Spider is a Grasshopper plugin written in C#. It focuses on the structural form-finding method that can simulate different models of hanging chains.
A catenary curve, or a hanging chain, is a model that assumes certain geometry under its own weight when supported only at its ends. It was first described by Robert Hooke in 17th century – "As hangs a flexible cable so, inverted, stand the touching pieces of an arch". This form-finding model is very common in architecture and engineering for generating the equilibrium of arches and for designing bridges. Perhaps, the most famous models of hanging chains were made by Antoni Gaudi for his work on Sagrada Familia. But, it can also be found in nature – the silk on a spider’s web forms multiple interconnected catenaries.
There are two main components than are able to perform the simulation. The first one will generate only the final result and the other is able to visualize each iteration. The user is able to construct different types of chains, anchors and 3 categories of loads – point, linear and regional. There are also components for extracting additional data from the simulation and for working with geometry.