The OpenStudio Application Geometry->Editor tab has the ability to import IDF geometry to update your model with. From the Geometry Type drop down, you would select IDF instead of FloorspaceJS. If you have already associated your model with a FloorspaceJS file, you can delete the floorplan.json file inside of your OSM companion directory. The import IDF method uses object names to detect updates vs new geometry so you will not want to change object names in your IDF editor.

The workflow works best when you start with one geometry source (e.g. FloorspaceJS, IDF, gbXML) and stick with that same source throughout. The assumption was that you would use some separate editor to manage the geometry and switching editors would not be allowed. I'm not sure what workflow you have been using but you can trick the app into thinking you have been using IDF all along by placing a file named geometry.idf in your companion directory (make sure to rename any floorplan.json, gbXML.xml, or geometry.osm files that exist).

If you want you can also copy the code in the geometry editor tab to import an IDF and translate to OSM and the merge with current OSM into a measure or script.