Using geometric shapes allows us to build a simple view of the figure, helping us to simplify, understand and capture the complex human form.
You can see in this image the geometric shapes that were used to capture this 1-minute pose.
How does this work? An obvious start might be to use a sphere or oval for the head. Just draw the shape, nothing more. So, if you are using an oval, just draw the oval. Don’t try to capture nuances of shape or the facial features, just use the shape to capture the overall shape and position of the head.
You might then consider using a cylinder to capture the shape and position of the neck or torso. Again, just capture the overall shape and position. Don’t worry about the kind of detail you put into other kinds of drawings, or might add to this drawing later.
You might use more cylinders for sections of arms and legs. You might use smaller spheres for elbow and knee joints. But don’t do this automatically. Look at the figure, consider the pose and then decide which shape makes sense. It might be a triangle for the shoulders, or the foot, or a square for the head. You are trying to capture the figure in front of you – not what we consider a figure should look like.
Continue adding shapes to your figure until you have the whole thing. Work quickly. You should not be trying to draw your geometric shapes with trigonometrical accuracy. Re-draw or overdraw if you like, but keep moving the same way you would with a continuous line drawing. If you’re using this to block out the shapes for a more detailed drawing you will want to keep the lines light.
You should end up with something that looks a little like one of those posable, wooden maquettes you can find in art shops. Or it might look something like a robot. But you should also be aiming to produce something that looks like the figure you are drawing.
You can use this technique to help you see how to draw hands too. Do the same thing as with a figure: view the hand and decide which shapes you can use to build the hand. You might use cylinders to represent sections of fingers. Maybe spheres for the knuckles. The back of the hand might be built with triangular panels. The fleshy palm of the hand might best be represented by circles and ovals.
As with figures you should not focus on details. Just capture the overall shape and position of each part of the hand.
Keep practising. I found this technique very difficult at first, despite its seeming simplicity. I was stuck in the habit of trying to produce a realistic drawing first off, and found the use of geometric shapes frustrating. But stick with the technique, maybe using it for a few short poses next time you draw, and will start to see how useful it is to simplify that complex human figure.