Offhand I would say the answer is "never" - NavisWorks are end tools for reviewing designs, not file converters. The export in NavisWorks is for coordination data, not model data. None of the export formats has anything to do directly with the model.
From the list, I can see 3DStudio can import anything NavisWorks can view, so what would be the point? The downside of NavisWorks being able to export model data would be to "unsecure" the NWD format, meaning somebody could take a published NWD file and make a useable (but inaccurate - very important, that).
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If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.