Historic Building Information Modelling – Adding intelligence to laser and image based surveys of European classical architecture

Abstract

Historic Building Information Modelling (HBIM) is a novel prototype library of parametric objects, based on historic architectural data and a system of cross platform programmes for mapping parametric objects onto point cloud and image survey data. The HBIM process begins with remote collection of survey data using a terrestrial laser scanner combined with digital photo modelling. The next stage involves the design and construction of a parametric library of objects, which are based on the manuscripts ranging from Vitruvius to 18th century architectural pattern books. In building parametric objects, the problem of file format and exchange of data has been overcome within the BIM ArchiCAD software platform by using geometric descriptive language (GDL). The plotting of parametric objects onto the laser scan surveys as building components to create or form the entire building is the final stage in the reverse engineering process. The final HBIM product is the creation of full 3D models including detail behind the object’s surface concerning its methods of construction and material make-up. The resultant HBIM can automatically create cut sections, details and schedules in addition to the orthographic projections and 3D models (wire frame or textured) for both the analysis and conservation of historic objects, structures and environments.

Introduction

In this paper Historic Building Information Modelling (HBIM) (Murphy et al., 2009) is described beginning with a short review of literature concerning parametric modelling and Building Information Modelling (BIM). The methodology for constructing a library of interactive parametric objects based on historic architectural data is presented illustrating the sourcing and analysis of historic architectural data and how the parametric architectural elements are coded using geometric descriptive language GDL. The building of the library is followed by an example of mapping the interactive parametric objects onto the laser scan and image survey data, resulting in the automation of survey engineering drawings and schedules, demonstrating the complete HBIM process. In conclusion, the evaluation process, which is, now under-way is outlined; initial results indicate the potential for HBIM for the conservation of historic structures and environments.

Historic Building Information Modelling (HBIM) is a novel solution whereby interactive parametric objects representing architectural elements are constructed from historic data, these elements (including detail behind the scan surface) are accurately mapped onto a point cloud or image based survey. The architectural elements are scripted using a geometric descriptive language (GDL). The design and detail for the parametric objects are based on architectural manuscripts ranging from Vitruvius to Palladio to the architectural pattern books of the 18th century. The architecture of the renaissance introduced and documented advanced scientific rules for the production of architectural elements, which support the design of parametric models. The use of historic data introduces the opportunity to develop detail behind the object’s surface concerning its methods of construction and material makeup In the final stage of the HBIM process, the prototype libraries of parametric objects (see sample of library in Fig. 11) are mapped onto the point cloud and image survey data using a system of cross software platform management. Full engineering drawings orthographic, sectional and 3D models can then be automatically produced from the Historic Building Information Model.

Historic Building Information Modelling has been described in previous work (Murphy et al., 2009) which concentrated on the identification of data collection using laser scanning and the processing of the scans in order to isolate and test the most suitable survey products for further modelling in HBIM. These were identified as segmented point cloud sections and ortho-images, used as frameworks for plotting parametric. The concept for designing library objects in GDL was introduced in addition to the design of a plotting procedure. The motivation for this work has evolved from attempts to automate conservation documentation in the form of engineering drawing and schedules from laser scan and image based surveys of historic structures. In the field of practice, particularly our work with historic structures in Ireland, it emerged that conservation experts found it difficult to use point cloud survey data as a basis for developing conservation documentation. With the result that much of the valuable research in the areas of remote sensing for architectural heritage was limited as a visualisation tool whereas its potential to automate documentation for the whole conservation cycle for historic structures is not yet realised. In this paper the following new and additional aspects are developed for modelling architectural heritage:

• A historic framework for building a parametric library of architectural elements is proposed, through assessing the evolution of architectural manuscripts in order to map and identify significant rules that represent a wide range of classical buildings, and can be applied to computer modelling. Secondly the interpretation and understanding of these rules is essential and can be more easily adapted from the architectural pattern books which emerged after the renaissance and beginning of the enlightenment period of the 17th and 18th centuries, these patterns are interpreted for both geometric shapes and non uniform shapes.

• The development of parametric and shape rules to re-produce the classical elements detailed in the pattern books using GDL is presented, these are illustrated in Fig. 2, Fig. 3, and described in a sample code. The shape commands and new library of primitives allow for all configurations of the classical orders in relation to uniform geometry. Non-uniform and organic shapes are developed in GDL through a series of procedures attempting to maximise parametric content of the objects (see Fig. 4, Fig. 5). These shapes are stored as individual parametric objects or combined to make larger objects in a library and when used in the HBIM platform can be varied and deformed to match their requirements. The library range and size is best illustrated by their use in models, this range is illustrated in Fig. 6, Fig. 9, Fig. 10, Fig. 11.

• The problems of plotting onto point cloud and image survey data is addressed and solutions are proposed and tested, the fact that Building Information Modelling generates its 3D models through plotting in 2D onto different planes, requires that survey data be segmented and processed in 2D in the BIM environment. This has been solved through a series of procedures, see Fig. 7. Secondly objects are re-generated and deformed through changing parameters and this is based on numeric data. To facilitate this, a photo scaling application, which is web-based, has been developed and is used for plotting and measuring distances and angular values using two-dimensional segmented data. This automates the production of numeric parametric data for revising and plotting the library objects onto the laser survey data.

• Finally a design for end user scenario testing is proposed to assess the suitability of HBIM as a tool for the automation of engineering drawings for the conservation process.

The HBIM approach is new as most applications of Building Information Modelling are applied to designing new buildings and new innovations that are concentrated around plug-ins for energy, structural, economic analysis and scheduling of components as an addition to new architectural design. With the exception of (Fai et al., 2011), very little work has been done in relation to modelling historic buildings and also generating BIM models from laser scan survey data. Their work, concentrated on the problems associated with combining laser scanning and BIM through plotting generic library objects onto the laser scan-based survey in a BIM environment. This approach did not include the creation of parametric libraries or improved plotting of objects onto the scan surveys. The advantages of HBIM over other modelling approaches is that the end result provides automated documentation in the form of engineering drawings for precise conservation of architectural heritage. This is in contrast to highly sophisticated visualisation products developed from procedural and other parametric modelling approaches whereby the main product is a visualisation tool. HBIM differs from these approaches, as the product is the creation of full 3D models including detail behind the object’s surface concerning its methods of construction and material makeup. In addition 3D documentation is produced which includes orthographic projections, sections, details and schedules (energy, cost decay etc.), adding intelligence to point cloud data.

Using historic data to re-create the past or to restore or conserve historic artefacts and buildings is common in the wider area of conservation (ICOMOS, 2011) and is a wide area of research. Within both research areas of procedural and parametric modelling of architectural heritage the use of architectural knowledge to inform the creation of models is now becoming a common part of a design approach (Chevrier et al., 2010, Chevrier et al., 2009, De Luca et al., 2011, Muller et al., 2006, Wonka et al., 2003). While these works inform the HBIM approach they differ in their analysis of historic architectural data. HBIM focuses on the emergence of architectural pattern books to define architectural rules and detail. In addition a narrative is presented, which defines the evolution and form of European classical architecture for computer-based modelling. The aim of producing conservation documentation as opposed to sophisticated visualisation models requires different levels of accuracy especially in the specification of construction detail behind the scan surface. Wider and deeper historic sources in addition to different software tools are therefore required.