Kui Yue

The ASDMCon Project: The Challenge of Detecting Defects on Construction Sites

Techniques for three dimensional (3D) imaging and analysis of as-built conditions of buildings are gaining acceptance in the architecture, engineering, and construction (AEC) community. Early detection of defects on construction sites is one domain where these techniques have the potential to revolutionize an industry, since construction defects can consume a significant portion of a projects budget. The ASDMCon project is developing methods to aid site managers in detecting and managing construction defects using 3D imaging and other advanced sensor technologies. This paper presents an overview of the project, its 4D visualization environment, and the 3D segmentation and recognition strategies that are being employed to automate defect detection.

Integration of knowledge-based and generative systems for building characterization and prediction

Abstract This paper discusses the integration of knowledge bases and shape grammars for the generation of building models, covering interaction, system, and implementation. Knowledge-based and generative systems are combined to construct a method for characterizing existing buildings, in particular, their interior layouts based on exterior features and certain other parameters such as location and real dimensions. The knowledge-based model contains information about spatial use, organization, elements, and contextual information, with the shape grammar principally containing style rules. Buildings are analyzed and layouts are generated through communication and interaction between these two systems. The benefit of using an interactive system is that the complementary properties of the two schemes are employed to strengthen the overall process. Ontologies capture knowledge relating to architectural design principles, building anatomy, structure, and systems. Shape grammar rules embody change through geometric manipulation and transformation. Existing buildings are analyzed using this approach, and three-dimensional models are automatically generated. Two particular building types, the vernacular rowhouse and high-rise apartment building, both from Baltimore, Maryland, are presented to illustrate the process and for comparing the utilized methodologies.

Ontologies and Shape Grammars: Communication between Knowledge-Based and Generative Systems

This paper discusses information flow between knowledge-based models and shape grammars for generation of building designs, explaining the interaction, sys-tem and implementation. The benefit for using the interactive system is that the complementary properties of the two schemes are used to strengthen the overall process. Shape grammar contains rules about the geometric organization, while knowledge-based model supports the contextual information.

A Technique for Implementing a Computation-Friendly Shape Grammar Interpreter

We are investigating how to determine the interior layout of buildings given three pieces of information: its footprint; a reasonably complete set of exterior features; and a shape grammar that describes the building style and hence, the building [1]. We have developed an approach that relies on the fact that, when applied exhaustively, a shape grammar generates, as a tree, the entire layout space of a style. The approach begins with estimating a partial layout, by resolving constraints on the input features. From this estimation, further spatial and topological constraints are extracted. These constraints are then used to prune the layout tree. The layouts that remain correspond to the desired outcomes. Spaces (rooms) are central to buildings; whence, to shape grammars that describe building styles. Such grammars generally start with a rough layout; details, such as openings and staircases, are added at a subsequent stage. There are two main ways of generating a layout: space subdivision, e.g., as in the rowhouse grammar (see sequel), and space aggregation, e.g., as in the Queen Anne grammar [2]. Combination of the two ways is possible. Consequently, here, shape rules tend to add a room, partition a room, additionally to refine a partial layout by inserting features such as doors, staircases, etc.

Developing a tractable shape grammar

Previously, we examined tractable parametric shape grammars and developed a general paradigm for implementing classes of such grammars. A tractable shape grammar has polynomial computing complexity, and is specified in a way that is readily transformable to a computer program. By contrast, traditionally, shape grammars have been typically developed without a computer implementation in mind, either requiring ambiguity to be clarified, or it is hardly possible for the grammar to be implemented by a polynomial algorithm. Each tractable shape grammar is tied to a particular framework, which is backed by a data structure and supports a metalanguage. In this paper we illustrate the development of tractable shape grammars by transforming a shape grammar developed, essentially, in traditional fashion for the Baltimore rowhouse. The development is for a specific application context— to determine the interior layout of a building given its external features—and the process serves as a general strategy for developing tractable shape grammars.