Perhaps the living experience of each being connected by this "current reality" is no other thing than such an "exact fantasy", that includes complex rules and sequences on an amazing being .
On the other hand, some authors have tried to re-create quite exact fantasies, for example Tolkien, or Asimov. Such a fantasy that you are described is also described in "The Aleph" of Borges, where an large enciclopedia is found based on "fictive" cities, and kingdoms, including their fauna, flora, history, geography, philosophy; religion...
I have rather in my mind that kind of fantasy that we may find in Goethe's scientific works, like metamorphosis of plants or that of Novalis in his fragments... it has to do with a spiritualisation of thinking. It is the very thin treshold between art and science, not as a sum, but as an organic synthesis...