Any scene can initially be seen as a composition of a series of forms that are all related to four basic geometric solids: the brick, the sphere, the cylinder, and the cone.
In this article we concentrate on the sphere, i.
e.
, we will detail its properties and its place in the overall scheme of a drawing.
Besides the obvious, perfect spheres that form the structure of, for example, a there are also those objects which are almost a sphere such as an egg or a cup.
The anomalies from the perfect sphere can sometimes be quite radical but the idea is to see that they are built on such spheres.
Once you see this you can make use of your ingrained sphere drawing skill.
This makes the drawing of a football (which consists of a sphere with a cone at each end) or a light bulb so much easier.
At first, when drawing an object that has an underlying spherical shape, it is good practice to draw the complete sphere first.
Afterwards, you can always make the necessary modifications to render the actual object.
With practice you will finally be able to dispense with the preliminary sphere and draw the spherical object immediately.
After you draw the initial sphere you should then ask yourself where the anomalies (bulges, less curved portions, etc.
) are located and add then to the perfect sphere.
To start practicing, gather a few spherical objects and draw them in any size you wish.
But try not to use too small a piece of paper.
Make sure you can swing your arm from the elbow and even on larger paper from the shoulder.
A sphere is of course a three-dimensional object and therefore occupies a given amount of space.
That means that it is not a flat object.
Therefore you should try to convey the bulk of the object.
Because you are drawing on a two-dimensional sheet of paper, the three-dimensionality of the sphere will be an illusion.
Such an illusion is created mainly through the appropriate shading.
Because in this article we only talk about line drawing we will convey three-dimensionality with a different kind of illusion.
This illusion is created by adding to the sphere some of the ellipses that lie on the surface of the sphere.
It helps to draw the lines of symmetry of the spherical object you are drawing.
If you lightly establish the lines of symmetry you will get a better idea of how to proceed with drawing the sphere and particularly how to proceed with the perspective.
Do not forget that spherical objects, just like any other kind of object, comply with the overall perspective of the scene.
Circles become ellipses with just the right amount of curvature so that they seem to go to infinity in a natural manner.
Some objects have only part of a sphere in their form.
Nevertheless, it is often beneficial to lightly sketch in the entire sphere.
This is particularly so if the object has neighbors that overlap.
The presence of the entire sphere often makes it a lot easier to see exactly where all the objects should start overlapping.
As mentioned before, in a line drawing (i.
e.
, a drawing where we do not explicitly use shading) depth or the third dimension is suggested by adding lines, ellipses, circles and other extra curves to the outline of the object.
But, eventually, you will also learn the skill of applying different values.
In the end, this will be the ultimate way of creating the illusion of three-dimensionality.
In fact, if you think about this for a while, you will realize that values (i.
e.
, darks and lights) are the only things that exist in a black and white scene.
There no such thing as a line.
In essence, a line is created because two neighboring spaces have different values, i.
e.
, one is lighter than the other, and only because of that do we discern what we call a line.
This is all you need to know about rendering line drawings of objects that have the sphere as their underlying geometric form.