DELIVERABLE REPORT DELIVERABLE N 0 : D2.5 DISSEMINATION LEVEL: PUBLIC REPORT ON IMPROVED USAGE OF BIM TECHNOLOGY

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1 DELIVERABLE REPORT DELIVERABLE N 0 : D2.5 DISSEMINATION LEVEL: PUBLIC TITLE: REPORT ON IMPROVED USAGE OF BIM TECHNOLOGY DATE: 18/04/2016 VERSION: FINAL AUTHOR(S): LÉON VAN BERLO (TNO) MARJOLEIN VAN DER JAGT-DEUTEKOM (TNO) RONALD VAN WALSUM (ARCADIS) WOLFRAM KLEIN (SIEMENS) INGO MÜLLERS (SCHUESSLER-PLAN) REVIEWED BY: APPROVED BY: MARJOLIJN VERSTEEGDEN (ARCADIS) WOLFRAM KLEIN (SIEMENS) COORDINATOR ANS VAN DOORMAAL (TNO) GRANT AGREEMENT NUMBER: PROJECT TYPE: FP7-SEC RESILIENCE OF LARGE SCALE URBAN BUILT INFRASTRUCTURE CAPABILITY PROJECT PROJECT ACRONYM: ELASSTIC PROJECT TITLE: ENHANCED LARGE SCALE ARCHITECTURE WITH SAFETY AND SECURITY TECHNOLOGIES AND SPECIAL INFORMATION CAPABILITIES PROJECT START DATE: 01/05/2013 PROJECT WEBSITE: TECHNICAL COORDINATION TNO (NL) ( PROJECT ADMINISTRATION UNIRESEARCH (NL) (

2 Executive Summary The term BIM is used very broad. It stands for Building Information Modelling ; sometimes also referred to as Building Information Management. BIM is about data. It is a collection of virtual objects with properties and relations. Because a computer has semantic awareness of the objects, intelligent operations can be performed on the data. The richer and more semantic the dataset, the more intelligent the operations can be. The ELASSTIC BIM concept consists of three main clusters of technology: - Building Information - Simulation models - Sensor information The ELASSTIC concept is about the communication between these three main technology groups. A fourth technology called Multi Criteria Analyses (MCA) is providing the end-user the interface to evaluate safety and security of the building design. The concept is best described with an example. Let s focus on the case of a fire in a building. In case of a fire in a building, the sensors from the Building Management System (BMS) pick it up. The BMS probably responds with the classic sprinkler system. A notification of the fire is also send to the evacuation simulation. The location of the fire, smoke and maybe intensity are available data at this moment in the process. With advances in building management systems the number of people and their location might also be available as data. The evacuation simulation calculates the most effective evacuation route for the people in the building. To do this, it needs to calculate the spread of the fire so it also triggers the fire simulation. For these simulations information about the building is needed. This data comes from the (static) BIM. In case, parts of the building are destroyed, even this new information is available in BIM and have to be read by the BMS. When the BIM data shows installations with high risk of FINAL 2

3 explosions, the explosion simulation can be triggered. The structural integrity of the building might also be evaluated due to the effects of the fire and/or explosions. The most effective evacuation route, due to the recent state of the building, is send to the building management system. By using signs the people in the building can be evacuated via the safest route in the most effective and efficient way. When people don t use the suggested route, sensors (like cameras) can pick up this deviation and start a new simulation. Resulting in a recalculated optimum evacuation route that is send to the building management system. Other information from sensors can also influence the process flow. For example when walls break down due to fire; the BIM data set gets updated and this new dataset is used as the base for evacuation simulation. In this case new evacuation routes may come available. Or when parts of the building won t provide structural safety anymore (found by a combination of sensors in load bearing columns and beams) this part might be prioritized in the evacuation (and the BIM data updated). To get this theoretical idea into practice, the ELASSTIC project was started. During this project we tried to implement the concept with open source and closed tools, simulation models and open data standards. The research methodology was that of applied research. The project created BIM dataset of a virtual building. The building dataset in ELASSTIC was split into 5 different sections. More on that in the chapter performance. The 5 sections together formed the whole building. Within the 5 sections discipline models where created for the disciplines Architecture, Construction and MEP. The concept of micro-services is used in ELASSTIC to connect the different simulation tools to the BIM data. Every simulation tool should be developed as an online service that is minimal and complete. The interface to the tools should be BIM compatible. The workflow between BIMserver and the simulation models is event driven. Every simulation model can subscribe to events on the used BIMserver in which they have interest. When this event occurs the BIMserver sends a notification of the event to the subscribed simulation service(s). The simulation services most probably run on a separate (remote) server. This server can then perform actions on (using a token FINAL 3

4 as login) and send the results back to the BIMserver, or to any other service. This way a chain of event driven services can be triggered on an event (like new revision ). The simulation models used in ELASSTIC are: - Explosion simulation - Pedestrian stream / Evacuation simulation - Earthquake simulation - Structural simulations - Energy simulations The ELASSTIC BIM concept proved to have great potential to the industry. Due to the automation of simulation models (with or without supporting services) the designer is provided with direct feedback of the performance of the building during the (early) design phase. To optimize the usability of this concept additional features are introduced like model-checking, preprocessing of data (called supporting services in this report), post processing of data (in this project to facilitate the MCA tool), advanced query/filter functions, etc. These additional features facilitate the usability for simulation tools to use the ELASSTIC BIM concept, and BIM in general. FINAL 4

5 Contents Executive Summary... 2 Contents Introduction / background About BIM The Concept and history Data standards BIMserver BIM data in ELASSTIC Analyses of BIM data ELASSTIC technology concept The ELASSTIC BIM concept: Integration of Technologies IT architecture Linking to building Management system and sensor information Design Evaluation Innovation ELASSTIC data flow Simulation models Domain specific requirements Classifications Model view definitions (MVD) Supporting tools BIMserver.org Model checking Data transformation services ELASSTIC BIM gateway Process inside BIMserver Setting up a notification/trigger Process outside BIMserver External service ( bot ) running Query language Remote data coming back Log of ELASSTIC workflow The ELASSTIC setup The ELASSTIC Simulation models Triggering the simulation models Explosion simulation (TNO) FINAL 5

6 1.1.1 IFC model of the building Recognition of different objects and its characteristics Determination of the façade: Results and visualisation Pedestrian stream (Siemens) Earthquake (Schüßler-Plan) Structural simulations Structural design calculation Wind load structural simulation Energy simulation Performance & Usability Levels of geometrical detail (IFC) Scalability of simulations (in relation to process) Visualisation of results Link to MCA Structuring extended data Preprocessing data to facilitate MCA Post processing data to facilitate MCA Observed and potential process innovation Discussion and conclusion Acknowledgment Appendix 1 IFC entities in the ELASSTIC Ribbon model Appendix 2 Event log flow of ELASSTIC BIM gateway Appendix 3 Literature list FINAL 6

7 1 Introduction / background The term BIM is used very broad. It stands for Building Information Modelling ; sometimes also referred to as Building Information Management. The term Building can be seen as a verb. In simple terms BIM is about data. It is a container-term to mark the transformation from a paper/drawings driven industry to a data driven industry. In the base BIM is about data. It is a collective term to highlight the industry s movement from paper based operations to data based operations. BIM equals data. It is a collection of virtual objects with properties and relations. Because a computer has semantic awareness of the objects, intelligent operations can be performed on the data. The richer and more semantic the dataset, the more intelligent the operations can be. The ELASSTIC BIM concept consists of three main clusters of technology: - Building Information - Simulation models - Sensor information The ELASSTIC concept is about the communication between these three main technology groups. The rest of this report will focus on the automation of the communication between these datasets. The dataflow will be described in chapter 5; The BIM data in chapter 6 and the Simulation models in chapter 7. A fourth technology called Multi Criteria Analyses (MCA) is providing the end-user the interface to evaluate safety and security of the building design. The link to the MCA tool is elaborated in chapter 9. FINAL 7

8 The concept is best described with an example. Let s focus on the case of a fire in a building. In case of a fire in a building, the sensors from the Building Management System (BMS) pick it up. The BMS probably responds with the classic sprinkler system. A notification of the fire is also send to the evacuation simulation. The location of the fire, smoke and maybe intensity are available data at this moment in the process. With advances in building management systems the number of people and their location might also be available as data. The evacuation simulation calculates the most effective evacuation route for the people in the building. To do this, it needs to calculate the spread of the fire so it also triggers the fire simulation. For these simulations information about the building is needed. This data comes from the (static) BIM. In case, parts of the building are destroyed, even this new information is available in BIM and have to be read by the BMS. When the BIM data shows installations with high risk of explosions, the explosion simulation can be triggered. The structural integrity of the building might also be evaluated due to the effects of the fire and/or explosions. The most effective evacuation route, due to the recent state of the building, is send to the building management system. By using signs the people in the building can be evacuated via the safest route in the most effective and efficient way. When people don t use the suggested route, sensors (like cameras) can pick up this deviation and start a new simulation. Resulting in a recalculated optimum evacuation route that is send to the building management system. Other information from sensors can also influence the process flow. For example when walls break down due to fire; the BIM data set gets updated and this new dataset is used as the base for evacuation simulation. In this case new evacuation routes may come available. Or when parts of the building won t provide structural safety anymore (found by a combination of sensors in load bearing columns and beams) this part might be prioritized in the evacuation (and the BIM data updated). To get this theoretical idea into practice, the ELASSTIC project was started. During this project we tried to implement the concept with open source and closed tools, simulation models and open data standards. The research methodology was that of applied research. This report lists the results of the applied research, gives an overview of the work that is done and states the research findings and conclusions. FINAL 8

9 2 About BIM 2.1 THE CONCEPT AND HISTORY The term BIM is used very broad. It stands for Building Information Modelling ; sometimes also referred to as Building Information Management. The term Building can be seen as a verb. In simple terms BIM is about data. It is a container-term to mark the transformation from a paper/drawings driven industry to a data driven industry. In the base BIM is about data. It is a collective term to highlight the industry s movement from paper based operations to data based operations. BIM adoption in Europe is very various. Some leading companies use BIM very effective, some countries collectively don t have it on their radar yet. Research shows that BIM is not a hype, but a growing trend that won t go away anymore. In years the whole industry will work with the BIM concept. BIM equals data. It is a collection of virtual objects with properties and relations. Because a computer has semantic awareness of the objects, intelligent operations can be performed on the data. The richer and more semantic the dataset, the more intelligent the operations can be. BIM use started in the 1990s with the release of ArchiCAD from Graphisoft. This was the introduction of the Virtual Building Concept. Instead of using a computer to draw lines for the creation of drawings, a virtual model of a building was created. From this model the drawings were generated. When Autodesk bought Revit, the distribution channel of Autodesk made Revit widely available in the industry. This meant a huge grow for the generic concept of BIM in the industry. In specialized disciplines other tools are very popular. A construction engineer will probably work with Tekla, Scia or (on a lesser scale) Allplan. MEP modelling is done in MagiCAD, StabiCAD or DDS (depending on the region in Europe). Tools like Solibri are very popular to check the quality of the data and to coordinate different discipline models. Most software tools express the same basic concept of BIM: a central model that is used to generate many different views (floorplans, sections, simulations, etc.). At this moment a new wave of online BIM tools is being developed. Online BIM collaboration platforms are the new trend in BIM marketing. The number of BIM tools and start-ups keeps growing daily. There are many misconceptions about BIM. Maybe the biggest misconception is that BIM is centralizing all data of a project into a single data repository. Because most BIM software tools work with a central database that is being used for all features, this concept is being copied on a project scale. The recent rise of online BIM collaboration platforms is feeding this concept. However, many research projects and publications have proven that working with a central data repository is actually decreasing productivity of the project. Working efficiently with distributed data storages is more effective for the project than trying to centralize everything. FINAL 9

10 2.2 DATA STANDARDS Every BIM software tool has its own internal data model. This is a data model that is most effective for the features of that specific tool. The data structure of every BIM tool is therefore different. When designers want to coordinate their designs with each other there needs to be a common data model to map the data from the different tools. The most used data standard for this purpose is IFC (Industry Foundation Classes). This data standard is developed and maintained by BuildingSMART International. It contains around 800 objects and properties. All of which have a semantic documentation. This is very important for the interoperability of data in the industry. Every software tool that calls itself a BIM tool has an IFC import/export function. In the IFC ecosystem other data standards are also interesting: mvdxml to define Model View Definitions that filter a part of IFC for specific applications; ifcxml (same as IFC, but different syntax) simple ifcxml (same as ifcxml, but less overhead in the syntax) COBie (well known MVD specifically for Facility Management) BIM Collaboration Format (BCF) for issue management Other non-buildingsmart BIM data standards are BIMxml, gbxml and STL. All of these have little traction compared to IFC. Besides BIM data standards other standards arise for the use of BIM. For example, the open query language BimQL is the de facto standard for queries on IFC. 2.3 BIMSERVER BIM adaptation is not on the level yet where online interaction is considered to be a necessity. The next step in BIM is the shift from file based data to online databases. Many online BIM platforms are being developed at the moment. All of them have specific features and both positive and negative points. In ELASSTIC we used the open source BIMserver.org platform to get BIM objects online. This initiative started in 2008 when the industry was still unaware of the concept of online BIM. The stability of the BIMserver.org platform is proven enterprise ready. Many commercial applications build on the stable base of BIMserver. The principle of the ELASSTIC BIM concept is to automate simulations based on BIM data. The API of BIMserver is based on the open API standard BIMSie (Building Information Service Interface exchange). This open standard from Buildingsmart Alliance makes it possible for online BIM platforms to automate interaction between each other. In the ELASSTIC project an instance of BIMserver is hosted on ELASSTICbim.eu. This server had a 56Gb RAM, 4 CPU setup. During the project the server was upgraded to a 128Gb RAM machine. The ELASSTIC BIMserver started with version 1.2. During the project it was updated to 1.3. A number of plugins was used to facilitate specific features. During the whole ELASSTIC project the bimvie.ws GUI plugin was used as a Graphical User interface to let users interact with the ELASSTIC BIMserver. IfcOpenShell was used as the default render engine to render geometry and perform Boolean operations on the model. FINAL 10

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12 3 BIM data in ELASSTIC For the ELASSTIC project the building models for the disciplines Architecture, Structural and MEP are created individually for each discipline. All models are created using Revit (version 2014 and 2015). In order to ensure that all disciplines always work with the latest information, all models are saved in Buzzsaw environment. These models are automatically updated daily, and it is also automatically exported daily to IFC format. Besides to the modelling platform project partner Arcadis used softwaretool Relatics to manage a requirements database and insert extra information when needed into the Revit models. Also relevant data from the Revit model are inserted into the Relatics database so that analysis can be made. The connection of the data exchange works two ways: from Revit to Relatics, and from Relatics to Revit. The resulting IFC data is send to the BIM Gateway (BIMserver) for further analyses. The setup is shown in the next picture: Figure 1: data connections in ELASSTIC (source: Arcadis) 3.1 ANALYSES OF BIM DATA The building model in ELASSTIC was split into 5 different sections. More on that in the chapter performance. The 5 sections together formed the whole building. Within the 5 sections discipline models were created for the disciplines Architecture, Construction and MEP. The project structure on the ELASSTIC BIMserver looked like this: FINAL 12

13 Figure 2: project structure on ELASSTICbim.eu In total 32 revisions were checked into the ELASSTIC BIM server during the creation of the first design. In the final revision of the first design, the total number of BIM objects that was created was almost 20 million ( ). To give a small indication of the type of objects: 1151 beams were modelled; 1222 columns; 2041 doors; 764 slabs; 1170 spaces; 332 stairs; 2526 windows This resulted in: cartisian points; IFC faces; The most used IFC object IfcPolyLoop: occurrences. The IfcClassification object is only used 15 times. An overview of the classes: FINAL 13

14 Figure 3:overview of the used classes (number of instances) The reason why there are 13 building objects in this revision in database is the use of discipline models and the sectioning of the building. When the sub-models are merged ( fusion ) the merge algorithm is able to create a model with only one building object. The merge feature of BIMserver is performed by a plugin. By default there are 3 plugins provided: Merging based on GUID of objects; Merging based on IfcName string; Basic merging. When using the GUID based merging, the algorithm tries to find objects with the same Global Unique Identifier (GUID) in different models in a project. When these objects are found, the algorithm merges them into one object. The principle is the same in the algorithm that merged based on IfcName strings, with the obvious difference this looks for identical strings of the IfcName objects instead of GUIDs. FINAL 14

15 The basic merging algorithm just collects all the objects and places them in a resulting model. In ELASSTIC, due to evaluation reasons, this algorithm was used most of the time. All merging algorithms can t guarantee to result in a valid IFC model. This is due to the nature of the data schema IFC. In a visualization on the ELASSTIC BIMserver it looks like this: Figure 4: visualisation of the ELASSTIC BIM using the bimvie.ws GUI plugin of BIMserver The geometry is quite detailed. The metrics about the geometric triangles calculated by the IfcOpenShell plugin: Model Nr Primitives Nr Triangles Ribbon 0 Architecture Ribbon 0 - Construction Ribbon 0 - MEP Ribbon 1 - Architecture Ribbon 1 - Construction Ribbon 1 - MEP Ribbon 2 - Architecture Ribbon 2 - Construction Ribbon 2 - MEP Ribbon 3 - Architecture Ribbon 3 - Construction Ribbon 3 - MEP Ribbon 4 - Architecture FINAL 15

16 Ribbon 4 - Construction Ribbon 4 - MEP Total: This shows that the construction models are by far the most detailed in geometry. FINAL 16

17 4 ELASSTIC technology concept An overview of the technology in the ELASSTIC project. 4.1 THE ELASSTIC BIM CONCEPT: INTEGRATION OF TECHNOLOGIES The ELASSTIC BIM concept consists of three main clusters of technology: - Building Information - Simulation models - Sensor information The ELASSTIC concept is about the communication between these three main technology groups. The rest of this report will focus on the automation of the communication between these datasets. The dataflow will be described in chapter 5; The BIM data in chapter 6 and the Simulation models in chapter 7. A fourth technology called Multi Criteria Analyses (MCA) is providing the end-user the interface to evaluate safety and security of the building design. The link to the MCA tool is elaborated in chapter 9. Figure 5: The relation between the technology groups in ELASSTIC The concept is best described with an example. Let s focus on the case of a fire in a building. In case of a fire in a building, the sensors from the Building Management System (BMS) pick it up. The BMS probably responds with the classic sprinkler system. A notification of the fire is also send to the evacuation simulation. The location of the fire, and maybe intensity are available data at this moment in the FINAL 17

18 process. With advances in building management systems the number of people and their location might also be available as data. The evacuation simulation calculates the most effective evacuation route for the people in the building. To do this, it needs to calculate the spread of the fire so it also triggers the fire simulation. For these simulations information about the building is needed. This data comes from the (static) BIM. When the BIM data shows installations with high risk of explosions, the explosion simulation can be triggered. The structural integrity of the building might also be evaluated due to the effects of the fire and/or explosions. The most effective evacuation route is send to the building management system. By using signs the people in the building can be evacuated via the safest route in the most effective and efficient way. When people don t use the suggested route, sensors (like cameras) can pick up this deviation and start a new simulation. Resulting in a recalculated optimum evacuation route that is send to the building management system. Other information from sensors can also influence the process flow. For example when walls break down due to fire; the BIM data set gets updated and this new dataset is used as the base for evacuation simulation. In this case new evacuation routes may come available. Or when parts of the building won t provide structural safety anymore (found by a combination of sensors in load bearing columns and beams) this part might be prioritized in the evacuation (and the BIM data updated). This is what we mean with the term ELASSTIC BIM Concept. 4.2 IT ARCHITECTURE The basic principle of this concept is that the sensors, the BIM data and the simulations are not lined up in a predefined workflow. The interaction between these tools is event driven. Figure 6: principle of event-driven architecture (source: Microsoft) The principle of even driven interaction is not new in IT architecture but never applied in this way on a building. It facilitates the use of small microservices that seamlessly connect and integrate. These small services "do one thing and do it well". It is described as follows: The services are small - fine-grained to perform a single function. FINAL 18

19 The organization culture should embrace automation of tasks. The culture and design principles should embrace failure and faults, similar to anti-fragile systems. Each service is elastic, resilient, composable, minimal, and complete. Figure 7: Linking 'microservices' in an event driven ecosystem (source: PWC) The concept of micro-services is used in ELASSTIC to connect the different simulation tools to the BIM data. Every simulation tool should be developed as an online service that is minimal and complete. The interface to the tools should be BIM compatible. This brings a challenge for the individual simulation tools, but is the most durable architecture for long term innovations and business models LINKING TO BUILDING MANAGEMENT SYSTEM AND SENSOR INFORMATION The BIM concept described in this report has a strong focus on the connection between the BIM information in the static BIM database and the simulation models. The connection between the simulation tools and the information from the building management system and sensors is not described in detail in this report. During the project some experiments where done to connect sensor information to static BIM data. The IFC object IfcSensor was used to model the location of the sensors in the building. The obix standard was used to exchange information between sensors and BIM. obix (Open Building Information Xchange) is a focused effort by industry leaders and associations working toward creating a standard XML and Web Services guideline to facilitate the exchange of information between intelligent buildings, enable enterprise application integration and bring forth true systems integration. Based on Standards widely used by the IT Industry, the obix guideline will improve operational effectiveness giving facility managers and building owners increased knowledge and control of their properties. Comprised of representatives from the entire spectrum of the buildings systems industry, obix includes professionals from the security, HVAC, building automation, open protocol and IT disciplines. (Bogen, 2014) The software implementation used to synchronize sensor information and static BIM data was the Enterprise Service Bus (ESB) from WSO2. WSO2 Enterprise Service Bus is a lightweight, high performance, and comprehensive ESB. 100% open source, the WSO2 ESB effectively addresses integration standards and supports all integration patterns, enabling interoperability among various heterogeneous systems and business applications. (source: WSO2 website) FINAL 19

20 The experiment proved the technical feasibility between BIM data and more dynamic data from sensors and building management systems. 4.3 DESIGN EVALUATION In the ELASSTIC project an extra element is added: the Multi Criteria Analysis. The focus of the ELASSTIC project is to make the simulation models available during the design of a building. In this way the design can be optimized for safe and secure buildings. When multiple simulations are available on the BIM data of the design they need to be compared against each other. Some design decisions may have a positive effect on the evacuation simulation, but a negative effect on the fire safety. The MCA technology creates an interface on the overall view of the different simulations of the design. Figure 8: MCA impression The ELASSTIC BIM work package has a strong focus on improving the design. Therefore there is little connection to the sensors and building management system and extra focus on the connection to the MCA tools. 4.4 INNOVATION The core innovation of the ELASSTIC BIM concept is the automation of human tasks. By automating operations on BIM data the manual workload is eliminated. At this moment the industry is driven by a process that has little information in the beginning of a project, and high influence on the changes. Later in the process the ability to influence costs is limited. In this stage however, there is much more information. FINAL 20

21 Figure 9: the relation between project costs and level of influence (source: many) The ideal is to have valuable information earlier in the process, when there is still the ability to influence the project. BIM is often seen as a technology that could be used to increase the information in the early project process. In this way better information is available earlier to make better informed decisions at a moment where there is still a significant ability to influence the project. However, research has indicated that using BIM could shift the workload to an earlier phase of the project without always having the benefits of influencing the project. Many project participants are only involved after a certain point in the process. These partners (for example suppliers) don t have an interest in delivering information earlier in a project without guarantee of a stable process. This situation creates a lock-in. Certain project partners cannot invest in providing information earlier in the process because the risk of changes in the project is too high. Evolving these partners as advisers means they have to be paid for their advice, independent from their role in the project. A solution could be to deliver an advise to the project based on knowledge rules. An automated expert system could analyze the project data and send back an automated result. This eliminates the costs of human involvement. By having bots (automated expert systems) analyzing the data every time there is a (significant) change of the design, the provided results could actually steer the design team. When the information from the bots is provided within minutes, the design team can use the provided information to change and experiment with the design. In the current process, energy analyses are only done at the last minute before a permit is needed. By using automated bots to perform a (high level; indicative) energy analysis every time the design changes, the designer can use this to optimize the design. Other performance analyses like CO2 analyses, fire safety simulations or logistic optimizations are barely conducted in a project these days (even in BIM projects). By providing an automated bot for this the costs to perform such a simulation can be very low. FINAL 21

22 This lowers the threshold to use these simulations earlier in the project, and even opens opportunities for expert opinions that could never be given so early in the project. In the ELASSTIC project we have tried to automate several simulations. In the next chapter we will focus on how they were connected to this concept. FINAL 22

23 5 ELASSTIC data flow This section describes the flow of data between the different data hubs and simulation models in ELASSTIC. 5.1 SIMULATION MODELS Within the ELASSTIC EU project several simulation models use BIM data for their simulations. An overview: Evacuation simulation (pedestrian stream); Explosion simulation; Structural integrity after earthquake; Structural analyses Fire spread simulation Energy simulation Before the start of the project these simulation tools had little or no input option for BIM data. The simulations had their own (proprietary) input interface. The biggest challenge was to create a connector to read BIM data to feed the simulations. For reasons of consistency and durability the open BIM data standard IFC was chosen as the interface to BIM data. The simulation tools needed to create an interface to read data structured according to the IFC data schema (more on this in another chapter). 5.2 DOMAIN SPECIFIC REQUIREMENTS Different simulation models need different structured IFC input data. For example the simulation of the evacuation has a strong focus on getting data about staircases, hallways and spaces. For this simulation there needs to be a semantic difference between different spaces like an office, a hotel room, a hallway and an installation shaft. The structural integrity simulation does not have any focus on spaces, but needs information about materialisation, stability principles, etc. To use the information in the simulations, it needs to be in IFC, and therefore someone needs to model it in the BIM modelling tool. During the ELASSTIC project the development of the simulation requirements and the modelling of the BIM was done in parallel. Therefore the requirements of the input data for the simulation models was not always available for the BIM modellers during the modelling. This resulted in a situation where not all data was available for the simulation models at the time they needed to provide results. 5.3 CLASSIFICATIONS To further enrich IFC data with additional semantics, so called classifications can be used. In IFC a space is modelled as an IfcSpace object. This can be any kind of space. To detail the semantics of a space it can be classified as an office or hallway. This classifying can be done with terms that the BIM modeller FINAL 23

24 just makes up, or a project team agrees to use one specific. For efficiency reasons standardized classification references are used. Commons classifications are the omniclass (US), uniclass (UK) and in the Netherlands NlSfb. There are many efforts to map the different classification systems (like CB-NL in the Netherlands), or to make one overall classification system that replaces all others (like BSDD Buildingsmart Data Dictionary ). These initiatives have not proven to be stable nor effective yet and are therefore not used during the ELASSTIC project. In a workshop in Rotterdam in July 2014 it was agreed to use the omniclass classification system. Main reason for this choice was that most of the objects in the IFC repository at that time already had omniclass references. This was due to the fact that most used BIM modelling tool Revit uses this by default. The omniclass reference provides rich semantics to facilitate the different needs of the simulation tools in ELASSTIC. The project team also agreed to only use English language and terms from EN publication. Correctly classifying BIM objects according to the omniclass system has proven to be an effective solution to enrich BIM objects. However, in the ELASSTIC project not all BIM data (and IFC extracts of that) where classified with omniclass. Many different classifications where found in the data, some even in different languages than English. This resulted in IFC data that was not usable for some simulation tools. 5.4 MODEL VIEW DEFINITIONS (MVD) The IFC data schema is very extensive and rich. It has about 800 objects and properties defined. FINAL 24

25 Figure 10: IFC definition and properties of a "Door" This picture is unclear. It is not intended to be read in detail; the purpose of this picture is to show how much is standardized in IFC for just a door. FINAL 25

26 The full extent of the IFC agreements are never implemented in software tools. Software vendors only support a part of the full IFC agreement. To define what parts the concept of Model View Definitions (MVDs) is created. An MVD defines which parts of the full IFC agreement are supported. The most used and infamous MVD is the coordination view. Almost every IFC export from a major BIM software tool exports IFC according to the Coordination View MVD. The services that run operations on data in the ELASSTIC concept also have specific requirements. We will go into that in a later chapter but to give an example: the explosion model needs to know which walls are loadbearing; need specific (detailed) properties of the glass and can only handle tessellated geometry (without Boolean operations). This is a kind of MVD, although it is not officially registered as a BuildingSMART MVD (note: BuildingSMART is the owner and developer of IFC and the official MVDs). To define a specific MVD a new standard is in the making: mvdxml. This is an XML syntax to define a specific MVD for your own software tool. Datasets can then be checked against the mvdxml file to validate if all the data is available for the software tool to perform. During the ELASSTIC project the mvdxml development was followed with high interest. Both theoretical desk research, as practical implementations have indicated that the current mvdxml development cannot be used to define MVDs for the tools used in ELASSTIC. This is due to limitations of the chosen mvdxml technology. The development team of mvdxml indicated that the request from the ELASSTIC project won t be on the priority list until several other releases of mvdxml. During the ELASSTIC project a new version of BimQL has been developed to solve these issues. Using a query language to replace the concept of MVDs showed to be a valid approach. This new version (wich is JSON based) is proposed to the BimQL development team and is now under consideration. At the end of the ELASSTIC project the project partners found that the MVD concept and/or query language should also be capable of performing rudimentary geometric operations. During the ELASSTIC project we experimented with this and this was brought to BimQL as an addendum to the original consideration. 5.5 SUPPORTING TOOLS It was decided to use a BIMserver.org platform instance as the gateway to the (automated) simulation tools. The BIMserver.org platform has several features that can be used to support the simulation tools to get the most efficient data. Also the BIM modeler can be provided with feedback on the quality of the BIM data BIMSERVER.ORG BIMserver.org is an open source initiative to provide the industry with a stable base to store and work with IFC data. The core of BIMserver uses an Oracle (BerkeleyDB) key-value store database. On top of that several service layers are used to perform intelligent operations on the data. BIMserver.org does not have an end-user oriented Graphical User Interface (GUI) and is not intended to be an end-user focused tool. Basically BIMserver.org is an intelligent IFC database meant for developers to build their tools on. Multiple end-user products use the BIMserver.org platform as a base and the BIMserver initiative has proven many times to be enterprise stable. Almost every feature in BIMserver is provided in a plugin infrastructure. The import (deserialization), export (serialization), querying, geometry rendering, model checking and internal service operators are all plugins that can be replaced and tweaked. FINAL 26

27 In the ELASSTIC project a BIMserver instance was used with these plugins: IfcOpenShell: as the IFC render engine to perform Boolean operations, color & transparency calculation and tessellation of the geometry. The plugin is triggered with every deserialization of IFC. It generates the triangles and stores the results in the BIMserver database. bimvie.ws: as the Graphical User Interface to perform end-user oriented operations on the BIMserver instance (upload, download, view, etc.). This is the only known open source GUI plugin for BIMserver. Although it was far from stable we used it in the project. This plugin didn t perform as the users expected. BimQL: as one of the main query engines. The standard IFC plugins of BIMserver to perform import (deserialization) and export (serialization) of IFC data. For ELASSTIC several custom plugins for model checking and internal data transformation where used. More on that in the next paragraphs MODEL CHECKING The Model checking feature of BIMserver gives users the ability to write their own check to be performed on the IFC data. This is done by writing Java code. The plugin framework is extendable to create mvdxml model check plugins or any other kinds. Every model check is a separate plugin. A check can be done on two points in the data flow process: At check-in; before the data are stored in the database as a new revision After checking; before a trigger is send out to a (internal or remote) service In ELASSTIC model checks were not used that intense. The structural analyses service ( bot ) wanted to make sure that structural elements of a new revision where changed. Otherwise the analyses service doesn t want to receive a trigger (note: the structural analyses took a very long time to run). For this situation we developed a custom made model check plugin that checked if any structural element was changed compared to the previous revision in the database. In a future setup of the ELASSTIC BIM concept, model checks can be used to guarantee if a dataset has enough and high quality data to perform a simulation or analyses DATA TRANSFORMATION SERVICES Another plugin capability of BIMserver is to write a so called internal service. This can be done in JAVA. Basically an internal service can perform any kind of operation on IFC data. This can be used (and misused) for many purposes. The internal services work the same as remote services (see next chapter): they perform an operation on the data and send back a result. This can be a new revision of IFC, or extended data (or both). FINAL 27

28 In ELASSTIC the internal services were used to perform simple operations on the data to make it easier for the remote services ( bots ) to use the data. For example an internal service as made that places random furniture in all rooms ( IfcSpace ) of the model. This would deliver more reliable input data for the evacuation simulation. Placing furniture in the model by hand would be a huge, time consuming task. Placing it with an internal service automated this task and got a result in seconds. Another internal service developed for ELASSTIC gathered surface area information from several objects and stored them at a convenient location in IFC. This was done on the request of several remote services (and MCA) to get easier access to the information. More common use of the internal service plugin feature is to transform data into a different representation. For example complex, detailed geometry can be transformed to less detail so analysis tools can perform faster. A popular internal service checks if all Unique ID s of the model are indeed unique. If not, it will change the ID s into unique ones and deliver a new, corrected, revision as a result. This is done within seconds. In general terms these services pre- or post-process the data to optimise the transfer to other tools. This pragmatic solution approach showed to bring great potential to the use of IFC in an enterprise environment. FINAL 28

29 6 ELASSTIC BIM gateway The workflow between BIMserver and the simulation models is event driven. Every simulation model can subscribe to events on the used BIMserver in which they have interest. When this event occurs the BIMserver sends a notification of the event to the subscribed simulation service(s). The simulation service(s) most probably run on a separate (remote) server. This server can then perform actions on (using a token as login) and send the results back to the BIMserver, or to any other service. This way a chain of event driven services can be triggered on an event (like new revision ). The next paragraphs will describe the setup process and technology involved in more detail. Because the ELASSTIC project will probably use the trigger new revision the next paragraphs will focus on that example. 6.1 PROCESS INSIDE BIMSERVER Inside BIMserver.org the process from checking in a new revision to possibly sending out a new notification undergoes multiple stages. FINAL 29

30 OK Services subscribed OK Message send to user D2.5 REPORT ON IMPROVED USAGE OF BIM TECHNOLOGY User check-in of new data Modelcheck by server (1) Not OK? Check-in refused New revision is created No services subscribed? Modelcheck by server (2) Not OK? Notification is send to subscribed service Figure 11: The process inside BIMserver when new data is checked in The process is usually started with an action ( event ). In this example the action comes from a user, but it might as well come from another service or any other automated process. 6.2 SETTING UP A NOTIFICATION/TRIGGER Setting up a trigger only has to be done once and can be done by any user or administrator of the project. Once the remote service (as it is called in BIMserver.org) is setup, notifications are send every time the event takes place. No other configuration is required. FINAL 30

31 The steps that are needed to setup a trigger and send out a remote service are the following: User chooses add service to project of choice BIMserver gets a list of known services from a repository server User chooses a service from the list BIMserver gets information about that service, including public profiles User provides token of remote service user to choose private profile User chooses known public profile User configures access rights (links access rights to send out token) BIMserver administrator adds allowed data schema BIMserver gets modelchecking snippets from online repository User chooses (one or more) modelchecking snippets BIMserver sets the trigger as configured Figure 12: process to setup a trigger in a BIMserver FINAL 31

32 Figure 13: the list of available services ('bots') 6.3 PROCESS OUTSIDE BIMSERVER When a BIMserver sends out a notification to a subscribed service, the process basically stops. The remote service does not have to provide a response. 6.4 EXTERNAL SERVICE ( BOT ) RUNNING The external service receives the notification. The notification isn t more than a token to obtain the data from the revision. The token gives limited access rights to the data. The external service can query the data. The whole revision can be transferred from the gateway (BIMserver) to the external service, but the service is also able to query the data in the gateway (BIMserver) to only get the data it requires QUERY LANGUAGE At the start of the project the BimQL open BIM Query Language was used to perform queries on the data. During the project more advanced queries where requested by some simulation models. Therefore the ELASSTIC project participated in developing a new IFC filter language based on JSON syntax. Experiments with this new filter language were performed only at the end of the ELASSTIC project, but seemed very promising. 6.5 REMOTE DATA COMING BACK When a trigger is send out to a remote service, the only thing that is send is a token. When a remote service connects to BIMserver with this token, BIMserver checks what access rights the token gives. It does not check if the token is being used by the same remote server as it has been send to (for flexibility reasons). When IFC is checked in with this token, a new revision is made to the associated project. When extended data comes in BIMserver should check if the data is structured according to an allowed schema of the server. At this moment this feature is not implemented yet. This feature should give the server administrator the ability to manage what data comes into the server. FINAL 32

33 When remote services are performing simulations on the data that take a long time to run, the resulting data is not instant. To avoid the situation where users will trigger the remote service again, the services can send progress information to the BIM Gateway (BIMserver). This is done by sending progress updates to the BIM gateway (BIMserver). The BIMSie API standard module progress information was used to support this. 6.6 LOG OF ELASSTIC WORKFLOW The BIMserver was not used as a collaboration tool during the first design. The focus of the ELASSTIC project was about automating the simulations based on BIM data in the BIMserver database. The BIMserver instance (ELASSTICbim.eu) was used as a gateway to put the models online and trigger the (remote) simulation services. The log file of the ELASSTICbim.eu BIMserver instance was analysed. This resulted in the following event log schema: Figure 14: Event log analyses of the ELASSTICBIM.eu log A better readable version of this schema can be found in appendix 2. The analyses of the event log of BIMserver show that many of the BIMserver features were used during the ELASSTIC project. 6.7 THE ELASSTIC SETUP In the ELASSTIC project several services were used to perform operations. The setup is shown in the next image: FINAL 33

34 Figure 15: the ELASSTIC BIM ecosystem At the core of the workflow a BIMserver.org instance is used (with the bimvie.ws GUI plugin). When data complies to certain model checks, triggers are send out to a clash detection service; a furniture placer; a validation checker; a simplifier; and the explosion simulation. These services can then trigger the evacuation simulation; a (very simple) fire simulation and a COBie exporter. In the end several services can update the viewer. The MCA link is not shown in this picture. During the ELASSTIC project we found that there can be several returning loops in this setup. By using correct model checks these loops will not be triggering each other into an endless loop. As you can see in the image, several support -bots were used to adapt the BIM data and make it available for the simulation models. The simplifier service, the validation checker and the furniture placer are all examples of implementations that perform automated actions on data to make it suitable for the simulation models. FINAL 34

35 Figure 16: result of the 'simplifier' BIM Bots remote service Figure 17: the simplified model and the original Ribbon 1 model in the same view on BIMserver with bimvie.ws FINAL 35

36 Figure 18: the simplified model and the original Ribbon 1 model in the same view on BIMserver with bimvie.ws FINAL 36

37 7 The ELASSTIC Simulation models The simulation models used in ELASSTIC are: - Explosion simulation: simulating damage after detonation of an explosive inside or outside near the building. Results can be chance of survival per room; broken windows; etc.. The expertise from TNO was used in this simulation. - Pedestrian stream / Evacuation simulation: simulating the stream of people leaving the building. Result of the simulation can be the time that the whole building is evacuated; locations in the building that obstruct a smooth evacuation; etc. The expertise of Siemens was used for this simulation. - Earthquake simulation: this simulation calculated the structural integrity of the building after an earthquake. Result is a Boolean if the building still stands or not. The expertise of Schüßler-Plan is used for this. - Structural simulations: this simulation calculates the deformations and stresses. The results are used for analyses of impacts from strong winds due to climate changes. The expertise of Arcadis is used for this. - Energy simulations: simulation of the energy use of the building. The expertise of Arcadis is used for this. 7.1 TRIGGERING THE SIMULATION MODELS During the ELASSTIC project the focus was on running simulations on the IFC (BIM) data. Therefore most of the simulation models weren t capable of running in an online (cloud) environment. The triggering of the simulation models therefore went to a void. Some simulation models avoid this by polling for a new revision om the BIM gateway (BIMserver) every minute (or other timeframe). This obviously brought a high load of traffic and makes the BIM gateway vulnerable for traffic overload. The supporting services (furniture places, validation checker, simplifier) did use the trigger function and proved the workability of the concept. In general terms these services pre-process the data to optimise the transfer to the simulation tools. The general consensus in the project is that running the simulation models online is a lot of work, but not a technical challenge. Therefore the priority of actually accomplishing this was relatively low. 7.2 EXPLOSION SIMULATION (TNO) The façade-model in the SPIRIT-tool [Boonacker, 2014] is used for the façade analysis. Within the FP7 framework project SPIRIT (EU funded) this quick method for façade analysis has been developed. This method was developed for a first order estimate of potential blast damage to building façades and provides a quick insight in the resistance of a building and its façade at an early design stage. This model is described in paragraph in deliverable D2.4. In the ELASSTIC project it is agreed that the BIMserver is the portal to the simulation models. FINAL 37

38 To use the façade-model for the ELASSTIC building, a connection must be made between the IFC model of the building and the façade-model. Because of the differences between the building definitions in the SPIRIT tool and in the IFC model, the hazards models of the SPIRIT tool are put into a dynamic-link library (dll). The challenge was then to connect the SPIRIT.dll with the IFC model. Different steps had to be added or changed to make an automated process between the façade model and the IFC model of the ELASSTIC building. The process and the different steps are illustrated in the figure below. BIM server IFC model of building Explosion scenario parameters are not (yet) in the BIM server Wrapper unpack database recognition different objects Converter determine which object are inside or outside facade parts determined normal vector of the facade to the outside determine adjacent facades and their corners SPIRIT.dll + Features changed for connection with IFC model: Determination if the requested facade objects have direct or indirect sight to the explosion For object with indirect sight to the explosion the shortest route around the building is calculated User interface The SPIRIT model results: yes/no failure of the selected object (% failure can also be an option) Simple interface to communicate with the SPIRIT.dll to change: object names to be considered the explosion scenario (charge weight and location) the resistance level of the objects Output JSON: requested to be used with the BIM server for graphic output Excel: Data output Sketchup: fast and simple graphical output For every step different new features and some difficulties are encountered with the IFC model. The steps taken, lessons learned and solutions made are given below IFC MODEL OF THE BUILDING The ELASSTIC building is a very large building complex. The building is therefore divided into several parts indicated as ribbons. It is difficult to download the whole complex, because the ribbons all have their own IFC model. FINAL 38

39 At the start of the project problems were encountered to gain access to the BIMserver, like account not valid or blocked. For the calculations the IFC model was not used within the BIMserver. The IFC model was downloaded from the BIMserver to be used for the models RECOGNITION OF DIFFERENT OBJECTS AND ITS CHARACTERISTICS For the SPIRIT model the building material of the façade is a necessary input parameter. So for the façade objects the material must be clear. In the IFC model objects are defined as a type (for example window or wall) and are given a name. The type and name are not standardized and for recognition of the different objects, it is recommended to first view the building how the different objects are defined. For the damage to the façade the first focus was on the glazing part of the façade. For the ELASSTIC building two window types are defined, but only one consists of glass: - Window type CAD-fenêtreUtilisateur called 'Fenetre 1x3'. This is an adjustable window style with a default dimension but in the model is drawn as 870 x 2000mm. It is the transparent windows in the 'solid' facades of the Ribbon buildings. - Window type Fenetre-ouverture carrée-filled called 0870 x This is an opening to the façade (similar to Fenetre 1x3) but is filled in with a solid sandwich cladding therefore there is no glazing. Another façade object made of glass is a wall type mur de base called 'CAD-vitree5'. It is to represent the curtain walling for the transparent facades of the Ribbon buildings. The wall type in the IFC model is 200mm thick, but the glazing element is represented as being 50mm thick with 150mm thick air space. This is at scheme design level. Also the size is still at scheme level. The walls are much wider than the individual glass panels will be. Details of the glass thickness or quality are not (yet) given in the IFC model. This is not a problem. This information can to be added directly in the software or in the user interface as input for the SPIRIT.dll. For this different assumptions have to be made. It can be concluded that the type and name of an object cannot be straightforwardly or directly linked to the building material. To improve the connection between the façade model it is recommended that the type and names are more straightforward and can be easily recognized as a specific building material. It would be a great improvement if these input parameters are standardized if possible DETERMINATION OF THE FAÇADE: In the BIMserver the function InternalOrExternalBoundary is available to quickly scan the model for the envelope of the building. For the ELASSTIC IFC model this function could not be used, because some spaces which are totally inside have walls or windows that are in the boundary-bin. This means that some inside walls and windows have the indication EXTERNAL. This will lead to errors in the façade definition. To determine the envelope of the building and the normal of the planes to the outside a new procedure is made: To determine the façade planes the following method is used. From all known objects in the BIM database, a line is drawn from their middle point running parallel to their normal. Each object that is hit by this line will be collected and from this skewer the first and last object could be an object in the façade. So after each stitch two objects are found and their middle point and normal is representing two façade planes in FINAL 39

40 the building complex. Then a distinction is made between similar planes and these are the planes of the building. To determine the normal vector of the objects to the outside another procedure is used. The centre of adjacent objects is clustered with the Gonzales algorithm (Density based Clustering (DBSAN)). This gives a centroid for part of a building. For the façade objects the normal vector to the outside is pointed away from its nearest centroid. This method works very well when the object density is high. For building parts with a very low object density inside, it can give some difficulties. For the ELASSTIC building this is only the case for the one museum space, were no internal walls or rooms are located. The Gonzales algorithm is also used to cluster the façade objects which have been found in the façade planes to determine the façade face. When these faces are defined, the intersection lines and cornerpoints of the adjacent façade face in the building can be found. Determination if the requested facade objects have direct or indirect sight to the explosion The poking algorithm as is used to determine the façade objects, is also used to determine if a façade object has a direct or indirect sight to the explosion. From the explosion location direct lines are made to the façade objects. If these lines do not cross façade face, the specific façade object has a direct line of sight. If not it has an indirect line of sight. When a façade object has a direct line of sight, the perpendicular distance to the façade of that object (R) and the distance along the façade to that object (S) is determined. With this input and the resistance level of the object, the SPIRIT.dll calculates if the object would fail or not. For these calculations the center of the façade object is taken. It is also possible to calculate the average chance on failure by taking five locations of the façade object (all corners and the center). This means that for each object five calculations have to be done and thus that the calculation time increases and the output file increases. For façade object with indirect sight to the explosion the shortest route around the building is calculated When a façade object has an indirect line of sight, the shortest distance from the explosion to the object must be determined. For this a new procedure has been made. The façade is unfolded as indicated in the figure below, which makes the determination of the distances much easier. Figure 19: For façade object with indirect sight to the explosion the shortest route around the building is calculated In the current model this procedure works for rectangular shaped building contours. It can be easily expanded for polygonal shaped buildings. It does not work correctly when the building contour has recesses or cavities. For those contours the path along the recess or cavity is taken along the building contours, which is longer than the shortest distance. FINAL 40

41 1.1.4 RESULTS AND VISUALISATION The simulation of the explosion model returns a result in a JSON format with broken windows. More on this in chapter 8.3: Visualisation of results. The JSON structured data was placed on the BIMserver gateway in the extended data part alongside the revision of the IFC data. When the user visualized the original IFC data in bimviews, the bimviews plugin of BIMserver recognised the extended data JSON file and added an extra visualisation option for the explosion results. An impression of this can be found in the following pictures. Figure 20: impression of the visualisation of results (broken windows) as an overlay over the original IFC data Figure 21: impression of the visualisation of results (broken windows) as an overlay over the original IFC data FINAL 41

42 Figure 22: impression of the additional feature in the bimvie.ws visualisation when a JSON result is placed as 'extended data' 7.3 PEDESTRIAN STREAM (SIEMENS) In the ELASSTIC project Siemens integrated the provided BIM-IFC models with a pedestrian stream simulation in order to calculate evacuation times in an early stage of building design. This has to become an iterative process: i.e. the architect creates a design for the building, which is afterwards completed by the MEP structure of civil engineering. Before the models are detailed in another iteration of the design process, the concept is checked for conformance with mandatory building codes, (in our case) particularly regarding the evacuation time of the building complex. This will then lead to different recommendations (like wider exit doors), which again triggers another iteration. In order to set up a simulation environment for evacuation calculation, relevant parts of the building are imported from the available IFC files. At this stage, the source of information (from server or from file) is not so relevant, since access to data is read-only and no real-time requirements apply to the process. Therefore, Siemens performed the experiments based on IFC files, which were extracted from the BIM server manually or which were directly provided by the architects / civil engineers. The layout of the first version of IFC data already exposed several issues. BIM-IFC leaves a lot of freedom for designers to define the same elements in different ways. While this is definitely a good feature for designers, it drastically increases the number of combinations and special cases for data analysts later in the pipeline. Three topics in the design layout therefore had to be addressed before an import of the building data was possible: Usually all elements in both IFC data and simulation data are assigned to a dedicated floor of the building. However, in IFC it is allowed to have elements, which are not assigned to a floor or which are valid across several floors. For the Ribbon building of the ELASSTIC project, the first version contained a façade across all floors, but this element also serves as boundary for the individual levels. This cannot be detected automatically by the import routines of the simulator. Therefore the easiest solution was to ask the architects for a redesign, e.g. splitting the façade into several pieces, which can be assigned to a certain floor of the building. Regarding stair cases, the BuildingSMART definition of IFC already provides a lot of design options. However, since stair cases are very individual parts of each building if they are seen as one component, most CAD programs do not disassemble staircases into the BuildingSMART primitives. By doing so, also some design elements like hand rails would be lost. Therefore, stair cases are simply exported as point clouds by most CAD programs (like REVIT). Although point clouds are valid IFC elements, they are hard to handle and interpret. The result was huge IFC files, which are hard to transfer. In addition, it was not possible to extract the relevant data (tread geometry, starting line, etc.) from the point cloud. Therefore, we asked the architects to include additional elements (like the entry and exit line of the stairs). These elements carry additional information in their parameters (like the tread geometry). However this solution is FINAL 42

43 specifically tailored for the pedestrian simulation and is not standardized. Apart from this information, the point cloud was simplified to reduce the file size. Another issue with the first version was the huge amount of data (apart from the point clouds). It turns out for the automated IFC export (e.g. in Revit) that it is not optimized for memory usage. Particularly it is not able to detect duplicates of elements (like the stair cases), but includes deep copies instead of references. Again, manual work was necessary to reduce the amount of exchanged data to a manageable amount. Proposed solution: in order to overcome the issues described above, it would be great to have a model, which provides different levels of detail, like it is the case for other 3D applications. Within the ELASSTIC context it would have been favourable to have at least three levels of details. The coarsest one provides just the external interfaces of the building, i.e. its size and look from outside and the main entrances. This information can be used for campus- or quarter-level simulations. Another level should contain information on which physically correct simulations of the building itself can be based (like pedestrian or energy simulations). A third level of detail could contain point clouds and non-functional elements to allow for a wide variety of designs. Regarding the import features of the simulator, Siemens also had to adjust this part on the simulation side in order to comply with different styles, which might be found in BIM IFC files: Different styles of joining walls (e.g. ArchiCAD vs. AutoCAD Revit) No definition in BIM how to define wall compartments Decorative BIM parts need to be removed (e.g. handrails) Different elements in 3D BIM have to be mapped onto the same 2D simulation elements (need to check for unwanted effects) Figure 23: These issues might occur due to ambiguities or missing definitions in the BIM standard One challenge for pedestrian simulations, as well as for fire and flooding simulations, is the mapping of 3D parts in BIM-IFC to 2D elements of the simulator. The first issue Siemens came across was the different FINAL 43

44 styles of connecting walls. As it can be observed in the picture on the top, different CAD programs export different styles. If the walls are now converted into lines without thickness, holes might result depending on the algorithm. This in turn will lead to errors in the underlying simulation. The same is true for decorative elements like hand rails, which are not aligned with the xy plane of the sketch. If they are just projected to the floor they are contained in, irrelevant obstacles will be produced. As mentioned above, BuildingSMART IFC defines different types of stair cases, while most simulators only provide one single type. Therefore a mapping has to be defined to match the parameters of the stairs with the parameters in the simulator. For example, spiral stair cases are mapped to ordinary ones, but the movement parameters of persons have to be adjusted to account for a slower movement on spiral stairs etc. While the calculations described above can be performed offline with static models, one goal of the ELASSTIC project was also to examine the coupling of online simulations to time-variant models. An example is the integration of the pedestrian simulation with a sensor network and a BIM server. One possible use case is the reaction of the pedestrian simulation to a change of the accessibility of building structures due to a fire. In a nutshell: the sensors detect a fire and trigger the calculation of the accessibility of the elements on the BIM server. Due to the changed accessibility, the BIM server wakes various observers like the pedestrian simulation to perform a situational intelligent response. In detail, the following steps are performed by the building management system (BMS) during that use case: firstly, the connection to the BIM server is initialized. As mentioned above the BIM server can reside at a remote location and the interaction will be performed via a web interface. The same applies to the sensor network, which is also represented by a web service, which has to be initialized prior to first usage. Afterwards, the BMS waits for the BIM server to be informed about any relevant changes an alternative to that would be active polling. If any structural changes on the BIM server are detected (e.g. limited accessibility of the corridor for user of the building), the BMS will recalculate the depending data, for example walk ways. In addition, all sensor readings are surveyed and checked against known thresholds (e.g. temperature or pressure). If a threshold is exceeded or structural changes are detected, the BMS starts the same procedure as before where will recalculate the depending data, for example walk ways. The model is converted to a format, Figure 24: process which can be understood by the simulator and the occupancy is added to the model. This can be either done by additional occupancy sensors or just provided by a static data base. Now the simulation can be used to calculate a new optimal route for occupants out of the building. As soon as the calculation has finished, the systems of the building will be updated (for example dynamic exit signs). So far for the theory in practice we observed some issues, which had to be solved before an online operation of the building can be demonstrated: FINAL 44

45 The connection from the Siemens campus to the official ELASSTIC BIM server in the Netherlands turned out to be slow and restrictions applied due to network security policies of both partners (Siemens and TNO). Therefore, a dedicated local copy of the BIM server was set-up for demonstration reasons. Even in the local version, getting selective data from the BIM server (like walls and slabs) was too slow for the complete building complex. This issue was solved by decomposing the data set into single building floors. Therefore, if a sensor on one floor was triggered, only this floor was fetched from the BIM server and the changes are merged into the simulator model. This worked quite well for the demo scenario, but might fail for scenarios, where multiple levels are afflicted. In that case the changes have to be processed in a sequential order, which might slow down calculations beyond real-time requirements. Another issue for that scenario was the missing definition of a generic sensor model in the BIM-IFC standard. Therefore dedicated elements for the sensors (like position in the building but also type and threshold of the sensor) have been added to the ELASSTIC models. However, this solution is specific for the demonstration and will not work in a wider context. 7.4 EARTHQUAKE (SCHÜßLER-PLAN) One of the tasks of Schüßler-Plan was the earthquake design of Ribbon 1. In order to perform this task, it was necessary to model the load bearing structure in 3D. The software which was chosen is InfoCAD. It is a commercial Finite-Element-Software, which has the option to import IFC-files. This option was tested during the ELASSTIC project but it was not successful and therefore not used during the project. The reason was that after importing the ifc-file the structural model had a lot of errors. One typical error was that plate elements (elements to model floor slabs) and beam elements (elements to model columns) had a gap between their nodes and did not meet at one point. Therefore, if the user wants to use this imported ifc-file for her/his structural analysis, she/he would have to do a lot of post processing in order to get a running structural model. This post processing is in general more time-consuming than the setup of a new model without an imported ifc-file. This second possibility was chosen for the ELASSTIC project. So, Schüßler-Plan modelled the whole structure again in InfoCAD and used the IFC-file just like a substitution for drawings. Schüßler-Plan confronted the company InfoGraph, which is the developer and the vendor of the InfoCAD software, with its findings. The company knew the problems but they were no willing to develop their software in this direction because the company thinks that this task is up to the developers of the IFC standard. 7.5 STRUCTURAL SIMULATIONS For the design of the structure, the building model is also used to simulate structural behaviour. The BIM models are often so complex that they are unnecessarily burdensome for the simulation and analysis software and demand a huge amount of computation time. For calculation purposes, only part of the building model is used STRUCTURAL DESIGN CALCULATION For the structural design calculations, analytical lines representing the load bearing of the construction, are needed. These analytical lines are available in the Revit model. Loads can also be added into this model. The interchangeability of the analytical lines between the software is still very limited, even though this FINAL 45

46 information is present in the IFC models. Here is an example of a structural wall element from the model of the Ribbon. Figure 25: Structural elements as part of the Ribbon Figure 26: Analytical lines for the structural calculations Since data exchange through IFC data wasn t a success for ARCADIS, they looked at an alternative. This is done by directly linking the BIM model and the analysis software. The ELASSTIC BIM concept was not maintained during this process. Nemetschek Scia has produced an add-in called SE Revit Link. This add-in can export directly from the BIM model to analytical data for the Scia engineer software. Loads can also be transferred. For buildings that are this complex, a certain amount of manual tweaking is needed in the end to get a number of elements to fit together properly. FINAL 46

47 Figure 27: Result of the exported model in SCIA Engineer WIND LOAD STRUCTURAL SIMULATION The BIM model of the Ribbon is also used for simulating the effect of the increased wind loads on the building resulting from climate change. Based on the assumption that the nominal wind load is going to occur more often, a greater wind load of approximately 15% is to be expected. The performance of the building based on this assumption is determined using the simulation. Figure 28: Concrete stresses as the result of increased wind load Figure 29: Flexing as a result of increased wind load FINAL 47

48 7.6 ENERGY SIMULATION In order to predict the energy efficiency of a building an energy simulation was performed. There are several commercial BIM-ready simulation software packages available. In this project ARCADIS evaluated three different products. Although there are examples known of projects where the import of the geometry was successful, ARCADIS were not able to import the geometry correctly. Two of the tested programs (Riuska and Vabi elements) uses an IFC import, DesignBuilder uses a gbxml format. Figure 30: IFC import Riuska The figure above shows the direct import of the IFC model into Riuska, most problems are related to the façade. Similar problems were found in the Vabi IFC import. Most problems where related to the low quality of the exported IFC data. In Revit a dedicated DesignBuilder export plug-in is available, using the native Revit-files (structural model linked to the architectural model) to generate an analytical model results in a better import. The concept of automating simulations in the ELASSTIC BIM Concept could not be maintained during this process. The figure below shows the result of this import. FINAL 48

49 Figure 31: gbxml import DesignBuilder Despite the more accurate export, windows were not recognized or imported the right way. Most probably due to the fact that the rooms are bounded by structural elements instead of architectural elements. Next to the import-issues, the model contains a large amount of individual spaces, windows and corners. These elements are not all necessary for energy simulations, the analytical basically contains too much information for quick simulations. In order to create a reliable import without the unnecessary data, the rooms were exported as polylines, slightly modified (simplified) and imported using a 2D import. This work around results in a model dedicated for energy simulations. Despite the manual labor, this method proofed to be the most reliable one so far. The next figure shows the result of the geometrical import using the 2D polyline export. Figure 32: import using 2D polyline export FINAL 49

50 8 Performance & Usability The usability of the concept is very important for the practical usefulness of the ELASSTIC BIM concept. During the project we encountered some challenges that are addressed in this section. 8.1 LEVELS OF GEOMETRICAL DETAIL (IFC) The geometry of the IFC BIM models was very detailed for some objects. During the modelling of the data (in Revit, Vectorworks, etc) library components were used that contain a high number of objects with lots of geometrical triangles. For example the railing and fences of the staircases were modelled with round vertical rods. Analysis of the model learned that at one moment the number of geometric triangles used in the staircase objects was more than all other IFC objects from the rest of the model together. This situation made it impossible for some simulation models to perform a simulation. E.g. the staircase geometry in the previous example made it impossible for Siemens to perform an evacuation simulation. Also the explosion simulation from TNO couldn t handle objects that were not cube shaped. During the project this was solved in two ways: - Creating a simplifier support service that simplified the geometry of the model before triggering the simulation services. More about this in chapter Creating a high quality IFC filter language that made it possible to query the model for only objects (and geometry) that was needed for the simulation. 8.2 SCALABILITY OF SIMULATIONS (IN RELATION TO PROCESS) The ELASSTIC BIM concept flourishes best when the results from the simulations are available within a short timeframe. Only with almost seamlessly instant feedback the design can be evaluated during the (early) design process. The results from the simulations are the base of the Multi Criteria Analyses (MCA) to see how the design scores on Key Performance Indicates (KPI s). The runtime of the simulations should therefore be as short as possible. During the ELASSTIC project the simulation for structural integrity (Earthquake simulation) took almost 2 weeks to run. This is not compliant with the ELASSTIC BIM concept where simulation results feed the designer to improve the design instantly. During this project the simulation tools were not optimised for performance, but it is acknowledged that this is needed to have a workable concept. Note: for the structural integrity /reliability simulation, a workaround was created. This remote service ( bot ) was only triggered when the structural object in the new revision were actually changed. The structural integrity simulation only used structural elements of the building. When they were not changed compared to the previous revision the simulation was not triggered. This check was done with a newly created modelcheck plugin. This plugin is available in the BIMserver code repository. FINAL 50

51 8.3 VISUALISATION OF RESULTS To use the ELASSTIC BIM concept in a pure form, there is no need to visualize anything in the BIM model. The results of the simulation feed the MCA calculation and the performance of the design is shown in predefined KPI s. Most of the project members found this disturbing and it wasn t very usable to check the simulation results during the research. Therefore a plugin framework was developed in the bimvie.ws code base. By returning a JSON file as extended data with a revision, the bimvie.ws visualization plugin would recognize it and read it. An example of the JSON structure required to trigger the visualization plugin, and the result in the viewer can be seen in the pictures below: Figure 33: Structure of the JSON data for use of additional visualisation in bimvie.ws FINAL 51

52 Figure 34: Impression of the 'broken windows' as an overlay over the original IFC data FINAL 52

53 9 Link to MCA Storing results from the simulations is important to compare the results to each other. For this comparison the Multi Criteria Analyses (MCA) technology is used. 9.1 STRUCTURING EXTENDED DATA At the ELASSTIC project we agreed to store the results of the simulation tools in the BIM gateway (BIMserver). This was done as extended data with the associated revisions. The team had to define a structure to store the results (reports) of each simulation. It was decided to structure it according to this schema: BIM Server o ELASSTIC project (Ribbon x) revision 1 Extended data o Model_Explosion o Model_Flooding o o Model_MCA revision 2 Extended data o Model_Explosion o Model_Flooding o o Model_MCA revision 3 Extended data o Model_Explosion o Model_Flooding o o Model_MCA The extended data was agreed to be stored as JSON data. Most of the results from the simulation tools were already provided in this syntax. The MCA tools can connect to BIMserver to query the IFC data, and the needed extended data associated with the revision. 9.2 PREPROCESSING DATA TO FACILITATE MCA During the project the MCA developers requested to also receive a notification when all relevant simulation results where available. Since BIMserver doesn t require the simulation models to send back a result, there is no warranty this will ever happen. During the project the following loop was introduced as an internal service: - Data from simulation result comes into BIMserver as extended data - Internal service of BIMserver triggers FINAL 53

54 - Internal service checks if there is the same number of extended data files as there are external notifications send out. If not nothing happens; if yes the next step: - Internal service gets data from the individual extended data files and puts it into a new (single) extended data file on the main project level - This new extended data triggers a notification that is send to the MCA tool This setup proves the flexibility and extendibility of the ELASSTIC BIM concept. 9.3 POST PROCESSING DATA TO FACILITATE MCA The MCA tool for ELASSTIC doesn t only require data from the simulation tools, but also needs information about the building itself. This could be the ratio between usable area and technical area, number of building storeys, etc. This information is not available as an attribute in the IFC data, but can be derived from the data. To facilitate the MCA tool, BIMserver created an internal service that analyses the IFC data and calculates the information required for the MCA tool. This information is stored in a JSON file as extended data (just as the simulation results). Another example where BIMserver facilitated the MCA tool is by creating a custom made serializer for the MCA tool to visualize the building inside the MCA tool using the CesiumJS platform. Figure 35: impression of the custom made serializer for the MCA tool FINAL 54

55 10 Observed and potential process innovation The ELASSTIC BIM concept proved to have great potential to the industry. Due to the automation of simulation models (with or without supporting services) the designer is provided with direct feedback of the performance of the building during the (early) design phase. To optimize the usability of this concept additional features are introduced like model-checking, preprocessing of data (called supporting services in this report), post processing of data (in this project to facilitate the MCA tool), advanced query/filter functions, etc. These additional features facilitate the usability for simulation tools to use the ELASSTIC BIM concept, and BIM in general. FINAL 55

56 11 Discussion and conclusion The ELASSTIC project provided the following conclusions about the ELASSTIC BIM concept, the experiments and BIM in the industry: 1) There are numerous possibilities with the concept of automating simulations based on BIM data. At this moment there are still a lot of manual steps necessary. The potential of the concept is proven, but bringing it to (daily) practice will still be a big challenge. 2) These innovations are only possible with stable open standards (both data and API) and modelling agreements. During this project modelling agreements were made in the beginning of the project, but not honoured during the implementation. Several elements of the IFC where not usable for the simulation models. Good modelling and good export settings are an absolute requirement to use BIM in general, but the automated simulation concept of ELASSTIC in particular. The use of open standards like the BIMSie API and the IFC data standard have proven to work when modellers keep to the agreements during the modelling of the BIM in the native software tools. 3) Not all software tools in the industry have the capability to support open BIM standards. We recommend every software vendor to support import and export of IFC. 4) The spread out use of classifications caused a problem with running simulations. The models in the project contained at least three different classifications (a French one, Omniclass and NlSfb). The use of multiple classification methods for objects in BIM is not a problem (and sometimes even recommended), but in this case only parts of the model were classified. Different parts were classified with different classification methods and there was no overlap between it. We highly recommend to classify as much objects as possible, with as many classification systems as needed. The accent is on the words possible and needed. 5) Different simulation tools need different data as input; structured in a different way. Advanced BIM users in the industry know this and export several IFC files with different export settings for different collaboration partners. The ELASSTIC BIM concept doesn t imply knowledge of the input requirements of simulation tools. Therefore there has to be one export setting to facilitate all simulation models. Use of pre- and post-processing services could contribute to the usability, but this still has to be proven in practical use-cases with large amounts of data and different time scales in execution. Based on these conclusions, we suggest and recommend further use of the concept in the industry. FINAL 56

57 12 Acknowledgment This project has received funding from the European Union s Seventh Framework Programme for research, technological development and demonstration under grant agreement no PROJECT PARTICIPANTS: TNO NEDERLANDSE ORGANISATIE VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK (NL) ARCADIS NEDERLAND BV (NL) FRAUNHOFER-INSTITUT EMI (DE) INSTITUTO CONSULTIVO PARA EL DESARROLLO SL (ES) JA JOUBERT ARCHITECTURE (NL) NORTH BY NORTH WEST ARCHITECTES SARL (FR) SCHÜΒLER-PLAN INGENIEURGESELLSCHAFT MBH (DE) SIEMENS AG (DE) UNIRESEARCH BV (NL) Disclaimer The FP7 project has been made possible by a financial contribution by the European Commission under Framework Programme 7. The Publication as provided reflects only the author s view. Every effort has been made to ensure complete and accurate information concerning this document. However, the author(s) and members of the consortium cannot be held legally responsible for any mistake in printing or faulty instructions. The authors and consortium members retrieve the right not to be responsible for the topicality, correctness, completeness or quality of the information provided. Liability claims regarding damage caused by the use of any information provided, including any kind of information that is incomplete or incorrect, will therefore be rejected. The information contained on this website is based on author s experience and on information received from the project partners. FINAL 57