• Game_Technology
• Tutenel

Semantics in game worlds

Tim Tutenel

Objects in game worlds lack most semantic information: they consist of little more than their geometric models. Additional information is usually scripted in an application specific, ad hoc manner, limiting interactions to what is defined by the designer.

A more generic way of specifying and maintaining semantics could improve both the design and runtime phase of a virtual world. During design, semantic information can be used for assisting manual editing in an intelligent way, ranging from constraint-based automatic object distribution (e.g. believable, functional layout of chairs, tables, plates etc. in a dining room) to maintaining relation constraints between objects (e.g. a bridge that is coupled to two road segments will remain connected when one of the segments is moved).

Interrelationships and constraints between objects are used in a semantic layout solving approach to procedurally generate realistic and valid virtual world scenes. The contents and structure of a certain class of scenes is defined in a semantic scene descriptions. These descriptions contain entities defining what type of objects are necessary or plausible in the described scene, each with a quantity and optionally some scene-specific interrelationships. Some example scenes based on descriptions for a factory floor and an office space can be seen below.

The vocabulary from our semantic library, is utilized to create queries in these descriptions, but can also be used at runtime, e.g. to plan goals for AI characters in a more generic fashion or to handle interaction with the player. A previous M.Sc. project focused entirely on semantics for player interaction in the form of services.

Currently, research is being performed in using the semantics to maintain consistency in generated scenes after manual edits have been performed. This involves re-applying relationships after changes have been made to the scenes as well as blending fixed and regenerated scene parts.

In this research project, a B.Sc. project was undertaken to enhance both the visual quality and realism of the generated scenes by applying a finishing pass of effects that change the look of the scene using procedural filters, e.g. adding dust and dirt to age objects or snow to the rooftops during winter.

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