To create Façade, 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.
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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 Façade 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 Façade-like content.
Façade and its technologies are owned by Procedural Arts, a new studio we've started. If you're
interested in commercial possibilities of the Façade
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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