3 and 4 centered Arches

This exploration started with making a 3 centered arch. I found this instruction guide for carpenters. It was an interesting experiment to make this parametric as the size of the arch is determined by the length of the spring line.

It was easy enough to script this up.

Then I turned it into a surface and used that for the start of my shelf design

A four-centered arch is similar, but there are a few more parameters. It produces a dome with a point at the top.

This is where the story gets interesting. While I was in college I worked for a stained glass studio. I have remained friends with the owner, Quint Foster, since. During my time there I helped them switch to CAD/Rhino and set up a plotter. Occasionally over the years they would call me with a design/architecture challenge and we would work on it together. I told Quint about this dome I was making and he threw a challenge at me – make a quadrant of 4 centered dome, full scale, to use as a mold for leaded glass windows. I used this script to get started and 3D printed a 1:12 scaled sample for him. We even used the script to get cost and material estimates.

You can download these scripts, but creating them from scratch is most of the fun. The 4 centered arch has a bit of tree management in it. That turned out to be a valuable experience when I started making the kangaroo bracing tower.

3-Centered Arch – link to grasshopper script

4-Centered Arch – link to grasshopper script