Hello ,
Thank you for posting in the community and the logic for Twinmotion is determined by the Collapse Method you choose, if you want to import elements and group them by the material then you should use Collapse by Material, otherwise if you use Keep Hierarchy each element will be imported and the material will not be linked to each element thus having to reapply the proper materials to new elements coming in.
Collapse Methods Details:
Keep hierarchy
Select this option to retain the same geometry hierarchy that is used in your source file. In Twinmotion, all objects will be separate and have their own pivot point, so you can move and manipulate them independently. Selecting this option also allows you to view BIM information for each element in your scene.
This option is useful if you want to create phasing groups and scene states. All objects inside your scene will be separate, making it possible to hide and show them as needed.
Retaining hierarchy is also useful if your scene contains place-holder objects that need to be replaced by Twinmotion objects, as you will need each object to be separate.
Note: Although keeping the hierarchy is sometimes necessary, selecting this option will increase the size of your scene in Twinmotion.
Collapse by material
This is the recommended option and is selected by default.
This option optimizes the model for real-time rendering, as it reduces the number of objects that are imported into Twinmotion — all objects that use the same material are collapsed into one single group. If a material is modified on any of the objects in the group, it will also be modified on all objects in the group.
Collapse all
Select this option to import objects or scenes as a whole. In Twinmotion, the entire object or scene will be grouped as one element and controlled by one pivot point only, making it easier to move, select, or delete, or to save in the User Library.
Hope this makes sense and let me know if you are still having issues if you picked Collapse by Material?
Kind regards,
Vincent B.