Aarhus School of Architecture / Design School Kolding / KADK An Automated Approach to the Generation of Structured Building Information Models from Unstructured 3d Point Cloud Scans Tamke,

In this paper we present and evaluate an approach for the automatic generation of building models in IFC BIM format from unstructured Point Cloud scans, as they result from 3d­laser scans of buildings. While the actual measurement process is relatively fast, 85% of the overall time are spend on the interpretation and transformation of the resulting Point Cloud data into information, which can be used in architectural and engineering design workflows. Our approach to tackle this problem, is in contrast to existing ones which work on the levels of points, based on the detection of building elements, such as walls, ceilings, doors, windows, and spaces and the relation between these. We present use cases with our software prototype, evaluate the results, and discuss future work, that will bring the research further towards the aim to create automatically semantic links between the conception of building design in BIM and simulations with the build environment. K eywords : BIM, Point Clouds, 3D Scanning, Evaluation, Computational Methods, Machine Learning, Semantic Web 1. Introduction Today, the largest part of work conducted in the Architectural and Engineering Community (AEC) involves the existing building stock. In Europe, over 80% of all buildings are older than 25 years and in need for adaption to contemporary levels, especially regarding energy consumption[1]. Most of these buildings are bare of up to date documentation of their current state and need to be measured and documented in a way that allows building owners, architects, and engineers to assess the state and start their design and planning tasks. 3D laser scans of building structures are today quickly executed and precise which allows for an almost real­time monitoring of construction and provides an unprecedented base for further planning in the existing building stock. In industrialised countries, this task is executed increasingly [2,3,4] wíth tools and communication processes which follow the Building Information Modelling paradigm [5]. Copyright © 2016 by M. Tamke, H. L. Evers, M. Zwierzycki, R. Wessel, S. Ochmann, R. Vock, R. Klein Published by the International Association for Shell and Spatial Structures (IASS) with permission. Proceedings of the IASS Annual Symposium 2016 Spatial Structures in the 21st Century However, current BIM software and workflows are not ready to integrate the output of 3d scans, namely Point Clouds. Due to their oftentimes large size, handling point clouds is per se cumbersome. Additionally, they do not provide the structured information that AEC requires for planning. A transfer of the unstructured point clouds into machine­readable definitions of spaces and building elements (Fig.1) and a subsequent step of annotating this data with semantic information, such as materials, areas and connectivity of spaces is therefore indispensable. This post processing and BIM modeling currently requires expert knowledge and takes about 85% of the overall required time [6]. The challenge in the use of 3d scanning technologies has shifted from data acquisition to its interpretation and the subsequent reconstruction of a BIM model from it.