It is commonly used to create more subtle reflections such as on wet floor surfaces or in puddles.
Floor reflection unity.
From my understanding you create a material push the smoothness to 1 and then place a reflection probe in the scene and all the materials smooth enough.
More info see in glossary window that are used for editing the size and probe origin properties directly within the scene.
There are two buttons at the top of the reflection probe inspector a unity window that displays information about the currently selected gameobject asset or project settings alowing you to inspect and edit the values.
The effect descriptions on this page refer to the default effects found within the post processing stack.
More likely you d use a camera in the ceiling and probably want to process it with opencv.
Now i did realize that unity free has reflection probes.
With the leftmost button size selected.
I can t wrap my head around how do you make a floor that reflect the environment and just the floor.
I suspect that this will be the hardest part of what you need to accomplish.
This approach is very hacky but you can use the new reflection probes in unity 5 to easily create realtime reflections for something like a reflective floor.
Here s a quick tutorial on how to create realtime reflections in unity 5.
It may be possible to get some sort of sensors in the floor and then you re doing entirely custom things to read the data.