousands of different characters encoded as multi-byte or Unicode values. So VRML 2.0 has shifted over to UTF-8, and the old ASCII-text node has been replaced by a new Text node, which can handle Unicode details like text direction and specifying which language is being used.

All of this is very useful but, if you go cruising the Web with your fine new VRML 2.0 browser and visit your old favorite world written in VRML 1.0, you hit the same blackness because this time there's the old header line: #VRML V1.0 ascii and the new browser can't parse it. This is actually sensible because there's more to the new format than just a change of header and some new nodes; some important structural changes have been made. But until dual-mode browsers appear, or until everyone changes over all VRML code on their sites to the new format, there are going to be continuing glitches as incompatible browsers stumble over sites from the wrong side of the VRML gulf.

This is the reason there has been so much resistance to the idea of a VRML 3.0 -- each change of format renders all previous files obsolete unless browsers maintain backwards compatibility.

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