CV-2x3-157 (aka CV-06-157)

Agreement on a particular type of building element proxy to exchange provisions for voids

Based on          IFC2x3

Initiator            ISG Meeting-Berlin

Effects              Extended Coordination View

Date                    2008 10 23

Description:

The agreement defined a work around to exchanging proposals for openings that are to be coordinated between HVAC and architectural/structural design applications. Such "proposals for openings" - or provisions for voids are 3D bodies that indicated the required void for building service flow segments. The voids are not yet subtractions of the building element (wall, slab), but placeholders, that have to be converted into "real" openings by the architect or structural designer.

It reflects a very common and highly important coordination task that should be supported by the coordination view.

The agreement includes:

any provision for void element should be exchanged as IfcBuildingElementProxy with ObjectType = 'ProvisionForVoid'. It refers to a property set with Name = 'Pset_ProvisionForVoid'. The property set has the following properties defined:

    * Width : "The width (horizontal extension in elevation) of the provision for void, only provided if the Shape property is set to "rectangle" - IfcLengthMeasure

    * Height : "The height (vertical extension in elevation) of the provision for void", only provided if the Shape property is set to "rectangle" - IfcLengthMeasure

    * Diameter : "The diameter (in elevation) of the provision for void, only provided if the Shape property is set to "round" - IfcLengthMeasure

    * Depth : "The depth or thickness of the provision for void" - IfcLengthMeasure

    * Shape : "The shape form of the provision for void, the minimum set of agreed values includes 'Rectangle', 'Round', and 'Undefined' "- IfcLabel

    * System : "The building service system that requires the provision for voids, e.g. 'Air Conditioning', 'Plumbing', 'Electro', etc." - IfcLabel

A sample ifc file would include:

   #33=IFCBUILDINGELEMENTPROXY('2JlkZSa_vF3xOXqR_OrxWi',#5,'any name','any description','ProvisionForVoid',#36,#111,$,.ELEMENT.);

   #37=IFCRELDEFINESBYPROPERTIES('3DibaTRPH5NhSyVCFz19Aj',#5,'',$,(#33),#38);

   #38=IFCPROPERTYSET('3nTXJcSDf55e44yDrj6mHj',#5,'Pset_ProvisionForVoid',$,(#44,#45,#46,#47,#48));

   #44=IFCPROPERTYSINGLEVALUE('System',$,IFCLABEL('Waste Water System'),$);

   #45=IFCPROPERTYSINGLEVALUE('Shape',$,IFCLABEL('Rectangular'),$);

   #46=IFCPROPERTYSINGLEVALUE('Width',$,IFCLENGTHMEASURE(300.0000),$);

   #47=IFCPROPERTYSINGLEVALUE('Height',$,IFCLENGTHMEASURE(300.0000),$);

   #48=IFCPROPERTYSINGLEVALUE('Depth',$,IFCLENGTHMEASURE(524.0000),$);

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