@Rick :
If a "Real instancing" system is present indeed we can go that way.
But does it works when you also have rotated your instanced models on the scene ?
Does it is really present in LE 3 ?
And lightening it in lot of engines "Broken" between neightbour tiles, due to vertex or shaders lighetning.
I tested and had same problem in LE3 with 3D tiles just snapped together on the editor.
Importing as one model and it looked good in LE3 this way.
On some engines, it's better to assemble your 3D tiles as one model in your modeler,the engine will deal with one model instead of managing 200 or 400.
On games using 3D tiles for floor , walls etc ... it can be more complicated : TorchLight uses it's own editor , and i've seen that it needs lot more CPU power on a laptop compared to some other games, caus all 3D tiles are processed as models.
Some AAA engines, uses instances of 3D tiling Rooms and corridors ( Oblivion game), not all tilling floor and wall 3D pieces.
Only testing will show you what is the best solution :
- import one level in one model
- import 3D tilling rooms , corridors
- import sub tilling models : Floor pieces, wall pieces