The IFC for Revit addins that improve IFC import and export functionality are maintained at this GitHub site for versions newer than Revit 2018. In the past 2 weeks, updates have been release for all current Revit versions, and I have collected the direct links for you below. Note that the GitHub versions can be more up-to-date and current than the ones listed on the App Store.

If you want to check which version you currently have, you could use Start – Add or Remove Programs to do that without opening Revit:

checking Revit version in Add or Remove Programs
checking Revit version in Add or Remove Programs

If you are inside a Revit model, you can use File – Export – IFC and check the version in the dialog box header:

If you are looking for Revit 2018 and older versions of the IFC for Revit addins, check out the SourceForge site instead.

The update for Revit 2019 was particularly significant. Release notes copied below:


  • This version marks a significant milestone for IFC Exporter as it is now IFC4 Reference View certified (for Architectural Export and Structural Export Exchange Requirements)

New Features/Improvements:

  • Export of Area can now be assigned to IfcSpatialZone in addition to the default IfcSpace using IfcExportAs
  • Support exporting IfcGroup using ZoneGroupName parameter
  • Improved heuristic for assigning color to polygonal face sets
  • Improved handling to support for direct export of polygonal face geometry in IFC4
  • Support for IfcShapeAspect in other objects that have part geometries
  • Improved handling of Complex Property in the PropertySet definition
  • General improvements to support IFC4 based geo-referencing information with addition UI in export, and integration to the information found inside Revit file (usually comes from AutoCAD or Civil3D)
  • Reorganize the location for Exchange Requirement setting in the header of IFC File to be less hidden (now located right after the IFC version in export option UI)
  • Updates shared parameter definitions and Property set definitions based on the latest IFC4 ( specifications
  • Support allowing a predefined type for standard walls on export
  • General improvements dealing with objects with many holes
  • Added basic support to export Area as IfcSpatialZone entity

Bug Fixes:

Export bug fixes:

  • Fixed error during export for a specific object that became invalid in the export process with “Store the IFC GUID in an element after export” option
  • User defined property set can now be exported for IfcGeographiElement
  • Fixed export failure when ZoneClassificationName is set to Room for exporting IfcZone
  • Corrected GrossVolume quantity information with the correct unit
  • Fixed exporting issue for a Ceiling containing Arc geometry
  • Fixed issue with duplicate steel connection geometries or missing connection
  • Fixed issue with IFC export – steel connection steel connection elements missing or wrongly exported
  • Fixed issue on missing ceiling geometries in IFC4 RV export mode
  • Fixed issue on objects with Parts that is below the first (lowest) level
  • Fixed issue with export Roof in some cases
  • Fixed crash issue if the “Rasters” are set to be exported to “IFCGrid”
  • Fixed issue with IFC option “export links as separate models” causes wrong object placement
  • Improved export Parts functionality
  • Fixed issue that IFC Version doesn’t update when changing the “In-Session setup”
  • Fixed IsExternal calculation on element types to correctly determine value
  • New shared parameter assigned to Curtain walls is now exported when exporting from Revit to Navisworks
  • Update category mapping to deal with IfcSpaceTypes and IfcOpeningTypes
  • Fixed issue with incorrect slab thickness when Opening IFC in Revit
  • Fixed some issues on export with different coordinate base
  • Fixed some issues on exporting Wall elements
  • Improved handling reserved Windows name
  • Export HVAC_HEAT_GAIN with current units (Watts)
  • Removed duplicate base quantity NetSideArea exported for walls
  • Improved export with the Property Set option “Export schedules as property sets”
  • Fixed issue with IFC4 Reference view, which fails for some models from Factory Live
  • Update the CSIORG link in the IFC exporter
  • Changed IfcGeometricRepresentationContext from “Annotation” to “Plan”
  • ClassificationCode(2) is now processed during export even if ClassificationCode is missing
  • Corrected Area quantity property of doors
  • Improved Materials export, that works for some floors but not others of the same type
  • Fixed issue with wrong Base Quantity information in some scenarios in IFC export 2×3 Coordination View
  • Fixed issues with warnings are shown when exporting to IFC4RV in some models
  • Improved Railings import to Revit via IFC
  • Properly convert this Flow_Rate parameter on Export
  • Corrected 2D CurtainWall door swing on IFC Export
  • Nested curtain wall element now will get proper parameters while export to IFC
  • IFC-Export configuration will now remember the previous settings including: “Project Origin/Coordinate Base”
  • Improved exporting of Material parameter
  • Improved IFC4 RV Exchange Requirement, which may be missing when File Header is not initialized
  • Support allowing a predefined type for standard railings on export
  • Fixed IFC4 “opening as recess” code for ReinforcingMesh case
  • Fixed issue with IFC export where some geometries are exported slightly longer extrusion
  • Fixed issue with IfcGeographicElement not exporting user-defined PropertySets

Import bug fixes:

  • Improved Rebar import
  • Improved import of Windows that are not cutting a wall in a linked or opened IFC
  • Recognize the angle between Project North and Survey Point properly in Revit IFC import/link
  • Improved import of Columns that may be placed in the wrong location on IFC Link in some cases
  • Improved import of beam cover
  • Fixed issue with Certain Tekla IFC geometry not visible when using Link IFC
  • Improved link IFC that may have incorrect geometry imported for some cases
  • Improved Link IFC file in Revit that in some cases failed with the model empty and an error appears in log file
  • Fixed issue with translation IFC having mm units using Revit IFC loader makes default model view small unexpectedly on LMV
  • Fixed issue related to invalid/corrupt IFC files that “load” without any errors
  • Improved link IFC file properly inside Revit 2020
  • Grids placed by IFCOFFSETCURVE2D will be placed at open IFC in the correct unit
  • Fixed issue with multiple versions of the same IFC file get loaded into Revit Cloud Worksharing Host resulting in duplicate geometry
  • Improve the structure in Link IFC that may end up upside down
  • Fixed missing material information upon import IFC
  • Recreate IFC/Import_Quantities/Import_Quantities.txt
  • Support IfcGridPlacement for Link IFC
  • Avoid duplicate instance and type names when linking in an IFC file
  • Improved creation of Geometry which may be missing for some IFC models
  • Fixed issue for some IFC files that failed to show in BIM 360 viewer
  • IFC link – model is now correctly positioned when there is rotation component in IFCSite local placement
  • Improved issue due to “bad” data involving Wall with zero thickness inside the IFC file that caused differences between IFC from Allplan opened/imported vs linked in Revit
  • Improved handling of detailed geometry containing IfcAdvancedBrep in REVIT 2020 and 2021
  • Improved slab elements import which may be missing in some IFC file
  • Corrected IfcPort ConnectedTo IfcGUID information that contained its own GUID instead of the GUID of its connected Port

Known Issues/additional notes:

  • This release still contains issue that Steel Connections may not be exported correctly
  • Export configuration “IFC2x2 ePlan Check” has been removed as it is already obsolete. If there is any saved configuration, the option will be automatically assign to IFC2x3 as default

As software and standards mature and even become archaic, they inevitably attract baggage along the way. Years of technical debt amassed by well-intentioned developers and product managers will be paid for by us and our children.

This is particularly evident when we start talking about the Id of Revit elements, and the IFC GUID syntax. As most of you are aware, Revit carries a number of different identifying attributes for each and every element. Here is a basic list:

  • Element Id – the numerical form of a Revit Id, you can interact directly with this using the Select By Id command in Revit
  • UniqueId – “A stable unique identifier for an element within the document.” This is not a correctly formed UUID, but rather a concatenation of a standard UUID for the Revit EpisodeId (session based), along with the Revit element Id. From Jeremy’s post: similar to the standard GUID format, but has 8 additional characters at the end. These 8 additional hexadecimal characters are large enough to store 4 bytes or a 32 bit number, which is exactly the size of a Revit element id.
  • DwfGuid (Export Guid) – this is a correctly formed UUID in .NET / standard format
  • IfcGuid – identical to DwfGuid, but encoded differently according to IFC rules created in the mid-90s. At the time, it was deemed worthwhile to ‘compress’ the IFC Guid to the shorter form we still have to deal with today.

It would be nice if Revit and IFC shared a single common unique identifying syntax, but unfortunately this is not the case.

The above Ids do actually bear some predictable relationship to each other. The UniqueId is formed by Revit joining the EpisodeId and the encoded Element Id, the Dwf or Export Guid is created by an algorithm that has a number of conditional rules, and the Dwf Guid can be converted to the backwards-compatible IfcGuid format through a different algorithm, originally created in C. Those algorithms can be sourced in various places (see links in Further Reading below).

Also, some of these get exposed in different ways – if you create Element-bound BCF files, they will typically show the IFC Guid syntax. Further, if you export an IFC file from Revit and tick the option on the Exporter, it will write the IfcGuid to a parameter on the element.

You can query the Element Id directly in Revit (Modify ribbon, Inquiry panel, IDs of Selection):

However, for the purpose of this post, let’s assume you are using Dynamo with IronPython, and you want to query all 4 Ids from an element.

We at least need to import the Revit API and the Revit IFC API:

import Autodesk 
from Autodesk.Revit.DB import *
from Autodesk.Revit.DB.IFC import *


Following this, we can use the various Dynamo and Python commands to access the Ids:

elementIds, uniqueIds, DwfGuids, IfcGuids, successlist = [], [], [], [], []
for i in e:
        DwfGuids.append(ExportUtils.GetExportId(doc, ElementId(i.Id)))
        IfcGuids.append(ExporterIFCUtils.CreateSubElementGUID (UnwrapElement(i),0))
OUT = elementIds, uniqueIds, DwfGuids, IfcGuids, successlist


Notice the commands and properties used:

  • Element Id – query the Element.Id member
  • Unique Id – query the Element.UniqueId member
  • Dwf or Export Guid – use the ExportUtils.GetExportId method
  • IfcGuid – use the ExporterIFCUtils.CreateSubElementGUID method (index 0 refers to the main element itself)


From here, I create a Dynamo node that eats Revit elements and gives us back these Id values:

before node created


After “All The Ids” node created


This node will be published in the Bakery package on the package manager, and to Github.


Further, our VirtualBuiltApp platform has been developed to store and query multiple Ids for a single element.


Example output from the Dynamo / Python (initial test showed the Dwf Guid is still a .NET object, that probably should get converted to a string for consistency).

[<System.Guid object at 0x0000000000000071 [c98618bf-7112-4e90-8a71-8ab768f2b8b8]>]


I added str() to the Python:


Final test showing the 4 different Id values for a single object:



Further reading:

Its good to see that IFC for Revit development is continuing… This post shows how you can download and install the new version, along with detail on what has been updated in this version.


Download and run MSI, you can use this link to Direct Download IFC v19.2.0.0 from GitHub

Checking your Version:

In Revit, go to:

  • File menu
  • Export ->
  • IFC
  • Look at the top of the dialog box, it should say “Export IFC (v.

Here is a list of fixes from the Release Notes:

• This is generally a bug fix release with some new IFC functionality.

New Export Functionality:
• IFC Exporter now supports IFC Spatial Container assignment override using IfcSpatialContainer parameter. Valid values are: “IFCSITE”, “IFCBUILDING”, or name of the Building Storey
• Improved detection of Door operation type using the 2D swing symbol (arc). The improved version detects range of angles (not limited to 90, 180 or 360 degrees only)
• Added support for IfcCivilElement
• Replace IfcRelConnectsPortToElement with IfcRelNests for IFC4 export as recommended in IFC4 specifications, allowing non-IfcDIstributionElement to participates in the connectivity
• Added support for RampFlight and Run from generic models or family representing more complex Ramp for export to IfcRamp and IfcRampFlight
• Added various property Calculators
• Improve performance when exporting a large mesh
• Enable IFC Property Templates
• Allow multiple Property Template mapping from txt
• Projection improvement
• Enable site and project property creation
• Utilize Site GlobalId method
• Add multilanguage support files for German language (DE)
• Provide a complete list of all Shared Parameters used by Revit on export including ALL properties defined in IFC PropertySet Definition for both Instances and Types. The lists are included in the installer and will be placed in the install folder: IFC Shared Parameters-RevitIFCBuiltIn_ALL.txt (for the Instance parameters) and IFC Shared Parameters-RevitIFCBuiltIn-Type_ALL.txt (for the Type parameters).
• Improve consistency for setting the object direct attributes, support IfcObjectType[Type] special parameter to drive instance ObjectType parameter from the Type, update the shared parameter definition files (now for [Type] parameters we will also maintain the GUID as long as it remains)
• Incremental work towards IFC4RV 1.2 MVD

Export Bug Fixes:
• Consistent ExportAs entity and its PredefinedTypes
• Export fails when there is no associated Plan View to a level
• Additional fix for error getting 2D data when there is no Level associated to the FamilyInstance
• Various fixes related to missing geometry and export failures
• Fixed performance issue in IFC2x3 export due to error in creating types
• Fixed issue with slanted Pile
• Fixed issue related to element that is split into parts
• Improvement in handling level of Part Override
• Some improvements on classification (issue #31)
• Improve voiding of IfcMappedItem representation (issue #9)
• Fixed issue on Composite curve tolerance (issue #5)
• Fixed issue where element is still exported even though it is set to not-exported in the mapping table
• Bugfix for incorrect cylindrical hollow core Beam export in IFC4RV
• Fixed for issue #51
• Bugfix based on Pull request #52 for MEP connector, and a few clean-ups
• Fixed minor issue to ensure generic element exporter will generate consistent GUID for the instance
• Fixed issue when OverrideElementContainment is used but the Site does not have site geometry (from Topography surface)
• Add support of OverrideElementContainment also for SpatialElement (Room/Space/Area). This enables export to place IfcSpace directly to IfcSite for example, which is useful for outdoor spaces
• Refactored the handling of valid entity and type and fixed a few defects related to it (Github issue #68)
• Fixed issue with Stair Landing that is offset far away from the supposed location
• Fixed issue with missing geometry when assigning IfcExportAs to the Spatial Element (Issue #23) However, in IFC4RV or DTV, there is a fixed list of valid entities that will be enforced, entity such as IfcExternalSpatialElement will be exported as IfcBuildingElementProxy.
• Fixed performance issue when there is a large triangulated geometry for export to IFC4RV
• Fixed issue of exception raised during export when “Export schedules as property sets” option is selected, and the model contains ViewSchedule from the template
• Update Source/IFCExporterUIOverride/IFCExporterUIWindow.xaml.cs (issue #59)
• IFCBooleanOperator.Union don’t work! (issue #32)
• Fixed issue in exporting IfcBuildingElementProxy that assigns an invalid enumeration for CompositionType in Ifc2x3 export
• Fixed issue related to opening that cuts through multiple walls (note that this is not yet 100%. In some cases, due to the extended body of the opening (that is defined in the native code) there may be more cut than it should for a few cases
• Fixed issue with changing GUID of Window or Door when it is in the context of the opening that cuts multiple walls (issue “IFC Guid on family” in SourceForge)
• Fixed IfcWindowLiningProperties, IfcWindowPanelProperties GUID issue
• Improve handling for multiple meshes in a tessellated geometry that causes missing some surface body.
• Fixed issues of UserDefined propertysets that fails to recognize the Pset assigned to a Type. Also improve the handling for Conditional Pset (by PredefinedType)
• Fixed regression issue #70 missing toprail for IfcRailing on export
• Fixed issue with “runaway” flex duct with “Keep Tessellated Geometry as Triangulation” option selected (issue #58)
• Fixed regression issue (issue #96) IfcZone ObjectType not exported
• Fixed issue of Naming override/default value, and issue of Qto_ properties are not exported
• Fixed issue on a wrong enumeration for the SweptArea (it was set to .CURVE., should be .AREA.)
• Fixed for orphaned entities and wrong footprint information due to incorrect projection direction for IFC4RV requirements. IFC4RV Beam (Arch) is now without error in the automated test
• 1st fixed for issue related to runaway parts in “export only elements visible in view” (there are still situations that may cause a wrong rotation, but the test case reported in issue #86 so far looks good)

Import Bug Fixes:
• Improve voiding of IfcMappedItem representation (#9)


I have posted about BIMserver a few times before, including how to setup and run your own IFC web server. It seems that BIMserver and IFCWebserver are actually different but similar things (see this page). There is a publicly accessible instance of IFC Web Server over at this link.

The hosted version seems to be a bit of tech demonstration rather than a full production tool? Here is a link to the GitHub repos as well.

To test it out, you can take these basic steps:

  1. Create a user account and login
  2. Upload an IFC file (I tried a 20mb file which took quite a while)
  3. Wait for processing
  4. View and work with your file

Here is a look at the basic interface:

It offers a few interesting functions, including the ability to browse the data as a tree:


From the website:

IFC WebServer is a data model server and online viewer for Building Information Models (BIM) based on IFC standards.

It aims to simplify sharing and exchanging of information from BIM models using open and standard formats like (IFC, HTML, XML, CSV, JSON) and check the quality of BIM models (Level of Details, Level of Development). BIM managers and designers can query, filter and make reports about any information inside IFC models easily.

The project consists mainly of two parts:

(1) Data model server IFCWebServer

IFCWebServer enable 100% access to all information and relations inside IFC models. It supports  all IFC official release starting with IFC2X_Final issued on 2001 to the latest release IFC4 Add 2 release issued on July 2016. Moreover, it supports any valid IFC sub schema or extended schema so it can be used by researchers and IFC developers .

The IFCWebServer can be used also in universities as an easy to use portal within BIM courses. Students can register and upload IFC models, explore the models structure, apply filters, create sub-models, generate reports, study the IFC data model and compare IFC official releases.

(2) Online BIMViewer

Despite of having easy access to the information in BIM models as the main interest (through queries, filters, scripts and reports), the online 3D visualization offered by BIMViewer provide an handy way to view, share BIM models and visualize the results of data queries online inside the web browser.

The excellent and open-source IFC extension for Revit (previously known as IFC Exporter) has been updated. Please see below for download links and update details.

Download links:
16.6 for Revit 2016

17.3 for Revit 2017

Readme details for the latest release:


– Minor improvements to the Importer class to make it easier for developers to create a custom Importer.
– We now support the IFC4 Addendum 2 schema.  Specific improvements based on that will be listed below.  For this update, you will have to manually add the IFC4_Add2.exp file (included with this package), to the EDM subfolder of your Revit Program folder.  We will automate this in a future update.

New Export Functionality:

– Allow overriding material names on export by using IfcName shared parameter.
– Expand the use of types for many elements that didn’t export types before, including beams (IfcBeamType), curtain walls (IfcCurtainWallType, and types for mullions and panels), and footings (IfcFootingType).
– Improved ability to export some geometry as IfcSweptSolid.
– Try to use axis information, if it exists, when exporting beams and members in addition to columns.
– (IFC4) Better support beam, column, and member base quantities, including weight.
– (IFC4) Collect material information for profiles for beams and columns.
– (IFC4) Expand use of FootPrint representations to columns and slabs.
– (IFC4) Expand use of IfcMaterialLayerSetUsage if the entity has a compound structure in Revit, as allowed by IFC.
– (IFC4) No longer create StandardCase IFC entities, as these have been deprecated (including IfcWallStandardCase).
– (IFC4) Support IfcMaterialConstituent and IfcMaterialProfileSet for a number of elements.
– (IFC4) Use Built-in parameter “Structural_Bend_Dir_Angle” to get “Roll” property for PSet_BeamCommon and PSet_ColumnCommon.
– (IFCAdd2) Support IfcPolygonalFaceSet.

Export Bug Fixes:
– Allow exporting to IFC while using Collaboration for Revit where the default directory isn’t local.
– Better support for MEP type entities, that didn’t always export correctly.
– Correct the parameters of the directrix of some IfcSweptSolids.
– Fix correct mapping of IfcBurnerType/IfcGasTerminalType and IfcElectricHeaterType/IfcSpaceHeaterType.
– Fix creation of types for sub-entities of IfcDistributionControlElement.
– Fix offset problem when using the “Export Linked Files as Separate IFCs” option in locales where the decimal mark is not a point.
– (IFC4) Correct names of IFC4 entity quantity sets.
– (IFC4) Fix the name of IfcCommunicationsApplianceType.

New Import Functionality:

– Add support for IfcDerivedProfileDef.
– Support IfcRelClassification.
– (IFC4) Support IfcMaterialProfile, IfcMaterialProfileSet, and IfcMaterialProfileSetUsage.
– (IFC4) Support IfcMaterialConstituent and IfcMaterialConstituentSet.
– (IFC4) Support IfcTessellatedFaceSet and IfcPolygonalFaceSet.
– (IFC4) Improve mapping from Roll parameter to structural bend direction angle.
– (API only) Allow for two new options, CreateDuplicateZoneGeometry and CreateDuplicateContainerGeometry, that disable the duplication of geometry for zone elements and containers, respectively.

Import Bug Fixes:
– Better reporting when importing an IFC file with invalid rectangular or circular profiles (e.g., a 0 radius profile).
– Don’t show the void geometry when subtracting a void from an empty solid as a result of an IfcBooleanResult calculation.
– Ensure that IFC2x schema files can still be imported.
– Fix import of some IfcSurfaceCurveSweptAreaSolids.

When Revit exports to IFC, it typically uses the current Location (Survey Point) Shared Coordinates as Origin. You can observe this in the IFC file:


But what if you want to Export to IFC with Project coordinates (Revit origin), not Shared?

We want to do this because we have set up the import process from Tekla using this same Revit origin, here and particularly this:


1) Firstly, make a container RVT file with one Site Location, no shared coordinates. In other words, Project Base Point, Survey Point, and Revit Origin are all in one place.


2) Then, open the project you want to export, and link this ‘container’ file Origin-to-Origin

3) Transfer Project Standards:


4) Choose the Link you made, and Project Info (only):


5) Choose New Only (this will just bring in the uniquely named project location from the link):


6) Open Location dialog in Revit, under Site you will notice a new “Site“. Set it current with the Make Current button:


7) Now that the Project Origin (neutral coordinates) are set, you can export to IFC:


8) After Exporting, reset the coordinates back to what it was before with Make Current:


9) Optional: delete the IFC Export site definition if you don’t need it anymore…

I previously posted about a similar method, but it was a bit ‘destructive’, whereas the above process can be implemented into a live project more easily:
What Revit Wants: When and how to neutralize Survey coordinates for IFC export from Revit

Further reading:

Ever wondered how to install and use BIMserver to create your own IFC web viewer?

Sometimes I finish a blog post and think, what a mess…

That’s because I often sketch out things as I do them, on the fly. And so you end up with essentially a collection of notes. In any case, here are my notes on how I got BIMserver up and running on my workstation, so that I can view, merge and work with IFC files locally. I hope you can understand the fragments of thought below 🙂

The bimserver Java module will be limited by the Java version on your system. So, if you want to be able use big memory, you should be running a 64 bit Java engine.

Install JDK for 64 bit windows, such as from here:

Windows x64 187.31 MB jdk-8u77-windows-x64.exe

Download and Installation
Release 1.4.0-FINAL-2015-11-04 · opensourceBIM/BIMserver


Put the bimserver jar file in some logical place on your computer, it will create subfolders here.

Important Note! I discovered that bimserver doesn’t play nicely with file paths that have a whitespace character, so use underscores if you have to

Start by double clicking the JAR file – bimserver-1.4.0-FINAL-2015-11-04.jar

Then, tweak settings to your liking. Here are mine:


Click Start

Allow the BIMserver engine to initialize itself for a few moments, it will create a bunch of folders.

Once its ready, you might have to give it access through Windows Firewall


Click Launch Webbrowser, then fill out the login details:


Once logged in to the client in the browser, use Project – New Project, and give it a name.

You now have a space where you can upload, merge, view, query and validate IFC files.

To Merge IFC Files

  1. Add ‘sub projects’ for each IFC you want to merge
  2. Checkin a model to each subproject
  3. You can now view the 3D merged IFC model in your web browser by clicking on the top level ‘eye’ symbol and wait for Loading to complete
  4. Also, you can download the top level ‘merged’ project as a single IFC



To test your merged model, you can immediately create a New Project and Checkin your merged model.

Further notes
You can now create multi-tasked IFC geometry tasks, which look like this:


Sometimes they use lots of memory!


Keep in mind that this is essentially a web application. The ‘next level’ would be to set this up to run on your company webserver to share IFC models internally or to everyone via the cloud.

The source for the web viewer is here:
opensourceBIM/ Javascript client for Building Information Modelling, using open standards like IFC, BCF and BIMSie. Using Bootstrap, BIM Surfer, etc..

This video may be of interest:

IFC for Revit 2015 (v15.7):

IFC for Revit 2016 (v16.4):

New Export Functionality:
Append “(Type)” to all internal Revit type property sets, to avoid having multiple property sets with the same name assigned to the same IFC entity.
Changed how the classification code is parsed so that classifications can have brackets and colons in them.
“Extra Low” level of detail now applies to all faceted BRep geometry, allowing many more files to export without hitting the size limit.
If a userdefined property set contains the same property name more than once, take the last nonempty value (don’t duplicate the property name).
Rebar elements can generate up to 1024 consistent GUIDs for individual IfcReinforcementBars, up from 256.
(IFC4) Zones can now have a long name, set by the “ZoneLongName” shared parameter for nonMEP zones, and the “IfcLongName” parameter for MEP zones.

Export Bug Fixes:
Don’t create orphaned IfcStyledItems.
Don’t export invisible geometry in beams.
Export DirectShapes of Walls category.
Export elements with empty custom classification field values.
Floors exported as IfcSlabs correctly report if they are load bearing or not, using either the “LoadBearing” shared parameter or the Structural builtin parameter, in that order.
Improve performance in certain cases where we can’t create a valid tessellation for a face.
The “Use active view to generate geometry” option now works correctly.
(IFC4) Correct the orientation of some IfcAdvancedBRep faces.

New Import Functionality:
Import IfcProxy as Generic Models.

Import Bug Fixes:
Fix how the IFC GUID is set for certain elements.
Fix the orientation of some imported objects where part of the local placement needs to be calculated.
(IFC4) Read in some missing relations caused by “IsDefinedBy” split into 3 inverse attributes.

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