D20 System Guide, Meaning , Facts, Information and Description
- '' d20 is also a kind of polyhedral dice.
The d20 is an open system. Other designers may use it free of charge, that is, without paying for a license (subject to certain restrictions). The d20 System is credited with developing the idea of open gaming.
Mechanically speaking, the d20 system is similar to older proprietary game systems such as the d10-based Interlock system used by semi-defunct publisher R. Talsorian Games. The basic mechanics involve adding a skill modifier to an ability modifier and rolling a die to compare to a target number.
The d20 System isn't the first system attempting to be universal, but it is the most popular. GURPS from Steve Jackson Games had been the most popular universal role-playing system since its creation in 1986.
Before universal systems, there were as many proprietary game systems as game designers. The licensing scheme for the d20 System is known as the Open Gaming License or OGL. Followers of the Free software movement will recognize the OGL as similar to free software licenses. Paralleling open source, the idea in games is called open gaming. The intent of d20 and the OGL was to make role-playing games more accessible to new players. The hope was that if other game designers took up the d20 system, there would be a proliferation of games with similar rules. So far, a number of third parties have published d20 System games under the OGL.
The rules for the d20 System are defined in the System Reference Document (currently version 3.5), which may be copied freely or even sold. The System Reference Document is essentially the Dungeons & Dragons 3rd Edition Player's Handbook stripped of description and flavour-text.