illusion of space

The Illusion of space I think is the dimensions of your drawing. Making it look like its popping out of the paper, almost like you can touch it. Its how you make the length, width and depth of the drawing to give it those effects, it makes an art piece more exciting if you give it the illusion that its coming at you. In a more specific description, you take regular 2D art and give it the 3D effect. I don't think its something that can be done easily, but it is most defanitly an amazing way to make art.