Making a perspective drawing - part 3
Perspective: Seeing where you stand
Carrying on from Part Two
Now to make a sphere:
Do you remember the plan of the circle you drew in steps 10 & 11? Like most plans, it represents a view of a circle from above, just like looking at a map. But a sphere looks like a circle from any angle, so this could also be a view of a sphere from the side.
Now think of this: if you cut a slice straight through a circle at any point the flat cut will always be a circle. The only difference (depending on where you make your cut) will be the size of this circle - its diameter (this is like imagining a sphere inside a tower block. On each floor the diameter of the section will be different)
Draw a line the same width as the two points where the circle crosses each of the horizontal lines. This is the width (diameter) of an imaginary slice through the sphere at each of these levels.
So if the sections of the sphere have different diameters at each level, by making a circle the same size and putting it on its own horizontal grid, you will end up with a set of circular slices that make up a sphere.
Tip: You only need new circles for the horizontal grids up to the middle line, because the top half will be identical to the bottom half
You can now draw anything using this system of perspective, as long as you have the patience. But patience is a problem (as well as all those lines). Imagine you wanted to draw a person, or a face? Well you could, but drawing them slice-by-slice would take years. This is why the drawing machine was invented.