Building Knowledge about BuildingsMatt Young and Eyal AmirUniversity of Illinois, Urbana-Champaign

The Problem• Need a way to represent

information about buildings.

• A wealth of information exists in floor plans, but what information do we need? How to encode it?

Our Goals• A general framework for

representing buildings which is:• Simple enough to add

data quickly/automatically.• Complete enough to

accurately represent the structure of a building.

• Able to answer queries regarding that structure.

Overview• Previous Work• Overview of Our Language• Comparison with Current Technology• Other Applications• Future Work

Previous Work - Cyc• Contains a “Building” constant, defined as “A

specialization of both FixedStructure and HumanShelterConstruction.”

• By following assertions through the hierarchy, we can learn certain information about a building such as what rooms it contains, how many levels it has, etc.

• However, there is no structured presentation of how things are connected together, how the building is actually constructed.

Previous Work - IFC Data Model• International standard for

architectural firms, CAD developers, and construction companies.

• Very detailed information about building construction.

• However, also contains a great deal of information about processes, analysis, CAD data, etc.

• Also, it is inconsistently implemented.

Our Solution• A language designed specifically to capture

only the structure of a building.• Encoded as an ontology in OWL DL, for ease of

use with the Semantic Web, and (hopefully) full decidability on inference.

Language – General Classes• Classes define different

features of a Building.• Four main classes• Building• External_Feature• Internal_Feature• Material

• Subclasses define distinct feature types.

Language - Properties

• Properties define relations between features.

• Most are defined symmetrically, for strong connectedness.

Language - Assertions

• Assertions enforce proper construction of buildings.• Ensure that certain properties must be filled with some

value (or possibly more than one value).• There are no value restrictions.

Language - Specialization• Language can be extended

with subclasses of the general classes define to subtypes of each feature.e.g. House is a subtype of Building, Bedroom is a subtype of Room.

• Subtypes are defined by additional restrictions, some of which may be value restrictions.

• Subtypes can also be inferred, but this slows down search considerably.

Language - Limitations• No spatial information (size, shape).• No information about environment surrounding

building.• Some features are difficult to encode:• Features serving multiple purposes (e.g. A roof also

serving as a wall, such as in an A-frame).• Features which are both external and internal.

Comparison with Current Technology

Architectural Feature Houseplans.com

Our language

# of Bedrooms/Baths Yes Yes

# of Floors Yes Yes

Includes certain room type Yes Yes

Square footage Yes No

Has X room on Y floor No Yes

Has X room connected to Y room No Yes

# of exits from each room No Yes

Other Applications• Find paths out of buildings (fire escapes).• Complete a building floor plan given a partial

encoding of the building.• Use a knowledge base encoded in this

language to categorize buildings given partial information about them.

Future Work• Adding spatial information without losing

decidability.• Adding encoding for surrounding environment

and for objects within the building to create a full virtual world space.

• Encoding data automatically from floor plans or IFC models.

Conclusion

• Special thanks to Eyal for all his help and guidance.

• Questions / Comments ?