Parametric design gets recently more and more popular. It gives not known previously endless possibilities for designers. More software starts to incorporate parametric functions or generative components which give ability to design parametric objects or structures. One of the most popular is Grasshopper for Rhino.
“Grasshopper® is a graphical algorithm editor tightly integrated with Rhino’s 3-D modeling tools.“
The best way to learn it (to see what it does) is to watch the main tutorial from the Gasshopper web page. In 2h time it shows various examples how to use it in practice. Take a look.