Towards a client-oriented integration of construction processes and building GIS systems

Highlights

• Approach to manage and visualize nD information in AEC processes over buildings.

• Based on an IFC model arising from COLLADA and MPP files following a BIM methodology.

• Evaluates the results by Web3D Advance Visualization using Open Source technologies.

• Solution has been implemented using the WebGL rendering for Advance Visualization.

• 3D building model can be inspected remotely and simulate the construction evolution.

Abstract

BIM (Building Information Modelling) methodology allows sharing the information about the same construction between the involved stakeholders. The same building will be affected by different AEC (Architectural, Engineering and Construction) processes. Some n-dimensional extensions have been recently proposed in the literature. The fourth dimension of BIM represents the planning of the building phases. This dimension can be used to simulate the building state at a fixed point in time, as a snapshot. This paper shows the development of a Web3D visualizer, which integrates 3D documentation with building planning following the BIM methodology using just Open Source software. Our main contribution is the merging of project planning and 3D documentation into a single model, which can be visualized in a modern web browser without plugins. Different construction phases are visualized in a unique and shared global model, which is updated along execution time according to a well-specified visual planning. Our application allows identifying bottlenecks or delays in processes with a status indicator, which is updated along time. Filtering processes allows select the most meaningful aspects for each stakeholder to improve management and satisfaction for final client. The use of Open Source software and standard protocols and technologies allows a wide spread and rapid adoption of the solution, which can be easily extended to support future use cases.

Introduction

This work aims to establish a feedback between the common practices of technicians in AEC and its computer implementation in terms of KMS (Knowledge Management Systems). To achieve this goal, we have developed a methodology which combines structural and functional aspects. The former ones are described in terms of objects and relations, whereas the latest one are described in terms of generalized functions which act on structural aspects or a symbolic representation given by graphs.

In this section, we provide an adaptive representation of a flowchart in terms of basic units (cells) which are grouped in cubic complexes by means of simple operators (join and intersection, e.g.). The representation for large elements is given in terms of nodes, edges and “faces”, which are compatible with usual methods for structural computations in terms of finite elements. Beyond the formalism, our methodology provides a modular support to update information, insert and evaluate modifications (usually forbidden in constructive processes).

Visualization tools are focused towards a better understanding of reality and, consequently, they involve to cognitive science and its improvement through interaction with smart interfaces. Knowledge improvement is supported by the representation of physical objects, but they must be accompanied by a semantic which gives sense to the objects. Semantics involve to the meaning which must be described in terms of context; beyond structural aspects (involving objects and relations), it includes functionals to be evaluated on structural aspects.

The most common representations use geometric primitives and basic operations between them. Furthermore, our approach incorporates (1) a symbolic representation for constructive processes and (2) a support to perform computations linked to different kinds of functional defined on the structural model. Hence, our representation is compatible with a modular approach for design, implementation, execution and tracking objects and relations. It incorporates semi-automated procedures from the design phase till evaluation and tracking after ending the work. The proposed symbolic representation is given by an expandable dual graph of a 2D/3D representation which encodes the underlying semantics (interconnected spaces), and provides a guideline for representing different stages and building processes involving AEC environments.

Semantics can be described in terms of an ontology which is understood as a knowledge representation. Unfortunately, there is no a unique ontology, and it is necessary to develop methods and implement strategies for “connecting” different ontologies, with different strategies which can be labeled as fusion vs alignment. Fusion of ontologies is more expensive from the computational viewpoint; thus along last years, there is an increasing literature about aligning ontologies (see [1], [2]).

3D GeoInformation is coded in terms of a three-dimensional representation which is compatible with any kind of geometric principles involving the design. Furthermore, it grows along the work execution, according to a generative grammar beyond simple shapes (cuboids and their components) which are used for representing interconnected spaces. Indeed, the composition principles for basic geometric primitives can be replaced by any other topologically equivalent primitives if one replaces linear by more general continuous maps for matching together primitives.

nD GeoInformation is constructed as special case of nD Information Systems, i.e. in terms of a collection of layers involving different attributes and/or properties related with installations and interaction with a changing environment. Supplementary dimensions can involve to time, temperature, costs or any scalar or vector functional. Color maps allow to visualize changes involving these functionals which are superimposed to the original volumetry. In particular, the proposed representation provides support for nD GeoInformation which is stored in terms of different layers which are superimposed according to AEC needs.

In this work, we have developed some visualization tools for GeoInformation involving AEC environments arising from the Web3D. They are focused towards the design and modeling of evolving 3D contents inside the browser which allows their integration with other HTML elements. More specifically, we have developed an HTML5 web based application called 3DSIMOS to visualize different construction stages according to a well specified planning. Our application is able of rendering complex models in the browser without additional plug-ins such as Flash thanks to the use of the WebGL technology to render 3D graphics inside the browser. Additionally, it support advanced visualization methods applied to Building Information Modeling (BIM) processes to perform computations involving the elements included in the represented scene [3].

The rest of the paper is organized as follows. Section 2 summarizes the background of the paper and the state of the art regarding GeoInformation and visualization. This section also proposes several natural extensions concerning to 3D Georeferencing. A sketch of our approach to nD GeoInformation systems is introduced at the end of this section too. Section 3 states the problem and provides a simplified explanation (mathematical details have been minimized) to the mathematical framework which supports data management and visualization. Section 4 includes details about design and implementation of our software application to evaluate our approach. This section shows a general overview of the application linked to the client more meaningful requirements and features from a point of view of software engineering. The end of this section shows the results which have been evaluated over our own Fallingwater showcase which has been specially developed for this demonstration. Finally, the last section highlights some thought-provoking conclusions and challenges to be solved in the next future.