No, not emotional perspective, silly! Perspective drawing, the technique for translating three-dimensional space seen by the artist into a two-dimensional picture plane.
Perspective as a system for artists was mostly devised by the painter Paulo Uccello, in the late Middle Ages. He was obsessed with the vanishing point, and also birds (cute!).
You can see him working out the concept in his most famous painting, The Battle of San Romano, where the fallen spears on the ground are used as perspective lines towards the single vanishing point. But these days artists most often use a two-point or even three-point perspective to draw a scene.
Last week I gave my students a horrible unpleasant homework assignment, and a tool to help.
I had them draw an U-Bahn or S-Bahn car interior from one end, which is the worst kind of observed perspective drawing- a deep, narrow space with many rectangular objects. In order to draw something like this, you need to accurately measure the angles of the objects in the scene as they appear to you.
Measuring the angles is hard, even using the traditional tool of a long paintbrush or pencil, because your brain is fighting you.
Your brain says, but I know that seat is really horizontal, it only appears to be angling away from me at 45 degrees. Your brain pushes the angle down, tries to make you draw it too shallow. I thought there had to be a way to fight this tendency of the brain to convert the visual information observed by the eye back into what it knows the space to be. So I made a little tool!
You can make this tool too, in about three minutes. All you need is the clear plastic lid of a takeout food container, a Sharpie, and a clock.
Cut off the edges of the lid so it’s a flat plane, and trace the clock face onto it using your Sharpie. Include the numbers! Take your plastic pane and use the hour hand of the clock face to measure the angles of the space you’re drawing, and say to yourself, 3pm, or 8pm, as you measure.
This will help you retain the information more accurately as you go to use it in your drawing.
In class I set up a diorama with the plastic kitchen organizer shelves I use to display my action figures and a 6″ Spidey figure. You can set up a diorama to practise this at home with any rectangular objects on a table, before you go out into the world to practise it in a cafe or bus.