Ifc Class for Hardscape & Softscape

Hi I’m setting up exporting a landscape model from Revit via the 2x3/TC1 data schema. Much of our hardscape is modelled as floors. The project civil engineer is modelling the sub-base for the hardscape so its only our surface finishes.

I’m wondering which is the best class to use. IfcCovering or IfcSlab…

We also have softscape modelled as a mixture of floor elements and topography. Revit has topography exporting as Ifcsite. I’d thought that IfcSite was a container defining the site geographic/geometric location and not for assigning modelled geometry too. Am I correct in this interpretation or can I use IfcSite for my Soft Landscape elements?

I also have fencing which I’m going to export as IfcRailing and street furniture/play equipment which I will export as IfcFurnishingElement.

Any advice on the correct classes to use would be much appreciated.




I would use IfcSlab.BASESLAB or IfcSlab.USERDEFINED, “Hardscape” (or whatever name you choose).

In IFC2x3, it was agreed by implementers/vendors to apply the geometric representation of the model directly to IfcSite, but this changed for IFC4 and IFC4.3. You can still add other objects inside the IfcSite “container”, with their own respective IFC mappings.

“Softscapes”, like planting areas, could be represented by triangulated 3D forms on top of the terrain, using IfcBuildingElementProxy… I know, it doesn’t sound ideal, but most of the focus on the schema development has been on the building, not the natural world context it sits in.

There have been some advances in IFC4.3, but a proposal to take it even further has yet to be funded and started.

@Argonaut If you are interested in this topic, as @jwouellette mentioned, there is a proposal for that realm of things that needs funding before starting.

The following is also a call for coordination to any interested in the urban and Land Management domain(s).