Understanding the Basic Rules of Perspective and the relationships between the Ground Plane and Picture Plane
The Guy at the Window
Now, this is where we start having an understanding of Perspective. Image 1, which I have labeled the illustration as ‘The Guy at the Window’. With this Illustration we can begin to see how it all works and you are going to be part of the process.
You are going to place yourself approximately two feet from a window where you can clearly see the outside world, does not matter if you have window panes, this will be your Picture Plane, as per the illustration, except you are two feet away and a distance that is just convenient and comfortable to work.
Now I want you to ‘trace’ what you see outside using the window’s glass as your Picture Plane. Use a removable marker, trace the outline of what you see taking care not to move your feet or body.
When you have finished stand back a few feet and look at your work. The first thing you would have noticed is the lines you have drawn don’t match anymore, you have moved, you cannot do that with your perspective drawing, once you have started your artwork that’s it!
The next thing you will notice, you have produced a perspective drawing that is accurate and you have created it on the Picture Plane. That is perspective, true to life! And you have used two tools to do so, the Ground Plane, because that is where you are standing, and the Picture Plane to produce your artwork onto.
The other point here is the Cone of Vision. Look again at the Illustration, image 1, and take a careful look at the Cone of Vision as it touches the Picture Plane; it forms a circled area that is very important to us. I want you to reposition yourself at the spot where you created your perspective drawing on the window and imagine you have such an area on your window.
This part is very important to you…
You will notice that you may have drawn outside of that circled area. Not a problem when drawing onto the window, but if I had said to you, ‘look straight ahead’ you would not have drawn outside that circled area. The reason you have done so is because you moved your head and or eyes to see the image, otherwise it would be ‘out of focus’.