Occasionally, users find that their Revit properties (Identity Data, Constraints, Other, etc) are missing in their exported IFCs when opened in SMC. The reason most often is that the IFC2X3 Coordination View 2.0 export setup was used in the IFC Export. By default, the IFC2x3 Coordination View 2.0 setup does not export internal Revit property sets. Therefore, if you want these properties in your IFC, you’ll need to modify the setup and mark the Export Revit Property Sets check box in the Export Property Sets tab of the IFC Export dialog.
Also, IFC2X3 Coordination View 2.0 does not export Space boundaries.
In SMC, components such as walls, doors, floors, etc. that bind a room normally have a Referencing relation to a space. This can be useful for instance in a check that every room has at least one door to enter/exit from. In the IFC Export dialog in Revit, with the Space boundaries drop down set to none, these referencing relations are not included in the resulting IFC. Therefore, if you want these relations, you’ll need to modify the IFC2X3 Coordination View 2.0 setup and set the Space boundaries drop-down box to either 1st Level or 2nd Level in the General tab of the IFC Export dialog.
Alternatively, you can use the IFC2x3 Coordination View* setup, which exports Revit property sets and has Space Boundaries set to Level 1 as its default setting.
More information on exporting to IFC from Revit can be found in the article Exporting an IFC File from Revit to SMC