Hi,
the house and furniture were modeled by different artists who prefer different software: The house artist used Blender for the walls, doors, wallplugs etc. The furniture artist chose 3D studio max. These selections are based completely on personal preferences, no technical limitations. Both software could be used for both tasks.
Regarding the FPS: On our GTX980, there were no problems with the FPS, just some very rare micro judder from time to time. The judder mostly occures when “walking” around with the razer hydra controls, so I believe there´s something not perfectly optimized with this driver.
On our GTX770, the framerate drops to 69 in some of the rooms when there are a lot of details and high poly meshes. In other rooms, even the 770 has stable 75 FPS. For optimization, we lowered the polycount of some objects (not more than 100.000 polygons per object, mostly less than 10k) and activated some of the tweaks published in the UE4 forums.
Anyway, I am really looking forward for Rift-SLI… 