3D enviroment into plain 2D isometric projection


I am starting a project similar to Baldur’s Gate / Pillars of Eternity.
One of biggest issues in PoE is the loading times of new areas.
I would like to ask if any of the given ideas is reasonable:

  1. create 3D map with objects and then
    project it into a single picture. The
    problem is lighting on objects and
    also if the dept feeling will be ok?

  2. run a process that will be loading
    all adjescent maps to the current one
    with limited memory size (into RAM) so
    next map will be fetched faster upon
    entering it

I would also like to achive effect as given in the video:

When moving on stairs - please give me some pointers where I can read about doing it if you encountered similar solution.

You could split up a map in different squares.

if you are in a square, only load the other 8 surrounding squares and unload the others, so you don’t have a full map in memory at once.

For entering a house you could have an empty gameObject house. Add two child objects, one for the bottom part which stays visible and another for the roof that will become invisible. Now check if the player enters the house (maybe through an boxcollider marked as trigger). If true, set visibility to 0.

If the player exits, set it back to 1.