Effective Context-based BIM Style Description (BSD) of Query Results

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1 Effective Cotext-based BIM Style Descriptio () of Query Results Tae Wook Kag ICT Lab. Korea Istitute of Costructio Techology Seoul, South Korea Abstract The purpose of this study is to develop a effective Buildig Iformatio Modelig (BIM) query visualizatio style descriptio ad a method for utilizig it based o cotext. Such BIM would ifluece usability i visualizig query results accordig to a user s use case cotext after queryig the objects required from a BIM database. This study proposes a cotext-based structure for BIM style descriptio () of query results ad a laguage that defies it effectively. The proposed is demostrated through a case study, ad coclusios are derived. Keywords-BIM; Query Laguage; Cotext; Visualizatio Style;. I. INTRODUCTION Buildig Iformatio Modelig (BIM) techology is a 3D-based buildig object database (DB) modelig ad utilizatio techology specialized for the architecture, egieerig, ad costructio (AEC) idustries. BIM ca be actively applied to ustructured buildig desigs ad buildig member prefabricatio. Recetly, BIM techology has bee used to coduct various studies o buildig Facility Maagemet (FM), Buildig Automatio Systems (BASs), Buildig Eergy Maagemet Systems (BEMSs), ad Geographic Iformatio Systems (GISs) for Smart Buildig ad Urba Maagemet (SBUM). This is because problems that caot be solved by existig FM, BAS, BEMS, ad GIS systems could be effectively addressed if 3D buildig object DB iformatio from the BIM were well coverged. For BIM-based SBUM, BIM DB iformatio must be queried effectively, ad the queried results must be visualized accordig to the use case cotext for users. I particular, processig ad visualizig the queried results accordig to the use case cotext ca ifluece the usability of the BIM-based SBUM system. However, few studies related to this area have bee coducted because BIM techology is relatively ew, ad FM, BAS, ad BEMS, as well as techologies for itegratio ad utilizatio of their iformatio have emerged withi the last two to three years. This study proposes a cotext-based structure that ca effectively visualize queried results obtaied from the BIM DB by a user accordig to the use case cotext, ad a laguage that ca defie the structure effectively. The proposed is demostrated through a case study, ad coclusios are derived. Here, cotext-based refers to a method for displayig queried iformatio effectively i various Hyu Sag Choi ICT Lab. Korea Istitute of Costructio Techology Seoul, South Korea hyusag@kict.re.kr applicatio cotexts based o BIM. For example, i some applicatios, oly importat query results amog all results are preferred to be displayed o a scree. Furthermore, a represetatio mode (color, visualizatio style, etc.) for certai results may be emphasized depedig o the cotext i which a user searches the virtual space. The cotextbased mode supports these features, so that it ca help users to recogize query results effectively i BIM iformatio that icludes a large umber of BIM objects ad make a decisio. We described the cotet for research as follows. 1.The Itroductio sectio describes research backgroud ad motivatio. 2.The Study methodology sectio describes the study workflow. 3.The Related literature review surveys the recet research. 4.The Developmet of the query result structure sectio describes the method desig. 5.The Implemetatio case study sectio develops the prototype to validate. 6.The Discussio sectio describes the beefits of 7.The Coclusio ad future work sectio explais the results of our study ad draws coclusios. II. STUDY METHODOLOGY The research scope of this study is the developmet of a cotext-based structure. The study s coclusios are derived through case studies. Defiitio of research scope BIM DB structure aalysis laguage defiitio Implemetatio case studies structure developmet cotext defiitio Figure 1. Research-related literature review BIM DB query method defiitio Discussio Research flow. BIM DB query laguage defiitio Coclusio 65

2 The study method is show i Fig. 1. The differetiatio of this study ca be derived by reviewig the research scope ad related literature. For structure developmet, first, the Idustry Foudatio Classes (IFC)-based BIM DB structure is aalyzed, ad a simplified BIM query laguage structure is developed. The, the cotext-based laguage is defied ad coclusios are derived via the implemetatio of case studies. III. RELATED LITERATURE REVIEW Studies related to BIM DB queries were coducted to develop query methods i accordace with their utilizatio purpose, ad they are based o the IFC DB proposed by buildigsmart alliace [8] or o commercial buildig modelig system DBs, such as Autodesk Revit [11] ad Graphisoft ArchiCAD software [12]. Research o object iteractio query [1] proposed a Query Volume (QV) method that is specialized for the purpose of buildig desig. Research o automated extractio from ad queryig of the BIM DB [2] proposed a buildig compoet query, locatio query, ad space query for the BIM DB query operatios, ad implemeted them. Research o spatio-sematic cosistecy checkig for the BIM DB [3] proposed a sematically queryable measure for buildig spaces. Research o the spatial query laguage [4] defied the operators for space query of GIS ad buildig objects, ad developed a viewer that ca perform space queries with regard to objects represeted by CityGML [9]. Research o costructio-specific spatial iformatio [5] proposed a query laguage that ca check costructability from the desiged buildig model iformatio. Aother study o the GIS model iformatio represetatio proposed olie mappig [6] usig HTML5. I that study, GIS model iformatio was represeted graphically usig HTML5. I a study o theme-based mappig ad graphical represetatio of GIS model iformatio [7], the directio for the cocept of the Extesible Markup Laguage (XML) theme-based graphic symbol creatio ad its extesio were proposed. May studies related to this are based o GIS. The literature review related to the preset study shows that most research focused o query methods ad laguage developmet for buildig object query, desig itetio check, space check, ad costructability. However, few studies have bee coducted o a method for effectively visualizig queried results from the BIM DB accordig to the use case cotext, ad there is o related tool to perform this. I additio, the developmet of BIM techology is still uderway. Noetheless, few studies have bee doe o how to express query results for BIM shape ad attributes effectively. IV. DEVELOPMENT OF THE QUERY RESULT STRUCTURE A. Aalysis of the BIM DB structure The BIM DB i this study is based o the IFC [10]. The IFC is a BIM iteratioal stadard file format that ca represet a buildig structure as relatioships amog buildig objects, such as buildig, story, slab, floor, colum, door, ad widow. The IFC is stored i EXPRESS or XML mode, ad verificatio rules are defied for each object class i order to coduct object iformatio itegrity checks. Recetly, buildigsmart preseted IFC4 that improved the extedibility of file formats ad removed ambiguity. The IFC ca search a etire IFC object hierarchy structure ad extract required iformatio usig the IfcProject object that defies a buildig project. Each object ca search topological iformatio i relatio to the correspodig object through the IfcRelatioship of the IfcObjectDefiitio. The IfcRelatioship is redefied as it is derived ito classes of IfcRelAggregates or IfcRelCotaiedISpatialStructure, depedig o the type of relatioship with the objects. These classes represet whole/part ad referece relatioships betwee objects. The relatioships that are used most to search the IFC objects are Relatig/Related, Decomposed, Cotaied, ad Refereced. The buildig space ad member objects have a iclusio relatioship with each other. For example, IfcBuildig that icludes IfcProject icludes a aggregate relatioship of IfcBuildigStorey usig the IfcRelAggregates object. Coversely, IfcBuildigStorey refereces objects, i which they are icluded, as a iverse relatioship (INV). IfcBuildigStorey maages IfcProduct usig the relatioship object called IfcRelCotaiedISpatialStructure. Fig. 2 shows the IfcBuildig class relatioship. Figure 2. IfcBuildig classes relatioship [10] The IFC stores buildig iformatio as shape iformatio ad attribute iformatio. The shape iformatio is recorded i boudary represetatio (B-Rep) format or parametric-based primitive format. If the IFC 66

3 shape iformatio is aalyzed, space-based objects ca be queried. The attribute iformatio is provided via IfcPropertySet i associatio with objects. A object ca be related to multiple attribute sets. IfcPropertySet has IfcProperty which maages idividual attributes. Therefore, a attribute value of a particular object ca be acquired via access to IfcProperty; i additio, a object with a specific attribute value ca be searched. I IFC2x3, the IFC structure cosists of more tha 700 classes based o extedibility. This is highly complex because it defies relatioships betwee classes sematically. I this paper, the Simple BIM (SBIM) DB structure show i Fig. 3 was desiged to make queryig of IFC DB iformatio more coveiet. ObjectType PropertyType -DefaultValue: strig -Type: eum{iteger, real, strig, list, table} PropertyTypeSet Property -Name: strig -Value: strig SBIM DB Creatio SBIM Query Process IFC File IFC Parser SBIM DB Coverter SBIM DB Query strig SBIM Query results Figure 4. SBIMql Query Egie Processor File BIM DB query process. SBIM Query results Cotext-based Results C. Defiitio of the BIM DB query laguage I this study, Simple BIM DB Query Laguage (SBIMql) is developed to defie a iformatio query format for SBIM DB. SBIMql uses a toke aalyzer ad a parser geerator such as LEXical aalyzer (Lex) or Yet Aother Compiler Compiler (YACC) i order to check sytax errors automatically. The laguage structure is defied as beig similar to that of Structured Query Laguage (SQL). The SBIMql defiitio for YACC is as follows: Cotai -Associatio Variable : PROPERTY_NAME Shape Figure 3. Object -Name: strig Simple BIM DB architecture. PropertySet -Name: strig B. Defiitio of the BIM DB query method For a BIM DB query, IFC is parsed to be stored i the simple BIM DB structure. Buildig classes such as slab, wall, ad widow are mapped to objects, whereas types of buildig classes are mapped to ObjectType. A Whole/Part structure of a object is represeted by a Cotai Relatioship. Other relatioships ca be represeted by a Associatio Relatioship. Sice Object classes ad ObjectType classes have a Depedecy relatioship, a specific buildig elemet ca be queried. I additio, Object classes iclude PropertySet classes such that objects with a specific attribute value ca be searched. Searchig accordig to object relatioships ca be doe usig the Cotai ad Associatio relatioships. Fig. 4 shows the BIM DB query process, icludig processig. Value : STRING CoditioOP : = < > <= >= Fuc : IsI IsCross IsOut SimpleExpressio : Variables CoditioOP Value LogicOp : AND OR Expressio : SimpleExpressio SimpleExpressio LogicOp Expressio Usig SBIMql, the followig query ca be defied sytactically. SELECT FROM IfcObject WHERE Type=IfcWidow AND Name= Widow xyz 67

4 The issue described i the previous paragraph ca be defied as a problem of mappig elemets i the query results (QR) set ito the cotext-based QR (CQR) described by the cotext-based, as show i Fig. 6. As ca be see from Fig. 6, plays a role as a coversio fuctio betwee sets. The cosists of a umber of BIM styles (BSs) of query results that defie the view style of the query result. Depedig o the cotext i which the BS is applied, a attribute ad shape style are applied to the BS. The cotext cosists of specific style applicatio coditios uder which the style is applied. The coditio has filters that defie detailed coditios to process the attribute or shape styles i accordace with the cotext. The attribute style defies how to represet the attribute values i the query result to a user, whereas the shape style defies the materials that are used to visualize the object shape i the query result. The material ca defie color, trasparecy, ad texture. For example, if the cotext is a space program, the color schema ca be developed ad applied accordigly. Table 1 describes the cotext-based defiitio. Figure 5. SBIMql process algorithm. The sematics of this query statemet is for queryig all the objects of Type IfcWidow ad the Name attribute value of Widow xyz. Fig. 5 shows the algorithm of the SBIM query egie that processes SBIMql. D. Defiitio of the Cotext-based structure I order for a user to recogize query results effectively, it is highly importat to support features that provide color schema accordig to attribute values based o the use case cotext while visualizig the query result. It is also importat to emphasize specific objects ad specific values of objects, which iflueces usability directly. To implemet this feature, cotext-based laguage is defied to display SBIMql query results effectively based o the use case cotext. The must support a variety of use case cotexts for users. Figure 6. Set Mappig from QR to CQR. BS Elemet BS BS BS Ctx Desc C C T N F F L Var V V From V To = { Ctx, Desc}, Ctx = Cotext, Desc = Descriptio, F = { F = { BS}, BS = { BS C = { C TABLE I., L}, F, F}, C = { T, N}, = { Var, V, V, C}, From, V To }. CONTEXT-BASED DEFINITION Descriptio BIM query results Style Defiitio BIM Style Defiitio umets of BIM Style like below Ctx = Cotext ame Desc = Descriptio BIM Style Defiitio umets Cotext Defiitio Descriptio Cotext Coditio Defiitio Cotext Coditio umets Cotext-based Coditio Type Cotext-based Coditio Name Cotext-based Coditio Filter Defiitio Filter umets that have a variable, value, ad equatio. Coditio Logic script to describe the BIM Property ad Geometry Trasformatio depedig o Cotext Cotext-based Coditio Filer Variable such as Type, DistaceFromCameraToObjectCeter ad OrderIdex Filter Variable value From value to evaluate the Filter coditio To value to evaluate the Filter coditio (1) (2) (3) (4) 68

5 Fig. 7 shows the algorithm related to rederig the query results cosiderig. Figure 7. process algorithm. Fig. 8 shows the elemets class diagram. It cosists of coditios which ca cotai the filters. The filter cotais the other filter or the logic to represet how to reder the queried BIM product. The filter cosists of Var, V, V, ad From V To to evaluate the coditio. This logic ca be executed whe the coditio icludig the filters is satisfied. Figure 8. elemets class diagram i Uified Modelig Laguage (UML). The followig code is a XML defiitio example to visualize the BIM query iformatio i the cotext of the Space Program Maagemet usig the proposed. <> <BS Cotext="Facility maagemet" Desc="Iformatio highlight"> Coditio Filter Var, V, VFrom, V Logic To <Coditio Type="Property" Name="Legth of object"> <Filter Var="Type" Value="IfcWallStadardCase"> <Filter Var="DistaceFromCameraToObjectCeterPositio" <Logic> </Logic> </Coditio> FromValue="0" ToValue="10"> Value = strig.format("legth of %s = %.2f", Property.PSet("Name"), Property.PSet("Legth")) TextHeight = DistaceFromCameraToObjectCeterPositio <Coditio Type="Geometry" Desc="Object highlight"> <Filter Var="Type" Value="IfcWallStadardCase"> <Filter Var="SortIdex" Value="0"> <Logic> Color = RGB(0.0, 1.0, 1.0, 1.0) </Logic> </Coditio> <Coditio Type="Geometry" Desc="Trasparet schema"> <Filter Var="Type" Value="IfcWallStadardCase"> <Filter Var="DistaceFromCameraToObjectCeterPositio" FromValue="0" ToValue="10"> <Filter Var="SortIdex" ValueFrom="1" <Logic> ValueTo="ifiite"> Ratio = (QR.Cout - SortIdex) / QR.Cout Color = RGB(0.0, 1.0, 0.0, Ratio) </Logic> </Coditio> </BS> </> V. IMPLEMENTATION CASE STUDY SBIMql ad the were implemeted usig the opesource extesible Buildig Iformatio Modelig (xbim) Toolkit for this case study via the cotext-based implemetatio. Note that xbim is a ope-source-based software developmet BIM tool that supports IFC read-adwrite as well as mesh processig usig Ope CASCADE, ad visualizatio via a 3D rederig egie for IFC shape visualizatio. 69

6 Fig. 9 shows a result that performs the SBIMql query statemet SELECT FROM IfcWallStadardCase WHERE IfcWallStadardCase.Legth > Fig. 9 shows the model before (above) ad after (below) the SBIMql query. Cotext-based Coditio ad Logic Script Var = SortIdex If ( Var = 0) Color = RGB(1.0, 1.0, 0.0, 0.0) Var = SortIdex If ( 0 Var < if) Ratio = (QR.Cout - SortIdex) / QR.Cout Color = RGB(0.0, 1.0, 0.0, Ratio) Var = Legth If ( 0 Var < 10000) Color = RGB(0.0, 1.0, 0.0, 1.0) If ( Var < 12000) Color = RGB(0.0, 1.0, 1.0, 1.0) If ( Var < 15000) Color = RGB(0.0, 0.0, 1.0, 1.0) If ( Var < if) Color = RGB(1.0, 0.0, 1.0, 1.0) SBIMql+ results VI. DISCUSSION Figure 9. SBIMql query ad results. The followig code shows the result of applyig the cotext-based accordig to the use case cotext. It was verified that the query result was effectively visualized usig the accordig to the use case cotext. SELECT (, 'Cotext-based.xml') FROM IfcWallStadardCase WHERE IfcWallStadardCase.Legth > 5000' ORDERBY IfcWallStadardCase.Legth Table 2 lists the results for how the SBIMqlprocessed result ca be differet depedig o the cotext coditio. TABLE II. CONTEXT-BASED RESULTS Cotext-based Coditio ad Logic Script Var = DistaceFr omcamerato ObjectCet erpositio Np = Near distace from camera to object ceter positio If ( 0 Var < 15) Value = strig.format("legth of %s = %.2fm", Property.PSet("Name"), Property.PSet("Legth")) TextHeight = DistaceFromCameraToObjectCeterPositio Color = RGB(0.0, 1.0, 0.0, 0.8) Else Value = "" Color = RGB(0.0, 1.0, 0.0, 0.3) Ed SBIMql+ results Np = Np = Np = Np = 9.21 To evaluate the usability of the, a five-poit scale Likert survey was coducted with three BIM practitioers ad three ordiary persos by askig them how much they uderstood the query itetios after showig the results of SBIMql ad SBIMql+. TABLE III. Usability Item Uderstadig (U) easy to uderstad the query result. Search (S) required objects ca be searched quickly. Recogitio (R) iformatio o the scree ca be recogized comfortably. CONTEXT-BASED RESULTS SBIMql SBIMql+ Differece The iterview participats provided positive aswers for the usability, show i Table 3, which distictively demostrate the differece betwee the two groups of SBIMql ad. Particularly, respodets recogized that the improved ability to search for a eeded object withi the queried objects results set. The participats suggested that a icreased variety of operators is required for the, ad that more improvemets are eeded i terms of queries o the BIM objects ad processig performace. There were the discussios related to results such as the meaigs ad effects as described below. First, there are meaigs whe the is used for the object classificatio betwee the BIM products which have similar shapes but differet property values. Secod, the query results ca be uderstood as represetig a object by usig ituitively. It is possible to validate the query results regardless of whether the search result is correct. 70

7 Third, the ca be used to represet the color schema depedig o the property value of the BIM product. Forth, the query results ca be visualized cosiderig the avigatio cotext icludig the variables such as the camera distace from the observed object i the 3D rederig space. However, there were some issues as described below. First, if there are may objects i a BIM model, it seems that the query process performace is slow. I case of this, it is ecessary to improve the performace. Secod, the various operatios such as touch, i, ad out betwee BIM products are eeded to represet the query results cosiderig the model space cotext. I additio, to satisfy the suggested opiios, optimizatio ad efficiet space idexig for SBIMql ad processig are required. VII. CONCLUSION AND FUTURE WORK For cotext-based structure developmet, the IFCbased BIM DB structure was aalyzed, ad a simplified BIM query laguage structure was developed. The proposed i the implemetatio case study showed the feasibility of visualizig query results based o the use case cotext of a user. By usig the proposed method, tools that ca icrease the usability of query results ca be provided to the AEC idustries accordig to various use case cotexts, such as SBUM. The survey results caot be verified statistically, because the umber of the samples was small, which is the limitatio of this study. This limitatio will be overcome i the subsequet study. Moreover, we will exted the mappig operators for the proposed ad study how to aalyze the iformatio graphically i the future. [3] S. Daum ad A. Borrma, Checkig spatio-sematic cosistecy of buildig iformatio models by meas of a query laguage, Thirteeth Iteratioal Coferece o Costructio Applicatios of Virtual Reality, 2013, pp [4] A. Borrma, From GIS to BIM ad back agai a spatial query laguage for 3D buildigs ad 3D city models, Fifth Iteratioal 3D GeoIfo Coferece, 2010, pp [5] M. Nepal, S. Staub-Frech, R. Pottiger, ad A. Webster, Queryig a buildig iformatio model for costructiospecific spatial iformatio, Advaced Egieerig Iformatics, vol. 26, pp , [6] M. N. K. Boulos, W. Jeffrey, G. Jiaya, ad Y. Peg, Web GIS i practice VIII: HTML5 ad the cavas elemet for iteractive olie mappig, Iteratioal Joural of Health Geographics, vol. 9, o. 1, pp. 1 13, [7] T. S. Abso ad E. Olivier, Towards web services dedicated to thematic mappig, OSGeo Joural, vol. 3, o. 1, [8] buildigsmart alliace, [retrieved April 2014] [9] CityGML, [retrieved April 2014] [10] Idustry Foudatio Classes, buildigsmarttech.org/ifc/ifc2x4/rc3/html/idex.htm, [retrieved April 2014] [11] Autodesk Revit, [retrieved April 2014] [12] ArchiCAD, [retrieved April 2014] ACKNOWLEDGMENT This research was supported by a grat from the BIM/GIS Platform-based Costructio Spatial Iformatio Itegratio Operatio Techology Developmet project, which is oe of the mai projects i 2014 of the Korea Istitute of Costructio Techology. REFERENCES [1] C. Soto ad M. Carlsso, Object Iteractio Query: A cotext awareess tool for evaluatig BIM compoets iteractios. bimforum, projects.buildigsmartalliace.org/files/?artifact_id=5372, [2] M. Nepal, Automated extractio ad queryig of costructio-specific desig features from a buildig iformatio model, doctoral thesis, Uiversity of British Columbia,