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.
Space The element of art that refers to the emptiness or area around or within objects. Positive space refers to the part of the artwork that takes up space. Negative space is the area around that object.