maybe not 3d such as sins but a 3d map.
That's minimal, in my mind.
And here's why...
Polaris is above our Sun. And Alpha Centauri is NOT on the galactic flatened plane.
We've had a loooong extenuation thread "argument" in the past, but i can't seem to find it anymore, if only the Forums search would work i'd link it all here.
In summary, i was going for a rather simplistic cubic 3 layer thick (or 5 in total) that had mid, below and above grids on the zyx planes. IIRC, everyone claimed memory lags and a stupendous CPU strain.
All i know is that i could get INTO a nebulae rather than hover above the immensity of true space.