The term ‘frequency’ refers to the shape or smoothness of the dome. It tells us how many struts are used. The higher the frequency, the more struts it uses and more triangles it has, so the closer the dome it is to a true sphere, making the dome rounder and stronger.
Every dome has 6 pentagons – the shape made of 5 struts, 1 at the top and 5 around the sides. To find the frequency of the geodesic pattern, simply count the number of struts between the centers of two adjacent pentagon patterns. The following figure, for instance, find a pentagon (highlighted in the figure) and the next pentagon. Then add up the number of struts between the centers of these two pentagons. The number is the geodesic dome frequency. We call the figure below a 4-frequency dome and 5-frequency dome. The frequency is commonly abbreviated as “V”, so a 4-frequency dome is called 4V, 5-frequency is 5V, and so on.
Notice that a dome is not always 1/2 of a sphere. Only even frequencies (i.e. 2V, 4V, 6V, etc…) have a dividing line exactly across the center of a sphere; odd frequencies (i.e. 1V, 3V, 5V, etc…) won’t divide the center line and are always slightly above or below the center line. This is why odd frequencies spheres come in 4/9 or 5/9 versions.
Frequency of Our Domes
The standard geodesic structures of SHELTER DOME range from 2-frequency to 7-frequency. If you still have no idea how to plan the size of your dome, feel free to leave us a message or contact us for some friendly advice. We are always pleased to explain the various options.