A Modular Method of Assembling a Geodesic （模块化组装测地线的方法）.pdfVIP

A Modular Method of Assembling a Geodesic Dome Frame John E. Hall While a 3v dome appears to be complicated when you look at all the individual elements, it is actually very simple. In the above picture you can see red struts, blue struts, and black struts. There are only three lengths of struts in a 3v dome. We call the red, or shortest struts, “A”. The blue, middle sized struts are “B”, and the black longest struts are C”. © 2009 Starship Enterprises John E. Hall Those three strut sizes are used to make two types of triangles, ABA and CBC triangles. Both are isosceles triangles, meaning that two sides are equal in length and two angles are equal. These two triangle types are assembled into pentagons and hexagons, each with a raised center. The ABA triangles form pentagons (red surrounded by blue) and the CBC triangles form hexagons (black surrounded by blue). For a 5/9 truncation dome there are six pentagons and ten hexagons, and five half hexagons. © 2009 Starship Enterprises John E. Hall This diagram shows how a 5/9 truncation dome would look if it were flattened by removing some of the bolts. For clarity some struts are shown twice to complete triangles. This is useful for seeing the pattern of pentagons and hexagons. The center of the diagram shows the top pentagon, formed by five A struts (red) surrounded by five B struts (blue) which are shared with hexagons. Below the top pentagon is a hexagon formed by six C (black) struts surrounded by six B struts, which are shared with other hexagons and pentagons. Below that hexagon is another hexagon. Between the two hexagons are pentagons. Below the lower pentagon is half of a hexagon. This pattern is radially symmetrical around the center of the top pentagon. The pattern to the right is 1/5 of