Help Group discussion • Geodesic dome • Based on icosahedron • 3V (3-frequency; each edge of the icosahedron is divided into three) • Only 2 triangle sizes • 105 triangles • 30 triangles define pentagons • 75 triangles define hexagons • The radius of this dome is 1 foot (unit radius) • The model can be scaled-up to the desired size using the SketchUp 'Scale' tool. (Use the <ctrl> and <shift> keys while using the scale tool) • Note that bottom-most level of edges do NOT lie flat on the same plane. This is a common characteristic of this geometric division of the icosahedron. If desired, the slightly-elevated vertices can be dragged down to lie on the same plane, but this will change the sizes of the triangles on the bottom tier, introducing additional triangle configurations (i.e.; you'll no longer have just two sizes of triangles). Alternately, a ring foundation-wall can be constructed having high and low points corresponding to the bottom vertices. This is not an uncommon solution, since the variation is not great, and often goes unnoticed.