The Basics

Terminology

Line - the representation of a height, width, or length, between two distinct points

Horizon Line - is often referred to as the place where the Earth meets the sky, but it is more accurately described as being level with the eyeline of the observer. They tend to coincide, but are not the same. It is also commonly used as an anchor for Vanishing Points, but there are exceptions

Vanishing Point - the point at which lines that move away from the viewer appear to merge

Shapes - are flat, 2D objects that only exist with a height and width but no depth. These would include things like a square, circle, triangle, or five pointed star

Receding Line - lines that move away from the viewer and, due to the illusion of perspective, appear to converge at one or more vanishing points

Plane -  planes are flat 2D surfaces within the drawing. It can be something like a ceiling, wall, or floor plane; or a single side of an object like a box, be it the top, bottom, or side plane

Forms - are 3D objects, as opposed to a 2D shape. They have not only a height and width, but also length. These would include objects like boxes, cubes, cones, cylinders, and spheres

Edge - a line along the side of a plane

Corner - a point at the end of an edge where two or more edges meet

Contour Lines - a line that describes the outside of the shape or form it is applied to, like a topographical map