4) In order for perspective to be accurate, what are the two qualities it requires?

Fixed viewpoint and the imaginary meeting point of the orthogonal lines

Explanation:

For perspective to be accurate, it should have a fixed viewpoint from which all the presented elements are shown and the vanishing meeting point of the orthogonal lines.

A fixed viewpoint means that all the elements that are depicted on the art piece are presented as if they are seen from the same angle. When we observe the objects when we move the perception of them moves – the light, the size, the viewpoint, the shadows, etc. The elements should all presented following the one same observing point.

The vanishing point on the horizon means that if we were to draw the imaginary orthogonal lines on the existing lines of the one object, the lines would meet at the distant point and vanish one into another. This means the object is well presented as it is seen by the eye.