Zome Builder

What is a zome?

A dome built from rhombic panels instead of triangles. Geometrically it is a polar zonohedron: take a number of struts of equal length, tilt each one the same angle from vertical and spread them evenly around an axis. Every pair of them spans a rhombus, and every edge of every rhombus is one strut long.

That is the whole appeal for the builder: every strut is the same length. What changes from row to row is only the angles.

What do fold, rows and tilt mean?

Fold is the number of panels in each ring around the axis — a 10-fold zome has ten panels per row. Strut tilt is the angle of the struts from vertical: steeper makes the zome taller and narrower.

Rows are counted from the apex: z1 is the ring of panels around the top, z2 the next ring down, and so on. A full zonohedron closes at z(fold − 1). Start below z1 for an opening at the top; stop early for an open base you can stand in.

How are the panels numbered?

Every panel has a coordinate row,panel. The row is the same number the specs table uses, so 1,1 is the first panel of row z1 and 3,7 the seventh panel of row z3. Within a row the count runs from 1 up to the fold, the same way round the axis every time.

Tick Panel coordinates in the View section to write them on the model — useful for labelling the frames as you build, since panels in a row are identical but their neighbours are not. Rows stagger by half a panel going down, so 2,1 sits between 1,1 and 1,2 rather than straight below.

How do I make a door or a window?

Click any panel in the view to leave it out. It goes from the model and from the specs, and its coordinate appears under Excluded panels — click the opening itself, or its coordinate, to put the panel back.

Struts along the edge of an opening have nothing to meet, so they are cut square there rather than beveled; the rest of the row still gets the angle listed in the specs table. Openings travel in the share link with everything else.

How are the four struts of a panel joined?

One panel seen from outside. The four struts lap pinwheel-fashion: each runs fully into its corner and is cut back where the next one laps over it. All four are identical parallelograms, so both end cuts on a strut share one angle.

Use Explode struts in the View section to pull the four apart and look at the cuts.

Square or beveled struts — what's the difference?

Neighbouring panels meet at an angle. Here is a cross-section through one seam, looking along the shared edge:

Square struts. Going inwards the two frames converge, so each strut must stop short of the edge. They touch only along a line on the inside and leave a V gap on the outside. Quick to build; fine if the frame gets covered anyway.

Beveled struts. Rip the outer edge at β, half the angle between the two panels. The ripped faces meet flush, the outside closes, and the frames can be screwed together face to face. More cuts, but tight joints all round.

Tick Bevel struts in the Construction section to switch between the two.

Which surface do the measurements describe?

The rhombi — and therefore strut length, widths, heights and diameters — describe the outer surface of the frames. The struts hang inside that surface by Lumber depth, so the room inside is smaller than the numbers by that much, and a cover skin goes on the outside exactly at the drawn size.

Height is measured from the ground to the apex. The lowest built row stands on the ground.

How do I share my design?

Everything you set lives in the address bar. Press Copy link and paste it anywhere — whoever opens it sees your exact design. Your last settings are also remembered in this browser.

Can I build from these numbers?

The geometry is exact, but this is a design tool, not engineering advice.