IFC import and export in BricsCAD

About IFC

The Industry Foundation Classes (IFC) data model is designed to describe building and construction industry information. IFC is a platform-neutral, open-format file type. IFC provides interoperability between different BIM software platforms.

BricsCAD BIM supports IFC2x3 and IFC4 for import and export. The IFC2x3 and IFC4 property namespaces are merged into IFC namespace. Differences between the two schemas will be dealt with in the background during IFC Import or Export. The IFC standard includes both parametric and non-parametric shapes, material definitions, metadata in the BIM file, and property sets (PSets).

When you export an IFC file from BricsCAD, the properties will be exported as IfcPropertySet. These property sets contain common IFC properties. User-defined property sets can also be exported.

Note:
  • BricsCAD BIM created IFC files can be used in different coordination workflows with many tools (for example, Solibri).
  • Some software allow for editing only IFC files created with specific Authoring Tools, while actively blocking files created with other tools. Other uses of BricsCAD BIM created IFC files on these software are possible (for example, viewing).
  • When IFCEXPORTIDSPROPERTIESONLY system variable is ON, only the IFC and custom properties of the active namespace (selected in the drop-down menu) specified in the imported ISD file are exported.
  • BricsCAD BIM also supports exporting files in RVT format (only for viewing).

Mechanical system layouts, structural models, and architectural models that are exported from different IFC compliant software applications can be imported into BricsCAD BIM.

IFC2x3 vs IFC4
IFC4 is an advanced schema of IFC2x3. It is extended and overcomes certain limitations of IFC2x3. There are geometric and data improvements as well as new and changed Model View Definitions. Geometric improvements include more parametric support, more efficient handling of meshes and an improved way to add textures, lighting settings, etc. An increased number of property sets, make the IFC data model more complete and more granular. For IFC4 the coordination view has been replaced by two official Model View Definitions: the IFC4 reference view and the IFC4 Design Transfer View. Anyway, differences between the two schemas will be dealt with in the background during IFC Import or Export and the IFC2x3 and IFC4 property namespaces are merged into IFC namespace.

IFC import and export settings

The IFC import and export settings are set in the Settings dialog box:

Variable Description
IfcImportSettingsConfig

Specifies the name of the IFC import settings configuration file.
IfcExportBaseQuantities

Enables/disables exports derived from base quantities of BIM elements.

If this setting is enabled, calculated quantities (e.g. length, thickness, height) for each BIM element will be exported to IFC.
IfcExportElementsOnOffAndFrozenLayers

Enables/disables the export of BIM elements that are in Off and Frozen layers.

By default, this setting is enabled.
IfcExplodeExternalReferences

Enables/disables exploded external references in IFC spatial structures.

If this setting is enabled, each external reference will be divided into the elements (e.g. IfcSite or IfcBuilding) based on the project spatial structure.

Important: Use the BIMCLASSIFY command to Classify Xrefs as BIM XReferences prior to doing an export with this setting enabled. Otherwise, the result will be a block per Xref.
IfcTesselateBSplineCurvesAndSurfaces Controls whether BSpline curves and surfaces are tessellated.
IfcExportSweptSolidsAsBRep Allows to export all extrusions, revolutions, swept 3D solids with clippings and subtractions using a boundary representation (BRep).
IfcExportProfileCenterOfGravity

Only for IFC2x3.

Exporting the center of gravity may cause a wrong positioning of linear solids in certain IFC viewers.

The center of gravity is never exported to IFC4 or higher.
IfcExportMappingPath Allows to specify an export mapping file path. See Import/Export mapping of IFC files.
IfcExportMultiPlyElementsAsAggregated

Enables/disables the export of building elements with multi-ply compositions as aggregated entities.

If this setting is enabled, each ply material belonging to a building element (e.g. wall or column) is calculated and exported individually.

This setting can be used to export quantities and value definitions for Ply-elements.
IfcExportTessalation

Controls the level of tessellation of the exported geometry.

If the 'Current' faceting option is chosen, the faceting as set by FacetRes or Modeler properties is used.

Choosing the Low, Medium or High options of regeneration of the facets. This makes the process longer.
IfcCreateUniqueGuid Defines whether a unique GUID for nested elements should be generated upon export.

1: unique guids for inside classified blocks

2: inside classified Xrefs

3: to enable both inside classified blocks and Xrefs
IfcExportAuthor Enables/Disables the export of the author name in the IFC file header.
IfcExportOrganization Enables/Disables the export of the organization name in the IFC file header.
IfcExportAuthorization Enables/Disables the export of the authorization information in the IFC file header.
IfcExportIDSPropertiesOnly When an IDS-XML file has been imported, this setting controls whether only the properties required by the IDS should be exported in the IFC file or all properties should be exported.

Off (0): Export all properties

On (1): Export only the properties required by the IDS
IfcExportValidateModel Checks that an IFC model complies with schema rules during IFC export. Problems are reported in an export log next to IFC file.
Warning: Validation takes extra time and can slow down the export of big IFC files.

Off (0): Does not apply IFC model validation

On (1): Applies IFC model validation

Import an IFC file in BricsCAD

  1. To import an IFC file into your project, type Import in the Command line. The import file dialog box displays.
  2. Select the IFC file format (1) from the Files Of Type drop-down list and choose the IFC model you want to import.
  3. Click Open to import the IFC model.
    Note: All IFC2x3, IFC4 and IFC4x1 files can be imported, but all are merged into a single IFC namespace. Differences between these schemas will be dealt with in the background during IFC Import. When the IFC file is imported the data from the imported file integrates with the BricsCAD data structure which means you can work with them right away. If the imported data contains custom properties, these property sets will be made available.

    You can create custom property sets and properties directly in BricsCAD BIM and associate them with imported entities.

  4. (Optional) Change the IFC import settings using the BIM section in the Settings dialog box. See Change IFC import and export settings.

Export an IFC file in BricsCAD

  1. To export an IFC file in your project, click the BricsCAD icon, select Export and then Export to IFC. Select the Entire model option. The IFC file name dialog box displays.
  2. Select the desired IFC file format in the Save as type list and save the IFC model. The options are IFC2x3, IFC4, and IFC4x1.
  3. Click Save to export the IFC model.

    The exported BIM model is saved as an IFC2X3, IFC4, IFC4 Reference View file, or IFC4x1 file and it is now ready to use in any IFC certified application.

  4. (Optional) Change the IFC export settings using the BIM section in the Settings dialog box.

Export an IFC file only for selected entities

  1. To export IFC model partially in your project, type IFCEXPORT in the command line or press the Export to IFC icon in the Home Toolbar.

    You are prompted: Select entities to export [Entire model/selection options (?)] <Entire model>:

  2. Select the entities in your model space to export as IFC and press Enter.

    The IFC file name dialog box displays.

  3. Enter a name for the IFC file, choose the IFC format for export (IFC2x3, IFC4, IFC4 Reference View file, or IFC4x1) and click the Save button. The selected entities are exported to IFC.

Import an IFC Project as Xrefs

  1. Go to Settings (type SETTINGS in the Command line or go to Settings in the ribbon > Settings).
  2. Navigate to BIM > Import and Export > IFC.
  3. Check Import IFC project structure as xrefs box (4).
  4. Type IMPORT in the Command line. Specify which IFC file you want to open and click Open.

    The drawing will now open with Xrefs made for each floor in each building. This allows you to easily split large files into smaller BricsCAD files.

Export a BricsCAD BIM Project with Xrefs exploded

  1. Use the BIMCLASSIFY command to Classify Xrefs as BIM XReferences.
    Important: If you don't go through this step, your Xrefs will be exported as blocks, instead of separate entities that are part of the Xref.
  2. Launch the SETTINGS command to open the Settings dialog box.
  3. Go to BIM > Import and Export > IFC.
  4. Check Explode external references in IFC spatial structure (5).
  5. Click the BricsCAD icon and then select Export. Choose IFC2x3 or IFC4, specify the name of the exported drawing and click Save. The exported drawing will now have all Xref elements merged onto one Site and one Building.

Work with IFC properties

  1. Open the BIM Properties dialog box using one of these methods:
    • In the ribbon go to Home > Classify > Spatial Locations > Properties (6). The BIM Properties displays.
    • In the Command line, type BIMPROPERTIES.
  2. Select IFC in the Namespace drop-down menu (7).
  3. Search for the desired property in the properties list (8).
  4. Set Visible (9) to Yes for the section to be visible in the Properties panel. Set to No to hide the section.
  5. In Categories select the IFC Classes you wish to display (10).
  6. Once all properties have been set, click OK.
  7. Select an object of the type/category that you just enabled the Property Set for (in this example an Energy Conversion Device). Go to the Properties panel. Scroll down to the section of properties you just enabled.
  8. Fill in the data as required (11).
Note: IFC properties for spatial elements can also be added through the Properties panel.

Profiles in IFC import

When importing profiles from an IFC file to BricsCAD, you can either import the profile properties in the IFC file, or let BricsCAD look for corresponding profiles in the Project and Central Database, based on the geometry. The profiles will then be assigned with proper Profile Standard, Profile Name and Profile Size in the Properties panel (12).

Supported IFC Classes

Following IFC Classes are supported by BricsCAD BIM. These are the same categories as the classify options in the BIMCLASSIFY command.

IFC Classes that are backward compatible with older BricsCAD versions:

IfcWall

IfcBeam

IfcColumn

IfcSlab

IfcStair

IfcStairFlight

IfcRamp

IfcRampFlight

IfcRailing

IfcCurtainWall

IfcRoof

IfcBuildingElement

IfcSite

IfcBIMXreference

IfcGridAxis

IfcGrid

IfcAnnotation

IfcWindow

IfcDoor

IfcCovering

IfcFurnishingElement

IfcOpening

IfcDistributionControlElement

IfcDistributionPort

IfcDistributionFlowElement

IfcDistributionChamberElement

IfcEnergyConversionDevice

IfcFlowFitting

IfcFlowController

IfcFlowMovingDevice

IfcFlowSegment

IfcFlowStorageDevice

IfcFlowTerminal

IfcFlowTreatmentDevice

IfcFlowConnectionPoint

IfcMember

IfcFooting

IfcPile

IfcReinforcingBar

IfcReinforcingMesh

IfcTendon

IfcTendonAnchor

IfcPlate

IfcDiscreteAccessory

IfcFastener

IfcMechanicalFastener

IfcSpace

IfcBuilding

IfcBuildingStorey

IFC Classes that are not backward compatible with older BricsCAD versions:

IfcBuildingElementPart

IfcBuildingElementProxy

IfcDistributionElement

IfcElectricDistributionPoint

IfcElectricalElement

IfcElementAssembly

IfcEquipmentElement

IfcProxy

IfcTransportElement

IfcVirtualElement

IfcActuator

IfcAirTerminal

IfcAir TerminalBox

IfcAir-To-AirHeatRecovery

IfcAlarm

IfcAudio-VisualAppliance

IfcBoiler

IfcBurner

IfcCableCarrierFitting

IfcCableCarrierSegment

IfcCableFitting

IfcCableSegment

IfcChiller

IfcChimney

IfcCivil Element

IfcCoil

IfcCommunicationsAppliance

IfcCompressor

IfcCondenser

IfcController

IfcCooledBeam

IfcCoolingTower

IfcDamper

IfcDuctFitting

IfcDuctSegment

IfcDuctSilencer

IfcElectricAppliance

IfcElectricDistributionBoard

IfcElectricFlowStorageDevice

IfcElectricGenerator

IfcElectricMotor

IfcElectricTimeControl

IfcEngine

IfcEvaporativeCooler

IfcEvaporator

IfcFan

IfcFilter

IfcFireSuppressionTerminal

IfcFlowInstrument

IfcFlowMeter

IfcFurniture

IfcGeographicElement

IfcHeatExchanger

IfcHumidifier

IfcInterceptor

IfcJunctionBox

IfcLamp

IfcLightFixture

IfcMedicalDevice

IfcMotorConnection

IfcOutlet

IfcPipeFitting

IfcPipeSegment

IfcProtectiveDevice

IfcProtectiveDeviceTripping Unit

IfcPump

IfcSanitaryerminal

IfcSensor

IfcShadingDevice

IfcSlabElemented Case

IfcSolarDevice

IfcSpaceHeater

IfcStackTerminal

IfcSwitchingDevice

IfcSystemFurnitureElement

IfcTank

IfcTransformer

IfcTubeBundle

IfcUnitaryControlElement

IfcUnitaryEquipment

IfcValve

IfcVibrationIsolator

IfcWallElementedCase

IfcWasteTerminal

IfcAlignment

IfcReferent

Export a structural analysis model

It is possible to export a line model of a structure using the BIMANALYTICALMODEL command. It can either be exported to CIS/2 or to IFC. Choose the Export and exit Command line option to open the Choose a filename and format for export dialog box, which allows you to choose the file type to export.

For more information and examples, visit the procedure article Analytical Model.

Import/Export Mapping of IFC files

When you Import/Export an IFC file in BricsCAD, all entities are imported/exported according to the default mapping. It is possible to import/export elements by special mapping and to exclude entities from import/export.

There are different txt configurations possible.

  • No text mapping
    All entities will be imported/exported according to the default mapping.
  • Import/Export an entity by special mapping
    In case of import, you first write the IFC class, followed by the BricsCAD class in which the entities should be imported. For example:
    IfcWall BimDbColumn
    In case of Export, you first write the BricsCAD class, followed by the IFC class in which the entities should be exported. For example:
    BimDbWall IfcColumn
    Note: When an IFC or BimDB entity isn't listed in the Import or Export mapping file, the default mapping will be used.
  • Exclude an entity from the Import/Export

    Write the IFC or BimDb entity followed by 'skip'.

    For example for Import:
    IfcWall skip
    For example for Export:
    BimDbWall skip

  • Import/Export only the listed entities

    List the entities that should be imported/exported followed by '* skip' on the next line. The asterisk refers to all not listed entities.
    * skip
  • Import/Export all not listed entities by the same special mapping

    Write the asterisk followed by the name of the class in which the entities should be imported.

    For example for Import:
    * BimDbWall
    For example for Export:
    * IfcWall
  • Import/Export entities by default mapping when using the asterisk

    If you used one of the two previous options to skip all entities except the listed ones or to Import/Export by special mapping, you can still Import/Export entities by default mapping. Use the same text as you use to Import/Export an entity by special mapping. Instead of writing a special mapping next to the entity, write the default class or write 'default'.

    For example for Import:
    IfcWall BimDbWall or IfcWall default
    For example for Export:
    BimDbBeam IfcBeam or BimDbBeam default
Note: Use the rules explained in Export Mapping of IFC Files to create an Import/Export Mapping file.

Export Mapping of IFC Files

  1. Start from a similar model in BricsCAD with all the building elements classified.
    Note: If the elements are not classified, run the BIMIFY command to classify the model.
  2. The building consists of several building elements: walls, slabs, doors, windows etc.

    A custom Export Mapping file will be created to only export the geometry of the building without windows, doors or spaces.

    Note: If you export the file without a mapping file, all the elements will be exported in the default IFC class.
  3. Open a new TXT file to create the export mapping file. Use an ASCII text editor, e.g. Notepad.
  4. Follow these rules to add the text in the TXT file according to Import/Export Mapping of IFC files:
    • For export mapping, write the BimDb entity followed by the IFC entity. Separate the two words by a single Tab. Do not use a space or multiple Tabs to align the IFC classes. The lines with a space or multiple Tabs will not be used for Export Mapping.
    • Only write one command per line.
    • If a composition is attached to a wall in a BricsCAD file, the wall will be exported as IfcWallStandardCase instead of IfcWall.
    Note: When a building entity is imported/exported by special mapping, the properties of the element will change according to the default properties of the new category.
  5. Two categories need to be added in the TXT file to create the Export Mapping File for this model.
    • Exclude windows, doors and spaces.
      The BricsCAD file contains normal windows and curtain walls, exclude both.
      BimDbWindow skip BimDbCurtainWall skip BimDbDoor skip BimDbSpace skip
    • Export beams by special mapping.
      Some walls are classified as beams in the current BricsCAD file. These have to be exported as walls.
      BimDbBeam IfcWall
    • The resulting file looks like this:
      BimDbWindow skip BimDbCurtainWall skip BimDbDoor skip BimDbSpace skip BimDbBeam IfcWall
    Note: You can also create a file where you include the entities you want to export, followed by '* skip'. This will give the same result.
  6. Save the file to your computer.
  7. Go to the BricsCAD file you want to Export.
  8. Go through one of the following steps.
    • Type SETTINGS in the Command line and press Enter. Go to BIM > Import and Export > IFC > Export mapping file path. Click on the three dots and select the mapping file on your computer.
    • Type IFCEXPORTMAPPINGPATH in the Command line.

      You are prompted: New value for IFCEXPORTMAPPINGPATH <"">:

      Copy the path of the destination file in the Command line and press Enter.

  9. Type Export in the Command line and press Enter or click the BricsCAD icon in the ribbon and select Export to export the file.
  10. Select the desired IFC file format in the Save as type list and save the IFC model to your computer.
  11. To check if the IFC file is correct you can open the file in an IFC viewer or you can import the file in BricsCAD without an Import Mapping file. Type IMPORT in the Command line, Press enter, select the file on your computer and click Open.
Note: The same workflow can be used to use Import Mapping of IFC Files. To use the import mapping, the model should contain BIM information. Start from a model that is divided into different IFC elements.

Export Geographic Location to IFC

When geographic Location data exist in a BIM model, proper export of said data is supported in the IFC export.

In the Spatial Locations Manager, with the Use Geographic Location from GEO dialog box, you can choose whether the geographic location information from the Geographic Location dialog box should be used, or the information provided in the Spatial Locations dialog box.

  • If this setting is False: the Latitude, Longitude, and Elevations from the Spatial Locations dialog box is exported. No CRS (Coordinate Reference System) is exported.
  • If this setting is True:
    • IFC2x3: Longitude, Latitude, Elevation from the Geographic Location dialog box is exported.
    • IFC 4: Longitude, Latitude, Elevation + CRS (Coordinate Reference System) from the Geographic Location dialog box is exported.

Model origin

Defines where to position the model with reference to the World Coordinate System (WCS) origin. Placing the IFC Global Coordinate System in WCS origin can result in a model positioned far from the origin.

The options are:

  • Place IFC Global Coordinate system in WCS origin.
  • Place IFC Project Location in WCS origin.
  • Place IFC Site Location in WCS origin.

Guidelines for exporting colors and transparency

During IFC export, BricsCAD BIM includes colors and transparency settings in such a way that the model’s appearance in IFC viewers should resemble the appearance in BricsCAD BIM as much as possible. Due to limitations of the IFC format, in some specific cases, colors and/or transparency settings might not be exported correctly. Try avoiding the following scenario: within one block, set the color to By Block for some solids, and assign a specific color to some other solids. In the IFC export, the By Block solids will not have the block reference color assigned.