IFC export translator - Custom property not exported at component-level (URGENT)

[Johan Stinckens]

For a current project we have an building that consists of one basement parking that connects two above ground building volumes. It has been modelled in just the one PLN-file.

The estimation of the materials (information take-off) has to be done according to the volumes above ground.

For this I created a custom property "Gebouw_ID" (Building_ID) so that each 3D element holds the proper value -> "Kloosterstudios" or "Kloosterlofts".

This property has been included in the Property Mapping of the IFC export translator (AC26). Two mapping rules have been created so that the property will be added on the element as well as on the component level.

Sadly though, the exported IFC only holds the information on de element level, and not on the component level. This means that for all composites and complex profiles we can not assign volumes of the materials to the specific part of the building.

Strangely this all works well for other properties. Component_ID, which holds the name for each building element, is available at both element en component level. The same goes for the material classification VMSW - 2015.

As it worked for other properties before, I was confident in telling the project team that I would be able to provide this info in the IFC-model. Now it seems I cannot deliver what has been agreed upon.

Can anybody help me out here?! ASAP!!!

[Xandros]

Hey Johan

since you put the Gebouw_ID in the ifcBuildingElement it influences everything marked yellow. But in your case for the component you also need to add your custom property to ifcBuildingElementPart (marked blue)

[Johan Stinckens]

Hi Xandros,

Thanks for the speedy reply.

However, the other properties are also only defined at the IfcBuildingElement level. And these do get exported at the component level in the IFC file. It is since AC26 that properties can be exported on the component level..

The Geometry conversion preset in the IFC translator is set up as BREP with all elements exploded into parts. The components within elements are defined similarly to the elements they belong to. So the skins of a wall are all exported as IfcWall, the skins of a slab are all IfcSlab, and so on.

So these are not IfcBuildingElementParts and hence shouldn't need the property set for them.

As a test I just did what you adviced, but it is still the same. The property isn't available at component level.

Thanks anyway.

[Xandros]

The settings are the same settings I have used for my test.

The composite wall, which when normally selected is an ifcWall, still gave me ifcBuildingElementPart in my ifcViewer. So in the property mapping I added the property the way I described it in my first reply.

In your test did you by any chance map the property with the setting "only for components"? Have you tried the other option?

[Johan Stinckens]

Hi Xandros,

I have added both the element and component option as seperate values (not the "only for components" option).