Generative design is the process of using algorithms to help explore the variants of a design beyond what is currently possible using the traditional design process. Mimicking natures evolutionary approach, generative design uses parameters and goals to quickly explore thousands of design variants to find the best solution.
This process often results in designs that would not have otherwise been possible to create using the traditional design process.
Generative design allows for a more efficient workflow integration between designer / engineer and computer. In fact, both are considered co-creators of the final design.