Frank Petzold

Graph-based retrieval of building information models for supporting the early design stages

Building information modeling (BIM) principles are transforming todays communication and working processes in the field of construction, however the early design phases are only rarely supported and information technology is therefore not exploited to its full potential. The early design phases are characterized by an iterative process of searching for plausible solutions. A common approach is to refer to similar examples, which are conventionally found using keyword-based search strategies.To this end we propose a method for indexing spatial configurations along with a sketch-based input method for search strategies that uses so-called semantic fingerprints of buildings. The topology of spatial configurations is extracted from building information models and represented as graphs. For both building information models and the user sketches, the extracted graphs are used as the basis for a subgraph-matching algorithm facilitating an intuitive novel query method for researching similar reference examples. The system is able to present corresponding existing solutions to even rudimentary sketches or fragments of a design idea. In addition to graph matching and sketch-based interaction, more recent BIM-based approaches are also taken into account.

Automatic analysis and sketch-based retrieval of architectural floor plans

The contribution of this article is twofold. First, we propose a sketch-based system, namely the a.SCatch system, for querying a floor plan repository. Second, for generating such a repository, a novel complete system for floor plan analysis is presented. The latter system extracts the semantics from existing floor plans. We introduce novel preprocessing methods, e.g., the differentiation between thick, medium, and thin lines and the removal of components outside the convex hull of the outer walls. Especially, the use of the convex hull increases the performance of the final system. The a.SCatch system enables the user to easily access knowledge from past projects. The user searches for semantically similar floor plans just by drawing parts of the new plan. An algorithm extracts the semantic structure sketched by the architect on DFKIs Touch &Write table. Finally, the extracted structures are compared using the graph matching, and the most similar one is retrieved. In our experiments for floor plan analysis on a reference data set we compare our approach to other approaches available in the literature. We show that our floor plan analysis system outperforms previous systems. Also the performance of the sketch recognition system is quite high. Overall, the performance of the floor plan analysis, as well as of the retrieval, is already good for the use in practice.

Spatial Augmented Reality for Architecture — Designing and Planning with and within Existing Buildings

At present, more than half of all building activity in the German building sector is undertaken within existing built contexts. The development of a conceptual and technological basis for the digital support of design directly on site, within an existing building context is the focus of the research project “Spatial Augmented Reality for Architecture” (SAR). This paper describes the goals achieved in one aspect of the project: the sampling of colors and materials at a scale of 1:1 using Augmented Reality (AR) technologies. We present initial results from the project; the development of an ad-hoc visualization of interactive data on arbitrary surfaces in real-world indoor environments using a mobile hardware setup. With this, it was possible to project the color and material qualities of a design directly onto almost all surfaces within a geometrically corrected, existing building. Initially, a software prototype “Spatial Augmented Reality for Architecture-Colored Architecture” (SAR-CA) was developed and then assessed based on evaluation results from a user study.

Migrating the Classical Pen-and-Paper Based Conceptual Sketching of Architecture Plans Towards Computer Tools - Prototype Design and Evaluation

While computer-based design tools are widely used in architecure during late design phases for creating final floor plans, early design phases usually still take place in a traditional manner, using pen, paper and scissors. At the beginning of these phases, there is often only a rough idea of how a building should look like. Viewing existing floorplans of similar buildings can help an architect in his/her creative work, but searching for those plans manually is very time-consuming. Automated tools for searching similar floor plans could help to lower the amount of time needed for such investigations tremendously. In order to employ such search mechanisms, proper user interfaces are needed that fit to the architect’s working process. These interfaces should be useable easily and naturally, requiring less initial training. They should be capable of creating search requests that can be processed by the attached search mechanism. In this article, we describe two different user interfaces to serve this purpose. We describe their structures and interaction principles. Afterwards we show their general usability and user acceptance by the means of a users study.

Thinking With Containers: A Multi-Agent Retrieval Approach for the Case-Based Semantic Search of Architectural Designs

To provide the retrieval of information, that can be considered useful during the design conceptualization process, with advantages of distributed artificial knowledge, an approach, that distributes retrieval-related and knowledge maintaining tasks among autonomously working and case-based self-learning agents and agent groups, can be used. In this work we present the distributed retrieval system MetisCBR for the architectural design domain, where agents work in groups (containers) on resolving of user queries built with a semantic description model Semantic Fingerprint. The main aim of our approach is to carry out a basis for a considerable retrieval tool for architects, where the combination of case-based reasoning and multi-agent methods helps to achieve valuable and helpful search results in a comprehensive building design collection.

Fast subgraph isomorphism detection for graph-based retrieval

In this paper we present a method for a graph-based retrieval and its application in architectural floor plan retrieval. The proposed method is an extension of a well-known method for subgraph matching. This extension significantly reduces the storage amount and indexing time for graphs where the nodes are labeled with a rather small amount of different classes. In order to reduce the number of possible permutations, a weight function for labeled graphs is introduced and a well-founded total order is defined on the weights of the labels. Inversions which violate the order are not allowed. A computational complexity analysis of the new preprocessing is given and its completeness is proven. Furthermore, in a number of practical experiments with randomly generated graphs the improvement of the new approach is shown. In experiments performed on random sample graphs, the number of permutations has been decreased to a fraction of 10−18 in average compared to the original approach by Messmer. This makes indexing of larger graphs feasible, allowing for fast detection of subgraphs.

Extending the Flexibility of Case-Based Design Support Tools: A Use Case in the Architectural Domain

This paper presents results of a user study into extending the functionality of an existing case-based search engine for similar architectural designs to a flexible process-oriented case-based support tool for the architectural conceptualization phase. Based on a research examining the target group’s (architects) thinking and working processes during the early conceptualization phase (especially during the search for similar architectural references), we identified common features for defining retrieval strategies for a more flexible case-based search for similar building designs within our system. Furthermore, we were also able to infer a definition for implementing these strategies into the early conceptualization process in architecture, that is, to outline a definition for this process as a wrapping structure for a user model. The study was conducted among the target group representatives (architects, architecture students and teaching personnel) by means of applying the paper prototyping method and Business Processing Model and Notation (BPMN). The results of this work are intended as a foundation for our upcoming research, but we also think it could be of wider interest for the case-based design research area.

Tangible Mixed Reality On-Site: Interactive Augmented Visualisations from Architectural Working Models in Urban Design

The consequences of architectural planning and design decisions made in the early design phases are hard to foresee. While professionals are used to reading plans and understanding architectural models, most laypeople are not familiar with their abstractions. This can lead to misinterpretations and misunderstandings between the different participants in the design process, especially in complex building situations, and decisions can be made or rejected that can have far-reaching consequences for the remainder of the project.

Comparative Evaluation of Rule-Based and Case-Based Retrieval Coordination for Search of Architectural Building Designs

To support the early conceptualization phase in architecture with computer-aided solutions, in particular, with retrieval systems that can find similarly structured building designs in comprehensive collections of such designs, a number of approaches were presented to date. In the Metis project two retrieval coordination approaches (coordinators) were developed to govern the search of similar (sub-)structures of architectural designs. The main task of both coordinators is to select the retrieval method that is appropriate for the given user query. First approach is a standalone service that uses rules only to coordinate the retrieval and can use subgraph matching and database search methods, whereas the second one is rule- and case-based and is part of a distributed system for case-based retrieval of architectural designs. We compared both coordinators in a user study to find out which strengths and weaknesses both coordinators currently possess, and for which retrieval scenarios of the architectural conceptualization phase they could be appropriate. The results showed that the complexity of the particular scenario and the purpose of search are the main points that differentiate both coordinators. The rule-based coordinator performed better when a search for exact (sub-)structures was required, whereas the rule- and case-based coordinator is appropriate for queries aimed to be used for exploration and general search for inspiration. Visualization of the results of both coordinators is in need of improvement.

Demo] On-Site Augmented Collaborative Architecture Visualization

The early design phase for a new building is a crucial stage in the design process of architects. It has to be ensured that the building fits into the future environment. The Collaborative Design Platform targets this issue by integrating modern digital means with well known traditional concepts. Well-used styrofoam blocks are still cut by hand but are now tracked, placed and visualized in 3D by use of a tabletop platform and a TV screen showing an arbitrary view of the scenery. With this demonstration, we get one step further and provide an interactive visualization at the proposed building site, further enhancing collaboration between different audiences. Mobile phones and tablet devices are used to visualize marker-less registered virtual building structures and immediately show changes made to the models in the Collaborative Design laboratory. This way, architects can get a direct impression about how a building will integrate within the environment and residents can get an early impression about future plans.