Hi Andras,
I helped develop this ceiling object with Applecore GDL programmers. We are an interior design company in the UK and we needed a product to help is develop produce ceilings layout in 3D that we could exported out to 3d max (vray). The product how to allow for flexible ceiling layouts (even with curved edges or atrium voids), different grid sizes, different ceiling tile detail, different ceiling services setting out (3 x 3 grid or 4 x 4 grid, with the flexibility to alter it to any size), ability to alter services type (luminaire, PL downlight, custom light fitting which we model in-house within our archicad model, or just an open blank space), ability to alter finishes to grid and tile, ability to turn grid frame on and off, ability to alter setting out angle of grid and origin of services setting out even ability to alter individual light positions within grid. Is has a few more extra functions which is great.
I have used this object for every archicad model / max model since its development. Works great with Bimx, although custom lights you have to be careful with not going overboard with the polygons. You have to be careful with large open plan offices as archicad can get a bit slow (depending on spec of comp), but can easily be managed with splitting the ceiling grid up which you can then easily align up.
All in all a great object and I would recommend it but like all things there are limitations but with a great imagination / adaptation most things can be overcome.
Hillsee