What is VRML and how does it differ from HTML ?

VRML (Virtual Reality Modeling Language) — VRML (pronounced as “V-R-M-L” or “ver-mal”) is a modeling language which helps to create platform-independent 3D objects and interactive scenes on a web page. It was first introduced in 1994 at the first World Wide Web conference by Mark Pesce, Tony Parisi, and others. VRML had initially stood for Virtual Reality Markup Language. The VRML files are known as worlds and have “.wrl” extension. A VRML world is built using nodes. Nodes describe the geometry, sound, properties of the world, and more.  

Three versions of VRML are VRML or VRML 1, VRML 2.0, and VRML 97. At the time when VRML was introduced, most of the businesses as well as other users were accessing internet through slow dial-up connections. The lack of bandwidth proved to be a major hindrance in increasing the popularity of VRML. VRML was used as a data-exchange format for 3D models, particularly in CAD (Computer Aided Drafting) programs. In 2001, X3D was introduced as an XML encoding of VRML.

VRML and HTML are similar in many ways. Both are written as text files, are platform independent and both HTML documents as well as VRML worlds can contain links to other worlds, documents or resources located anywhere on the Web. However, they differ in the fact that HTML documents are 2D whereas VRML worlds are 3D. VRML was also referred to as the 3D equivalent of HTML. Unlike other programming languages like C and C++, VRML is not compiled and then run, instead VRML files are parsed and displayed.

HTML: HTML stands for Hyper Text Markup Language. It is used to design web pages using markup language. HTML is the combination of Hypertext and Markup language. Hypertext defines the link between the web pages. Markup language is used to define the text document within tag which defines the structure of web pages. This language is used to annotate (make notes for the computer) text so that a machine can understand it and manipulate text accordingly. Most markup languages (e.g. HTML) are human-readable. Language uses tags to define what manipulation has to be done on the text.

HTML	VRML
It is a markup language.	It is a modeling language.
It creates 2D documents.	It creates 3D worlds.
HTML is not case-sensitive.	VRML is case-sensitive.
All HTML versions are backward compatible.	No backward compatibility among VRML versions.
It uses markup tags.	It does not use markup tags.
Files have .htm or .html extensions.	Files have .wrl extension.