Engineers are currently resorting to observations of nature for making new designs. Studying the functioning of bodies of plants and animals has required them to be modelled and simulated; however, some models born from engineering problems could be used for such purposes. This article shows how topological optimization (a mathematical model for optimizing designing structural elements) can be used for modelling and simulating the way a stem grows in terms of carrying out its function of providing support for the leaves and a plant’s other upper organs.