Here is the Grasshopper implementation of the famous Evolution Door design by Klemens Torggler. The code I used here is from my course on Parametric Modeling. This Grasshopper algorithm is a good exercise for the basics of Kangaroo. I attached several goal objects to a special mesh object created in Rhinoceros. Kangaroo’s goal objects work as expected to simulate the folding door behavior. I used the goal objects to fix some of the corner points and fix the edge lengths. Thus, it mimics the real-world behavior of the system.

There are many interesting designs on Klemens Torggler’s website. I think I modeled the “Triangle” design of the Evolution Door in here. In the above video, I tried to show how it works. However, the special hinge system, which I have no idea about, can not be modeled here. Therefore, I left the rotations free, allowing many errors. Anyway, if you play enough with it, you can open and close it too.

Above are the Grasshopper definition and a screenshot while opening the door. Below are the Rhino and Grasshopper files if you want to test them. In the Parametric Modeling course, I show this Evolution Door algorithm as an introductory example for Kangaroo and Folding Structures. There are many possible improvements to this algorithm. For example, you can add the thickness of the door, fixing the hinge rotations better. Also, other types of systems from Torggler’s website can be studied and tested on screen.