Alternatively, you can space the seeds 6 to 10 inches (15.24 to 25.4 cm) apart and thin your seedlings out once they reach 4 inches (10 cm) tall. At that point, you should consider thinning them out so that they are 18 inches (45.72 cm) apart.
Volume - Arcy Art Original Oil Paintings Art Dictionary. Volume is the size, bulk and dimension of a particluar object. It is an object that is usually thick, nontransparent and exists solidly and three-dimensionally in space and it is not flat. In a painting a volume is represented with light and shade and usually in spatial situation to make the nonflatness clear.
Scale and proportion in art are both concerned with size. Scale refers to the size of an object (a whole) in relationship to another object (another whole). In art the size relationship between an object and the human body is significant. In experiencing the scale of an artwork we tend to compare its size to the size of our own bodies.