buildingSMART Forums

IfcGridPlacement issues

I am currently working on creating an IfcGrid with the help of the software library XbimEssentials in order to place Elements.

Im having several Issues with this and I am starting to wonder if this part of the Standard is even properly implemented in common software applications ( Revit, SEMA ).

  1. In both Revit and SEMA, elements which have as positioning (IfcObjectPlacement) an IfcGridPlacement instead of IfcLocalPlacement are not positioned properly (each element sits on coordinates(0,0,0))

Using IFC viewers like " BIMcollab ZOOM " and" XbimXplorer " on the other hand shows the correct positions.

  1. Furthermore, elements in an example from my self are not orientated properly with IfcGridPlacement.PlacementRefDirection (when viewed in ZOOM or Xplorer the orientation remains in the X-Direction although in the IFC the orientation is set to the Y-Direction (IfcDirection -> setXY(0,1))

For more information here is my GitHub Issue i wrote on this topic at

“…/xBimTeam/XbimEssentials/issues/347”
(im not allowed to include a direct link in this post)

What version of the IFC specification are you using? If you’re using IFC2x3 (Revit cannot visualize newer versions), IfcGridPlacement is not included in the Coordination View MVD so it’s likely that the entity is not supported by most software viewers compatible with IFC.

Thanks for clarifying! I was using IFC4 ( IfcGridPlacement.PlacementRefDirection was not part of IFC2x3). I just think its strange that something as basic as some sort of grid placement would not be part the most commonly used MVD…