bim in elasstic

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: MARJOLIJN VERSTEEGDEN (ARCADIS)

WOLFRAM KLEIN (SIEMENS)

APPROVED BY: COORDINATOR – ANS VAN DOORMAAL (TNO)

DELIVERABLE REPORT

DELIVERABLE N0: D2.5

DISSEMINATION LEVEL: PUBLIC

TITLE: REPORT ON IMPROVED USAGE OF BIM TECHNOLOGY

GRANT AGREEMENT NUMBER: 312632

PROJECT TYPE: FP7-SEC-2012.2.1-1 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: WWW.ELASSTIC.EU

TECHNICAL COORDINATION TNO (NL) (WWW.TNO.NL)

PROJECT ADMINISTRATION UNIRESEARCH (NL) (WWW.UNIRESEARCH.NL)

D2.5 | REPORT ON IMPROVED USAGE OF BIM TECHNOLOGY

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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


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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


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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, pre-

processing 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.


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Contents

Executive Summary .................................................................................................................................... 2

Contents ...................................................................................................................................................... 5

1 Introduction / background .................................................................................................................... 7

2 About BIM .............................................................................................................................................. 9

2.1 The Concept and history ............................................................................................................... 9

2.2 Data standards ............................................................................................................................ 10

2.3 BIMserver .................................................................................................................................... 10

3 BIM data in ELASSTIC ........................................................................................................................ 12

3.1 Analyses of BIM data .................................................................................................................. 12

4 ELASSTIC technology concept .......................................................................................................... 17

4.1 The ELASSTIC BIM concept: Integration of Technologies .......................................................... 17

4.2 IT architecture ............................................................................................................................. 18

1.1.1 Linking to building Management system and sensor information .............................. 19

4.3 Design Evaluation ....................................................................................................................... 20

4.4 Innovation.................................................................................................................................... 20

5 ELASSTIC data flow ............................................................................................................................ 23

5.1 Simulation models ....................................................................................................................... 23

5.2 Domain specific requirements ..................................................................................................... 23

5.3 Classifications ............................................................................................................................. 23

5.4 Model view definitions (MVD) ...................................................................................................... 24

5.5 Supporting tools .......................................................................................................................... 26

1.1.2 BIMserver.org ............................................................................................................ 26

1.1.3 Model checking ......................................................................................................... 27

1.1.4 Data transformation services..................................................................................... 27

6 ELASSTIC BIM gateway ...................................................................................................................... 29

6.1 Process inside BIMserver............................................................................................................ 29

6.2 Setting up a notification/trigger .................................................................................................... 30

6.3 Process outside BIMserver ......................................................................................................... 32

6.4 External service (‘bot’) running .................................................................................................... 32

1.1.5 Query language ......................................................................................................... 32

6.5 Remote data coming back........................................................................................................... 32

6.6 Log of ELASSTIC workflow ......................................................................................................... 33

6.7 The ELASSTIC setup .................................................................................................................. 33

7 The ELASSTIC Simulation models .................................................................................................... 37

7.1 Triggering the simulation models ................................................................................................ 37

7.2 Explosion simulation (TNO)......................................................................................................... 37


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1.1.1 IFC model of the building .......................................................................................... 38

1.1.2 Recognition of different objects and its characteristics .............................................. 39

1.1.3 Determination of the façade: ..................................................................................... 39

1.1.4 Results and visualisation ........................................................................................... 41

7.3 Pedestrian stream (Siemens) ...................................................................................................... 42

7.4 Earthquake (Schüßler-Plan) ........................................................................................................ 45

7.5 Structural simulations .................................................................................................................. 45

1.1.5 Structural design calculation ..................................................................................... 45

1.1.6 Wind load structural simulation ................................................................................. 47

7.6 Energy simulation ........................................................................................................................ 48

8 Performance & Usability ..................................................................................................................... 50

8.1 Levels of geometrical detail (IFC) ................................................................................................ 50

8.2 Scalability of simulations (in relation to process) ......................................................................... 50

8.3 Visualisation of results ................................................................................................................ 51

9 Link to MCA ......................................................................................................................................... 53

9.1 Structuring extended data ........................................................................................................... 53

9.2 Preprocessing data to facilitate MCA .......................................................................................... 53

9.3 Post processing data to facilitate MCA ........................................................................................ 54

10 Observed and potential process innovation ..................................................................................... 55

11 Discussion and conclusion ................................................................................................................ 56

12 Acknowledgment ................................................................................................................................. 57

Appendix 1 IFC entities in the ELASSTIC Ribbon model ................................................................ 58

Appendix 2 Event log flow of ELASSTIC BIM gateway .................................................................... 61

Appendix 3 Literature list ................................................................................................................... 63


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1 Introduction / background


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.



- Simulation models


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.


evaluate safety and security of the building design. The link to the MCA tool is elaborated in chapter 9.


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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.






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.


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2 About BIM

2.1 THE CONCEPT AND HISTORY


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.


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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 12.000

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.


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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:


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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

(19.188.069). 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:

3.285.133 cartisian points;

5.019.418 IFC faces;

The most used IFC object IfcPolyLoop: 5.019.433 occurrences.

The IfcClassification object is only used 15 times.

An overview of the classes:


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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.


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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 57016 171048

Ribbon 0 - Construction 3744782 11234346

Ribbon 0 - MEP 2208 6624

Ribbon 1 - Architecture 190154 570462


Ribbon 1 - MEP 10384 31152



Ribbon 2 - MEP 12788 38364



Ribbon 3 - MEP 384 1152



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Ribbon 4 - MEP 148 444

Total: 6.639.882 19.919.646

This shows that the construction models are by far the most detailed in geometry.


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4 ELASSTIC technology concept

An overview of the technology in the ELASSTIC project.

4.1 THE ELASSTIC BIM CONCEPT: INTEGRATION OF TECHNOLOGIES



- Simulation models


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.


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




evacuation simulation. The location of the fire, and maybe intensity are available data at this moment in the


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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.






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.


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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.

1.1.1 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)


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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.


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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.


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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.


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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


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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 12.000 properties defined.


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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.


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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.

1.1.2 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.


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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.

1.1.3 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.

1.1.4 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).


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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.


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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.


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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.

User check-in of

new data

Modelcheck by

server (1)

Check-in refused

Me

ssa

ge

se

nd

to

use

r

Not OK?

OK

New revision is

created

Modelcheck by

server (2)

Not OK?

OK

Notification is send to

subscribed service

No services subscribed?

Se

rvic

es

su

bscrib

ed


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The steps that are needed to setup a trigger and send out a remote service are the following:

Figure 12: process to setup a trigger in a BIMserver

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 chooses known public

profile

User provides token of remote service user

to choose private profile

BIMserver administrator

adds allowed data schema

User configures access rights

(links access rights to send out token)

BIMserver gets modelchecking snippets

from online repository

User chooses (one or more) modelchecking

snippets

BIMserver sets the

trigger as configured


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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.

1.1.5 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.


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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:


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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.


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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


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


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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 5.3.1 in deliverable D2.4.

In the ELASSTIC project it is agreed that the BIMserver is the portal to the simulation models.


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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.

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.

1.1.1 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.

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


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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.

1.1.2 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 2000’. 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.

1.1.3 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


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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.


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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


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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


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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:

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

• 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)


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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,

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:

Figure 24: process


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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.

1.1.5 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


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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.


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Figure 27: Result of the exported model in SCIA Engineer

1.1.6 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


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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.


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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


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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 6.7

- 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.


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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


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


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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


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- 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


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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, pre-

processing 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.


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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.


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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 312632”.

http://cordis.europa.eu/fp7/cooperation/home_en.html

http://ec.europa.eu

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.

http://cordis.europa.eu/fp7/cooperation/home_en.html

http://ec.europa.eu/


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Appendix 1 IFC entities in the

ELASSTIC Ribbon model

IFC Entities Occurances

IfcBeam 1151

IfcBuilding 15

IfcBuildingElementProxy 387

IfcBuildingStorey 263

IfcColumn 1222

IfcCovering 19

IfcDistributionControlElement 67

IfcDistributionPort 28

IfcDoor 2041

IfcFlowFitting 8

IfcFlowSegment 111

IfcFooting 2459

IfcGroup 186

IfcMember 533

IfcOpeningElement 10737

IfcProject 15

IfcSite 15

IfcSlab 764

IfcSpace 1170

IfcStair 332

IfcStairFlight 339

IfcSystem 3

IfcWall 80

IfcWallStandardCase 9724

IfcWindow 2526

IFC Relations Occurances

IfcRelAggregates 456

IfcRelAssignsToGroup 189

IfcRelAssociatesClassification 7310

IfcRelAssociatesMaterial 12728

IfcRelConnectsPathElements 12283

IfcRelConnectsPortToElement 28

IfcRelConnectsPorts 14

IfcRelContainedInSpatialStructure 258

IfcRelCoversBldgElements 11

IfcRelDefinesByProperties 65137

IfcRelDefinesByType 2051


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IfcRelFillsElement 4566

IfcRelServicesBuildings 3

IfcRelSpaceBoundary 18352

IfcRelVoidsElement 10737

Rest Occurances

IfcApplication 15

IfcArbitraryClosedProfileDef 1592

IfcArbitraryProfileDefWithVoids 27

IfcAxis2Placement2D 24441

IfcAxis2Placement3D 120865

IfcBooleanClippingResult 3358

IfcBooleanResult 6

IfcBuildingElementProxyType 387

IfcCartesianPoint 3285133

IfcCartesianTransformationOperator3D 15

IfcCircle 499

IfcCircleHollowProfileDef 4

IfcCircleProfileDef 263

IfcClassification 15

IfcClassificationReference 7310

IfcClosedShell 8131

IfcColourRgb 112

IfcColumnType 1222

IfcCompositeCurve 142

IfcCompositeCurveSegment 1867

IfcConnectionSurfaceGeometry 34287

IfcConversionBasedUnit 15

IfcCurveBoundedPlane 34287

IfcDerivedUnit 43

IfcDerivedUnitElement 127

IfcDimensionalExponents 15

IfcDirection 2046

IfcDoorLiningProperties 57

IfcDoorPanelProperties 43

IfcDoorStyle 57

IfcDuctFittingType 5

IfcDuctSegmentType 4

IfcExtrudedAreaSolid 25561

IfcFace 5019418

IfcFaceBound 15

IfcFaceOuterBound 5019418

IfcFacetedBrep 8131

IfcGeometricRepresentationContext 15


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IfcGeometricRepresentationSubContext 60

IfcHalfSpaceSolid 902

IfcIShapeProfileDef 286

IfcLocalPlacement 33991

IfcMappedItem 6784

IfcMaterial 101

IfcMaterialDefinitionRepresentation 94

IfcMaterialLayer 112

IfcMaterialLayerSet 87

IfcMaterialLayerSetUsage 10406

IfcMaterialList 2229

IfcMeasureWithUnit 15

IfcMemberType 305

IfcOrganization 30

IfcOwnerHistory 15

IfcPerson 15

IfcPersonAndOrganization 15

IfcPipeSegmentType 6

IfcPlane 37647

IfcPolyLoop 5019433

IfcPolygonalBoundedHalfSpace 2458

IfcPolyline 54995

IfcPostalAddress 15

IfcPresentationLayerAssignment 86

IfcPresentationStyleAssignment 717

IfcProductDefinitionShape 33338

IfcPropertySet 65316

IfcPropertySingleValue 55920

IfcRectangleProfileDef 23389

IfcRepresentationMap 2000

IfcSIUnit 252

IfcSensorType 6

IfcShapeRepresentation 46293

IfcStyledItem 22576

IfcStyledRepresentation 94

IfcSurfaceStyle 112

IfcSurfaceStyleRendering 112

IfcTrimmedCurve 499

IfcUnitAssignment 15

IfcWallType 41

IfcWindowLiningProperties 18

IfcWindowStyle 18


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Appendix 2 Event log flow of ELASSTIC

BIM gateway


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Appendix 3 Literature list

Beetz, Jakob; de Laat, Ruben; van Berlo, Léon; van den Helm, Pim; ,Towards an open building information model server,"Proc. of the 10th International Conference on Design & Decision Support Systems in Architecture and Urban Planning, The Netherlands",,,,2010,

Beetz, Jakob; van Berlo, Léon; de Laat, Ruben; van den Helm, Pim; ,BIMserver. org–An open source IFC model server,Proceedings of the CIP W78 conference,,,,2010, Berlo, LAHM van; Beetz, J; Bos, P; Hendriks, H; van Tongeren, RCJ; ,Collaborative engineering with IFC: new insights and technology,"Proceedings of the 9th European Conference on Product and Process Modelling 2012 ECPPM, Reykjavik, 25-27 July",,,10,2012,

Berlo, LAHM van; Bomhof, F; ,Creating the Dutch national BIM levels of development,,,,,2014,American Society of Civil Engineers (ASCE)

Berlo, Léon van; Krijnen, Thomas; ,Using the BIM Collaboration Format in a Server Based Workflow,Procedia Environmental Sciences,22,,325-332,2014,Elsevier

Berlo, Léon van; Derks, Gijs; Pennavaire, Cyrille; Bos, Paul; ,Collaborative engineering with IFC: common practice in the Netherlands,"Proc. of the 32nd CIB W78 Conference 2015, October 27th-29th 2015, Eindhoven, The Netherlands",,,,2015,

Manzione, L; Wyse, M; Sacks, R; Van Berlo, L; Melhado, SB; ,Key Performance Indicators To Analyze And Improve Management of Information Flow In The BIM Design Process,"CIB W78-W102 2011: International Conference, France",,,,2011,

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