The size of the exported JT files is roughly 10 to 15 times to big. It look like that the building data use a configurartion which may fit in engine manufacturing or rocket sience where fine granularty and exact geometriey is requiered. At least the number of created elements in building and architectural data have to be reduced to get JTs which are perfomant in viewer application.
(Test environment: Microstation Connect v17)
Here is the structure I need for furhher JT processing (see attachment Siemens PLM Teamcenter 13.1 64-bit)
First improvements with the Microstation Connect 2023v2. But the JTs are still too big. It is possible to map the layers in the JTs, but the cells contained in the layers are still missing.
We are experiencing this issue as well and believe it should be prioritized in the backlog.