• IFC Export for Structural Connection

Quick IFC Export Settings for Structural Connection

IFC in ArchiCAD allows structural engineers to use models created by architects. However, since structural engineers need to see only the load-bearing structure of the buildings, such as slabs, walls, beams and columns, the architectural models can be simplified with a customizable layer system in Layers and Layer Combinations, and through Partial Structure Display in ArchiCAD, as well as through the settings of the IFC saving procedure.

This document shows how the settings of IFC export affect the content and size of the models sent to structural engineers.

Model export can be performed with the File/Save as command. Set the output file extension to IFC_2x3 (*.ifc) in Save as type. A dialog box appears with all settings options collected under drop-down menus.

To start with the suggested initial settings, click Restore Default.

Units

Specify the units of Length, Angle, Area and Volume.

Export

Specify the way certain objects are handled.

IFCSite

Most of the structural software does not use Site data, in which case the No site option needs to be selected.

If Site and Mesh objects are needed, choose one of the four options and set it as Surface based. This will export a single surface based on the extent defined by a plan view.

Object/Lamp as BREP” and “Door/Window as BREP

If these checkboxes are enabled, ArchiCAD’s objects, doors and windows will export their geometry in BREP (Boundary Representation) format. This may result in a significantly larger file size than if they were exported without the geometry.

A BREP is a geometric object that is specified by its boundary faces.

Normally it is better to disable this flag, because a smaller IFC file is created, and the BREP geometry is only used for visualization in most structural applications anyway.

Export elements

Filter elements in the current ArchiCAD database for export. The possibilities are:

• All: Save every building element on every story of the building, visible or not.

• All visible: Save every visible element on every story.

• All on current story: Save every element on the current story visible or not.

• All visible on current story: Save every visible element on the current story.

• All selected: Save all selected elements on the current story.

Follow Partial Structure Setting

Enable this option to filter the 3D model according to the Partial Structure Display settings. If the Core Only option is active, only the load-bearing core skins of composite structures will be exported.

Default Door/Window Type

Area/Volume calculation

Extended Properties

Save Space boundaries

Save Space containment

Disable all these options, because they are not important for structural models.

2D Elements (Text, Fill, Line, Arc/Circle, Polyline)

Enable this option if texts and draft are needed in addition to the structural objects. Disabling the option reduces the size of the IFC file.

Custom Property Set & Exterior

Skip the dialog boxes by keeping these options disabled.

Person and Organization

It is recommended to enter some data here (such as ID etc.) for easier project identification.

Import

Settings of this dialog box affect the Merge command (File/ File Special) in ArchiCAD. With Merge, structural objects that will be reopened in ArchiCAD can be filtered by different rules (selection by structural type and/or item).

If subsequent import into ArchiCAD is not needed, disable (default) all Import options.

Enable Import options if structural objects are to be merged into one special layer or to be placed on defined layers in case you need to reopen the IFC file in ArchiCAD.

Miscellaneous

Keep the default settings (Restore Default).

It is recommended that you always have the Keep IFC Global Unique IDs (IFC GUIDs) enabled. When exporting a new IFC file, the IFC GUIDs currently in the model will be retained, rather than a new set created. Enabling this setting is the default option and should be used to maintain a consistent model if you are using other IFC-based tools.

Press OK to validate export settings and open the saved IFC file in the target structural software.

PDF Download

• The above article is also available in PDF format: QuickIFCExportSettings.pdf

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