I have several large projects on the go, bulk quantities of the wedding invites and the photo frames. While those parts were cutting I needed something else to work on. My 15 great circle model was inspired by a challenge on the Make blog. When the model got featured on the blog, the new article issued an additional challenge to make the 25 and 31 intersection model, so I duly stepped up and I present to you the 31 circle model.
Made from card stock and 180 separate pieces, this model follows a similar construction to the last one. I used Cinema 4D (yes I know it's an animation package) to subdivide the basic 'buckyball' (football) shape. Then I subdivided each face to get the right number of intersections. This gives me the angles for each of the parts, pepakura unwrapped the model, and inkscape turned it into a sphere for me. Each edge has exactly two thicknesses of card to keep it looking uniform. More photos of the parts and construction technique are included below. (svg here)
4 items /4 weeks
The model is made up from two basic 'arrowhead' shapes, the smaller ones make up the pentagons and the larger ones make up the hexagons. These shapes connect together to form a diamond shape (2 large heads) and a kite shape (1 of each type). The diamonds have a solid outer edge and are ready for gluing together.
The shapes start to assemble and form some interesting patterns along the way, the one on the right looked particularly heart shaped (not so much in the photo though)
This was where I decided that it should be made in a different colour to white (white shows up the smudges badly) so I started again in purple and I made some new pretty shapes.
Larger assemblies started to look very bowl shaped, I expect you could make some very nice gifts from them.
A full model requires 60 of the smaller arrows and 120 of the larger arrows. I'm lucky because I can laser cut them all but the assembly still takes hours. Hope you have fun if you make your own up.