A section of a Quake 4 DM level being modeled in Blender (2.49). What's shown is how the mesh has been broken down into smaller sub section (sub-objects) based on how smoothgroups are needed in game. This may change depending on (VIS)portal optimisations that need to be done; the mesh may need to be broken down further to minimize 'over draw' (polygons being drawn when not visible by the player). Each section is then shifted to its own layer ("
M") in Blender which makes working on large projects easier to manage.
Further Watching -
https://www.youtube.com/watch?v=Uek64h_hF20
