(c) 2005-6 Procedural Arts



Fašade Technology


To create Fašade, we developed several innovative technologies, including:

• ABL (A Behavior Language), a special purpose programming language (technically, a reactive planning language), designed specifically for authoring personality rich, emotive autonomous characters. This language builds upon pioneering work by A. Bryan Loyall, Joseph Bates and the rest of Oz Project team at Carnegie Mellon University.

• A drama manager that dynamically sequences units of story (dramatic beats) in response to the history of the player's interaction.

• A custom rule language for authoring robust natural language understanding rules. This NLU language is implemented on top of
Jess, a rule engine implemented by Ernest Friedman-Hill at Sandia National Laboratories.

• A discourse management framework for keeping track of multiple conversational threads and deciding which response is appropriate in the current context. This is built on top of Jess as well.

• A custom non-photorealistic animation engine that supports fully procedural facial expressions. Implemented in C++ using OpenGL.


In addition to developing these custom languages and technologies, we have also developed extensive idioms for authoring procedural content within our architecture. These idioms include ways of organizing character behavior, including dramatic dialog, so that multiple actions and conversational threads can dynamically mix together, ways of authoring beats (units of story) so that they can be dynamically sequenced in multiple orderings, and ways of structuring our natural language understanding rules so that multiple tiers of rules work together to recognize common synonyms, idiomatic expressions, and more complex syntactic expressions.

Our
publications page describes many of these technologies in detail.

These technologies made Fašade possible. But, they are not end-user authoring solutions for creating interactive stories. Our current tools and authoring techniques require programming expertise; in fact, even expert programmers familiar with language such as C++ and Java will have to learn new ways of thinking about programming to program in ABL. For this reason, we are not publicly releasing the authoring tools at this time, though we will be working towards the future release of higher-level authoring tools that enable writers and artists to create Fašade-like content.

Fašade and its technologies are owned by
Procedural Arts, a new studio we've started. If you're interested in commercial possibilities of the Fašade technologies, please email us at the contact info found at Procedural Arts.

There will be an academic-use release of the ABL character language from the
Experimental Game Lab at Georgia Tech in the near future.

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