It’s been some time since we started to make the Zodiac Tent starting with its central zome, and much water has passed under the bridge. It is a good time for us to go over the zome particulars again and remind ourselves of the geometry and wonder of this structure. Some mathematics coming…
The term ‘zome’, invented in 1968 by Steve Durkee, comes from ‘zonohedron’ and ‘dome’. A zonohedron is a polyhedron (a solid in three dimensions with flat faces, straight edges and sharp corners) where every face is a polygon (a flat shape made up of straight lines) with symmetry under rotations through 180°. ie the faces are the same if you rotate them by half a turn. For example: rhombus, square.
The zome structure is built around a series of double helixes, a helix being a spiral with constant diameter. The building block of life is the DNA double helix.
DNA double helix
Zome helix side view
In the full zome cone each helix does a complete turn from the bottom to the top, and the top view is the Seed of Life, which, becomes the Flower of Life, when extended indefinitely. The Flower of Life is a sacred geometrical figure found all over the world.
Zome helix top view
Flower of life
There are (at least) two ways of constructing a zome: masculine and feminine.
In the masculine or polyhedral form, each half helix is split into n equal sections, making ‘n’ levels with straight struts of the same length in each level. The change in the angle which the struts make with the horizontal is constant between successive levels and this angle grows towards the top, so that the top struts are almost vertical. The vertical height of each layer is the same for all layers. The faces are rhombuses of differing sizes. (Diagrams thanks to Rene Muller).
Straight rib zome
In the feminine version, invented by Nicolas Causse, each strut is a true half helix of constant curvature.
Curved rib zome
Our first zome is of the feminine kind with n=24, and looks like this..,
Zome top view
The struts therefore have both a curve and a twist with 2 kinds of struts: lefts and rights, ie clockwise and anti-clockwise twists. We make our struts with laminated layers of wood, clamped onto a specially made jig. Lefts on one diagonal, rights the other.
Zome making jig
Making double curvature zome ribs
Be at home
In a zome
In the USA, Rob Bell, has taken the zome structure further in these magnificent temple sculptures, made up of plywood plates, for the Burning Man gathering. …
Zome is where the Art is.
Rob bell’s zome work
Rob bell’s zome work again
And here we have a model of The Zodiac Tent with the zome at its heart.
The zome in the zodiac tent