Side 3 version
|Author||--Karl Horton 11:34, 29 October 2007 (UTC)|
A Geomag classic: pentagonal torii stitched together into a dodecahedron.
There is a technical problem with this construction: all of the rods along the red edges of the outer dodecahedron are too crowded: they cannot all remain with full contact on the 1/2" spheres. Nontheless, after the model is complete there is no tendency for the joints to slip.
Each module has 105 center rods, and 15 edge rods. So, there are 12*105 + 30*3 = 1350 rods in total.
Each module has 40 balls: 25 center, 10 edge and 5 vertex. So there are 12*25 + 30*10 + 20*5 = 700 balls.
The model weighs 27lb (12.4kg) but can, with care, be moved.
Rod to Ball ratio: 2:1
- Build a Pentagonal Torus module: it is helpful to build an extra module out of a different color and leave it nearby, because its really easy to get lost whilst building.
- Build another torus
- Strip the edge of one torus to join the two together
- Rest the linked modules on the hinge, and erect scaffolding poles to support the modules at the right angle.
- Now, resist the temptation to proceed onwards with modules. Instead, learn how to build the diamond-shaped tube in-place on the model. Use a contrasting color for the true edges of the dodecahedron to keep yourself orientated.
- It helps to use pentagonal panels to stabilise the build.
- Let the structure grow at first like a bowl, then like a dome. Keep the build balanced and keep evolving the model with an eye to the symmetry.