Development of perspective projection:

Certainly, there is still one more major item missing, before we can look at a computer display or plot and perceive it just as we see a real object, namely the stereo vision we experience with our two eyes. That too is now available, with software producing two colour-coded, polarized, or alternating images for left & right eyes, and a set of special glasses to merge them for the observer. Actually this technology is very much in use by architects who wish to show off their latest creations to their (rich) clients and for doctor who wish to plan and rehearse microsurgery of the brain or heart.

The development of perspective projection made constructed objects look more realistic. But for a realistic scene, we should only draw those lines and polygons which could in fact be seen, not those which would be hidden by other objects. What is hidden & what is visible depend upon the point of view.