A form is a 3-dimensional object on a picture plane.
Forms can also be 2-dimensional artworks that appear 3-dimensional
3-dimensional (3D) = has height, width and depth
For example, a triangle, which is 2-dimensional, is a shape, but a pyramid, which is 3-dimensional, is a form.
Form can be real or implied
A real form is something that is 3-dimensional meaning that it is something that exists in the real world and you can touch it and see it from more than one point of view.
An implied form is a drawing that looks realistic or that it has the appearance of having depth and dimension.
3 WAYS TO TURN A SHAPE INTO A FORM
1.Detailed contour drawing.
Although any drawing on a sheet of paper is regarded as a series of shapes, by adding detail and the illusion of depth, a drawing can become an implied form.
By adding cross contour lines to show depth and volume can also create the illusion of form
2. Adding value through shading
Shading creates the illusion of depth
Light values, middle values and dark values give the appearance of the object existing in 3-dimensional space. The presence of light values opposite dark values creates a sense of there being a light source and a shadow reacting to the light source.
3. Perspective
Perspective is an illusion that is created when an object appears to recede into space