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How to deal with IsExternal property using Revit 2020

Entity inheritance

For example IfcWall objects – IsExternal property is as part of Pset_WallCommon

https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/pset/pset_wallcommon.htm

https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/schema/ifcsharedbldgelements/lexical/ifcwall.htm

Is External      Indication whether the element is designed for use in the exterior (TRUE) or not (FALSE). If (TRUE) it is an external element and faces the outside of the building.

Figure 1 Revit System Family Wall  – contains parameter Function – default that value ends up in Pset_WallCommon IsExternal.

Note 1: Revit has this built-in parameter only in: Wall, Floors, Stairs, Ramps and Doors categories.

Note 2: The IsExternal property applicable to (IFC4.3 version):

IfcBeam
IfcBeamType
IfcBuildingElementProxy
IfcBuildingElementProxyType
IfcChimney
IfcChimneyType
IfcColumn
IfcColumnType
IfcCovering
IfcCoveringType
IfcCurtainWall
IfcCurtainWallType
IfcDoor
IfcDoorType
IfcJunctionBox
IfcJunctionBoxType
IfcMember
IfcMemberType
IfcPlate
IfcPlateType
IfcRailing
IfcRailingType
IfcRamp
IfcRampType
IfcRoof
IfcRoofType
IfcShadingDevice
IfcShadingDeviceType
IfcSign
IfcSignType
IfcSlab
IfcSlabType
IfcSpatialElement
IfcSpatialElementType
IfcSpatialZone
IfcSpatialZoneType
IfcStair
IfcStairType
IfcWall
IfcWallType
IfcWindow
IfcWindowType
IfcZone

An easy way to find more information:  https://search.bsdd.buildingsmart.org/

Figure 2 Add the Shared parameter IsExternal to the projects, check the applicable Categories.
Figure 3 Fill the Parameter with correct value.
Figure 4 During IFC export – check the option “Export IFC common property sets
Figure 5 Result in IFC shown in Solibri Office.

Updated on July 29, 2022

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