Bumping the topic, as basic support for the IFC construction sequencing entities is now provided in the BlenderBIM Add-on. It is now possible to import schedules from Oracle Primavera (P6) XML and convert into IFC, and then do things like generate gantt charts.
It is still incredibly rudimentary, so watch this space.
Here is an example of a project gantt chart generated from the IFC model.
More info here: