Parametric design is a way of generating the required forms using computer software. With this method, multiple solutions can be achieved based on the same rules by defining variable values.
"Parametric - a computer modeling process whereby inceremental decisions are defined in series and can be recalled and changed at any point in the chain of design descisions, whereby a detail can be defined before the whole and any change in any element can reconfigure the entire definition of the whole [Lynn, 2008]."
LYNN, Greg a Mark RAPPOLT. Greg Lynn FORM. New York: Rizzoli, 2008. ISBN 9780847831029.