We draw to learn to see and to analyse and understand what we are looking at. It is the basis of all good painting. There are many sub-topics that need to be discussed later, for example Perspective, color theory, line, texture, light etc, but here we will look at the endeavor only as a general framework for a better understanding of what is involved.
What we know and what we see!
There is what we see and there is what we know! Take for example a red cup. We see a cup, we see it is red, but do we immediately know what form it is? The cup is obviously cylindrical in form but depending on our viewing point it might not look cylindrical. For example when viewed from the top it will look circular and from the side, oblong.
Everything we see around us can be categorized and understood in terms of 4 basic forms, the cylinder, cone, cube and sphere. A common art school drawing exercise is to study these basic forms in isolation, to observe how light behaves when cast on them.
This basic lesson in the need to add layers of knowledge to what we know makes the drawing of what we see much easier. Many great artists have been quoted saying,
Draw what you know and not what you see!
If this is not grasped early you will forever be drawing as a beginner. Forever the victim of the way things look at one particular and transient moment.
Knowing a cup is basically cylindrical in form means that you don’t need to look at individual cups as a collection of strange shapes that need to be analysed in isolation. You only need to observe how they differ from a standard cylindrical form.