Reimporting geometry

Hey guys,
I’m new to unreal studio / datasmith, but currently I’m working on an large scale archviz exterior project which I sent from 3ds max to UE4 via datasmith (UnrealDatasmithMaxExporter_4_19_18_3). I’ve got 24 houses with about 3000 objects. After I created the UE4 project, imported everything, set up the lights and change some materials I want to do reduce the number of objects by attaching/collapsing geometry in 3ds max.
I already tried to export everything again and import everything again (as suggested in the docs), but my material changes were lost and I got lots of duplicate objects.
Now the question ist: What is the most painless way to do a reimport?
Best regards

We have developed a much more robust version of re-import for 4.20. It keeps track of the issues you’re reporting and allows you to modify the upstream without losing your downstream changes. Unfortunately, it won’t be available until previews of 4.20. Watch for the announcement in June.