Please Note: articles in English will be moved to my new blog on grasshopper3d.
For those who love spirograph may find it familiar. In Grasshopper, the definition looks like this:
Downloaded Grasshopper definition file: paramsurf01.ghx
In which I use Variable Expression component to hold the functions (parametric equations) for x, y, and z coordinates of the surface. Remember to set the data matching to Cross Reference so that u and v make up a 2D matrix.
And the result model of this exercise is: