IFC 4.3.2.20240512 (IFC4X3_ADD2) under development

Annex E
(informative)

Examples

E.1.5 - Cube Advanced Brep

Example overview

The examples demonstrate the use of various geometric shape representation types to express a simple geometric form of an element. The examples of advanced geometric shape deal with CSG having Boolean operations, advanced swept solid and advanced brep representations. in some cases, the same geometry is also provided as faceted brep or tessellation to compare the results.

The advanced brep representation using NURBS is shown in Figure E.B. It shows a twisted cube resulting in b-spline surfaces at four sides. The cube itself is exported as a proxy element.

advanced_brep_2.png
Figure E.B — Advanced shape represented as advanced Brep

IFC-SPF source

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('ViewDefinition [notYetAssigned]'),'2;1');
FILE_NAME(
/* name */ 'cube-advanced-brep.ifc',
/* time_stamp */ '2012-05-31T11:53:44',
/* author */ ('redacted'),
/* organization */ ('redacted'),
/* preprocessor_version */ 'redacted',
/* originating_system */ 'redacted',
/* authorization */ 'None');

FILE_SCHEMA (('IFC4X3_DEV_1cb7015'));
ENDSEC;

DATA;

/* single owner history sufficient if not otherwise required by the view definition ------------ */
/* provides the person and application creating the data set, and the time it is created ------- */
#1= IFCAPPLICATION(#2,'redacted','redacted','redacted');
#2= IFCORGANIZATION($,'redacted',$,$,$);
#3= IFCPERSONANDORGANIZATION(#4,#5,$);
#4= IFCPERSON($,'redacted',$,$,$,$,$,$);
#5= IFCORGANIZATION($,'redacted',$,$,$);
#6= IFCOWNERHISTORY(#3,#1,$,.ADDED.,1338465163,$,$,1338465163);

/* each IFC data set containing geometry has to define a geometric representation context ------ */
/* the attribute 'ContextType' has to be 'Model' for 3D model geometry ------------------------- */
#7= IFCCARTESIANPOINT((0.0,0.0,0.0));
#8= IFCDIRECTION((1.0,0.0,0.0));
#9= IFCDIRECTION((0.0,1.0,0.0));
#10= IFCDIRECTION((0.0,0.0,1.0));
#11= IFCAXIS2PLACEMENT3D(#7,#10,#8);
#12= IFCAXIS2PLACEMENT2D(#13,$);
#13= IFCCARTESIANPOINT((0.0,0.0));
#14= IFCAXIS2PLACEMENT3D(#7,#10,#8);
#15= IFCGEOMETRICREPRESENTATIONCONTEXT('Body','Model',3,0.00001,#14,#16);
#16= IFCDIRECTION((0.0,1.0));

/* each IFC data set containing geometry has to define at absolute minimum length and angle ---- */
#17= IFCSIUNIT(*,.LENGTHUNIT.,$,.METRE.);
#18= IFCSIUNIT(*,.AREAUNIT.,$,.SQUARE_METRE.);
#19= IFCSIUNIT(*,.VOLUMEUNIT.,$,.CUBIC_METRE.);
#27= IFCSIUNIT(*,.PLANEANGLEUNIT.,$,.RADIAN.);
#26= IFCUNITASSIGNMENT((#17,#18,#19,#27));

/* each IFC data set containing elements in a building context has to include a building ------- */
/* at absolute minimum (could have a site and stories as well) --------------------------------- */
#25= IFCPROJECT('2oT9YYbSrBUghtexcAcblU',#6,'Grasshopper Project',$,$,'Grasshopper Project',$,(#15),#26);
#21= IFCBUILDING('3qzoyCPy1CtfV237Rle9$t',#6,'Grasshopper Building','GH Building',$,#22,$,$,.ELEMENT.,$,$,$);
#22= IFCLOCALPLACEMENT($,#11);
#23= IFCRELCONTAINEDINSPATIALSTRUCTURE('0LkkopPYL7VANMLhZDjkkq',#6,'Building','Building Container for Elements',(#181),#21);
#28= IFCRELAGGREGATES('2C1MZiLqv228Cmw2sZ7QPO',#6,'Project Container','Project Container for Buildings',#25,(#21));

/* geometry definition of the advanced brep ---------------------------------------------------- */
/* previded as the 'AdvancedBrep' representation type for the 'Body' of a building element proxy */
#29= IFCCLOSEDSHELL((#104,#115,#131,#147,#163,#179));
#30= IFCVERTEXPOINT(#31);
#31= IFCCARTESIANPOINT((-0.5,-0.5,0.0));
#32= IFCVERTEXPOINT(#33);
#33= IFCCARTESIANPOINT((0.5,-0.5,0.0));
#34= IFCVERTEXPOINT(#35);
#35= IFCCARTESIANPOINT((0.5,0.5,0.0));
#36= IFCVERTEXPOINT(#37);
#37= IFCCARTESIANPOINT((-0.5,0.5,0.0));
#38= IFCVERTEXPOINT(#39);
#39= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#40= IFCVERTEXPOINT(#41);
#41= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#42= IFCVERTEXPOINT(#43);
#43= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#44= IFCVERTEXPOINT(#45);
#45= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#46= IFCCARTESIANPOINT((-0.5,0.5));
#47= IFCCARTESIANPOINT((-0.5,-0.5));
#48= IFCPOLYLINE((#47,#46));
#49= IFCEDGECURVE(#30,#36,#48,.T.);
#50= IFCCARTESIANPOINT((-0.5,-0.5));
#51= IFCCARTESIANPOINT((0.5,-0.5));
#52= IFCPOLYLINE((#51,#50));
#53= IFCEDGECURVE(#32,#30,#52,.T.);
#54= IFCCARTESIANPOINT((0.5,-0.5));
#55= IFCCARTESIANPOINT((0.5,0.5));
#56= IFCPOLYLINE((#55,#54));
#57= IFCEDGECURVE(#34,#32,#56,.T.);
#58= IFCCARTESIANPOINT((0.5,0.5));
#59= IFCCARTESIANPOINT((-0.5,0.5));
#60= IFCPOLYLINE((#59,#58));
#61= IFCEDGECURVE(#36,#34,#60,.T.);
#62= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#63= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#64= IFCPOLYLINE((#63,#62));
#65= IFCEDGECURVE(#38,#44,#64,.T.);
#66= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#67= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#68= IFCPOLYLINE((#67,#66));
#69= IFCEDGECURVE(#40,#38,#68,.T.);
#70= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#71= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#72= IFCPOLYLINE((#71,#70));
#73= IFCEDGECURVE(#42,#40,#72,.T.);
#74= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#75= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#76= IFCPOLYLINE((#75,#74));
#77= IFCEDGECURVE(#44,#42,#76,.T.);
#78= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#79= IFCCARTESIANPOINT((-0.5,-0.5,0.0));
#80= IFCPOLYLINE((#79,#78));
#81= IFCEDGECURVE(#30,#44,#80,.T.);
#82= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#83= IFCCARTESIANPOINT((0.5,-0.5,0.0));
#84= IFCPOLYLINE((#83,#82));
#85= IFCEDGECURVE(#32,#42,#84,.T.);
#86= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#87= IFCCARTESIANPOINT((0.5,0.5,0.0));
#88= IFCPOLYLINE((#87,#86));
#89= IFCEDGECURVE(#34,#40,#88,.T.);
#90= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#91= IFCCARTESIANPOINT((-0.5,0.5,0.0));
#92= IFCPOLYLINE((#91,#90));
#93= IFCEDGECURVE(#36,#38,#92,.T.);
#94= IFCORIENTEDEDGE(*,*,#49,.T.);
#95= IFCORIENTEDEDGE(*,*,#61,.T.);
#96= IFCORIENTEDEDGE(*,*,#57,.T.);
#97= IFCORIENTEDEDGE(*,*,#53,.T.);
#98= IFCEDGELOOP((#94,#95,#96,#97));
#99= IFCFACEOUTERBOUND(#98,.T.);
#100= IFCPLANE(#101);
#101= IFCAXIS2PLACEMENT3D(#102,#103,#8);
#102= IFCCARTESIANPOINT((-0.5,-0.5,0.0));
#103= IFCDIRECTION((0.0,0.0,-1.0));
#104= IFCADVANCEDFACE((#99),#100,.T.);
#105= IFCORIENTEDEDGE(*,*,#65,.T.);
#106= IFCORIENTEDEDGE(*,*,#77,.T.);
#107= IFCORIENTEDEDGE(*,*,#73,.T.);
#108= IFCORIENTEDEDGE(*,*,#69,.T.);
#109= IFCEDGELOOP((#105,#106,#107,#108));
#110= IFCFACEOUTERBOUND(#109,.T.);
#111= IFCPLANE(#112);
#112= IFCAXIS2PLACEMENT3D(#113,#10,#114);
#113= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#114= IFCDIRECTION((-0.5,-0.8660254,0.0));
#115= IFCADVANCEDFACE((#110),#111,.T.);
#116= IFCORIENTEDEDGE(*,*,#93,.T.);
#117= IFCORIENTEDEDGE(*,*,#65,.T.);
#118= IFCORIENTEDEDGE(*,*,#81,.F.);
#119= IFCORIENTEDEDGE(*,*,#49,.T.);
#120= IFCEDGELOOP((#116,#117,#118,#119));
#121= IFCFACEOUTERBOUND(#120,.T.);
#122= IFCBSPLINESURFACEWITHKNOTS(3,1,((#123,#124),(#125,#126),(#127,#128),(#129,#130)),.UNSPECIFIED.,.F.,.F.,.U.,(4,4),(2,2),(0.0,1224.74487139159),(3.0,4.0),.UNSPECIFIED.);
#123= IFCCARTESIANPOINT((-0.5,0.5,0.0));
#124= IFCCARTESIANPOINT((-0.5,-0.5,0.0));
#125= IFCCARTESIANPOINT((-0.561004233964073,0.27232909936926,0.333333333333333));
#126= IFCCARTESIANPOINT((-0.27232909936926,-0.561004233964073,0.333333333333333));
#127= IFCCARTESIANPOINT((-0.622008467928146,0.0446581987385206,0.666666666666667));
#128= IFCCARTESIANPOINT((-0.0446581987385206,-0.622008467928146,0.666666666666667));
#129= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#130= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#131= IFCADVANCEDFACE((#121),#122,.F.);
#132= IFCORIENTEDEDGE(*,*,#53,.T.);
#133= IFCORIENTEDEDGE(*,*,#81,.T.);
#134= IFCORIENTEDEDGE(*,*,#77,.T.);
#135= IFCORIENTEDEDGE(*,*,#85,.F.);
#136= IFCEDGELOOP((#132,#133,#134,#135));
#137= IFCFACEOUTERBOUND(#136,.T.);
#138= IFCBSPLINESURFACEWITHKNOTS(3,1,((#139,#140),(#141,#142),(#143,#144),(#145,#146)),.UNSPECIFIED.,.F.,.F.,.U.,(4,4),(2,2),(0.0,1224.74487139159),(0.0,1.0),.UNSPECIFIED.);
#139= IFCCARTESIANPOINT((-0.5,-0.5,0.0));
#140= IFCCARTESIANPOINT((0.5,-0.5,0.0));
#141= IFCCARTESIANPOINT((-0.27232909936926,-0.561004233964073,0.333333333333333));
#142= IFCCARTESIANPOINT((0.561004233964073,-0.27232909936926,0.333333333333333));
#143= IFCCARTESIANPOINT((-0.0446581987385206,-0.622008467928146,0.666666666666667));
#144= IFCCARTESIANPOINT((0.622008467928146,-0.0446581987385206,0.666666666666667));
#145= IFCCARTESIANPOINT((0.183012701892219,-0.683012701892219,1.0));
#146= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#147= IFCADVANCEDFACE((#137),#138,.F.);
#148= IFCORIENTEDEDGE(*,*,#57,.T.);
#149= IFCORIENTEDEDGE(*,*,#85,.T.);
#150= IFCORIENTEDEDGE(*,*,#73,.T.);
#151= IFCORIENTEDEDGE(*,*,#89,.F.);
#152= IFCEDGELOOP((#148,#149,#150,#151));
#153= IFCFACEOUTERBOUND(#152,.T.);
#154= IFCBSPLINESURFACEWITHKNOTS(3,1,((#155,#156),(#157,#158),(#159,#160),(#161,#162)),.UNSPECIFIED.,.F.,.F.,.U.,(4,4),(2,2),(0.0,1224.74487139159),(1.0,2.0),.UNSPECIFIED.);
#155= IFCCARTESIANPOINT((0.5,-0.5,0.0));
#156= IFCCARTESIANPOINT((0.5,0.5,0.0));
#157= IFCCARTESIANPOINT((0.561004233964073,-0.27232909936926,0.333333333333333));
#158= IFCCARTESIANPOINT((0.27232909936926,0.561004233964073,0.333333333333333));
#159= IFCCARTESIANPOINT((0.622008467928146,-0.0446581987385206,0.666666666666667));
#160= IFCCARTESIANPOINT((0.0446581987385206,0.622008467928146,0.666666666666667));
#161= IFCCARTESIANPOINT((0.683012701892219,0.183012701892219,1.0));
#162= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#163= IFCADVANCEDFACE((#153),#154,.F.);
#164= IFCORIENTEDEDGE(*,*,#61,.T.);
#165= IFCORIENTEDEDGE(*,*,#89,.T.);
#166= IFCORIENTEDEDGE(*,*,#69,.T.);
#167= IFCORIENTEDEDGE(*,*,#93,.F.);
#168= IFCEDGELOOP((#164,#165,#166,#167));
#169= IFCFACEOUTERBOUND(#168,.T.);
#170= IFCBSPLINESURFACEWITHKNOTS(3,1,((#171,#172),(#173,#174),(#175,#176),(#177,#178)),.UNSPECIFIED.,.F.,.F.,.U.,(4,4),(2,2),(0.0,1224.74487139159),(2.0,3.0),.UNSPECIFIED.);
#171= IFCCARTESIANPOINT((0.5,0.5,0.0));
#172= IFCCARTESIANPOINT((-0.5,0.5,0.0));
#173= IFCCARTESIANPOINT((0.27232909936926,0.561004233964073,0.333333333333333));
#174= IFCCARTESIANPOINT((-0.561004233964073,0.27232909936926,0.333333333333333));
#175= IFCCARTESIANPOINT((0.0446581987385206,0.622008467928146,0.666666666666667));
#176= IFCCARTESIANPOINT((-0.622008467928146,0.0446581987385206,0.666666666666667));
#177= IFCCARTESIANPOINT((-0.183012701892219,0.683012701892219,1.0));
#178= IFCCARTESIANPOINT((-0.683012701892219,-0.183012701892219,1.0));
#179= IFCADVANCEDFACE((#169),#170,.F.);
#180= IFCADVANCEDBREP(#29);
#181= IFCBUILDINGELEMENTPROXY('1hMBdOkWj7WhC2kvgZp44F',#6,'BuildingElementProxy',$,$,#184,#182,$,.NOTDEFINED.);
#182= IFCPRODUCTDEFINITIONSHAPE($,$,(#183));
#183= IFCSHAPEREPRESENTATION(#15,'Body','AdvancedBrep',(#180));
#184= IFCLOCALPLACEMENT($,#11);
ENDSEC;

END-ISO-10303-21;


Edit on Github


Is this page difficult to understand? Let us know!