Classic AutoCAD Export (IFC2x3)

IFC Export for AutoCAD-based Products

For exporting data from AutoCAD-based products like Civil 3D, AutoCAD MEP, … to IFC some basic considerations are relevant.

The AutoCAD data must be structured for the IFC export. This is done in the “Style Manager” ( AutoCAD command: “STYLEMANAGER”). This command opens a dialog for creating and editing styles defining the appearance of objects in a drawing and most importantly for IFC export.

Styles are used in AutoCAD to define objects (such as walls, pipes, windows, …), documentation objects (such as 2D sections/elevations, property data formats and property set definitions), and multi-purpose objects (such as layer keys, classification settings, material definitions, …).

Creating IFC classes and Assigning

First objects are selected to whom the classifications apply to. After that – or before classifications are created. In the top right corner of the “Classifications” window there are buttons for adding and removing classes or assigning property sets to classes.

The structure for IFC classes is corresponding to the respective IFC schema. Subclasses can be created by selecting a parent class.

Now for each class selected property sets can be assigned.

Properties, Property Data Formats and PropertySets

The creation of properties follows strict rules.

Before creating a new property, one must check if the required data format for this property already exists. If not, a new style must be created in “Property Data Formats” (context menu -> New) .

For this manual the file “IfcPropertySet_Definitions.dwg” was used as prototype drawing

Now a new property set is created, classes and properties are assigned to it. (for this manual it is “Pset_BridgeCommon).

- General: Define name of Pset, add description

- Applies To: Assign objects (Civil Bridge)

- Classification: Select IFC class (IFCBridge

- Definition: Add properties.

Now those properties can be assigned to AutoCAD objects by clicking the “add property” icon – marked with a red arrow in the figure below, and selecting Pset (here: My_SpecialWall_Pset).

Left side: Assignment of Pset My_Special_Wall, right: Pset My_Special_Wall assig- ned, value “I am special”

Now the data can be exported to IFC.

During export

- the respective IFC schema is selected

-Object types are selected for export

-Ressources and Assignment are selected Finally, the selected data is exported

Finally, the selected data is exported.

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