Sometimes vZome lets you design interesting models, until one realizes that in a real Zometool model, multiple struts cannot be put into the same hole. The left of the picture for instance shows a fraction of the vZome model for the Compound of Ten Tetrahedra, requiring two red coloured green orbit struts sharing a pentagonal hole with yet another (green coloured) green orbit strut. In the last post and the penultimate post a first method was introduced how this interference problem can be bypassed. On the other hand, in another post it was shown that one can eliminate some struts by paneling the model. The latter is considered here as a second technique to bypass the interference problem of multiple struts in the same hole: when the two adjacent panels of a troublesome strut is 3D printed as one single object (see middle of the figure), internally reinforced along the shared edge, the strut itself does not have to be present in the model, as shown on the right of the figure:
This technique is applied here to build a complete physical model of the Compound of Ten Tetrahedra, around a Icosahedron with edge length b1. The hg2, b1 and b2 struts are standard Zometool struts. The green struts with orbit length (2φ-1)/10 had to be 3D printed. Although ridicously tiny, they play an crucial role during the building proces. The model requires also some purple orbit struts. Also these had to be 3D printed. The 60 panel objects, all of the same type, were printed using PLA in 10 colors, in a colour scheme adapted from Robert Webb’s paper model.
Only now, with the physical model in hand, I can fully grasp the ingenuity of this colour scheme. The panel object can easily be printed with the larger triangle laying on the printer bed. To prevent support structures for the smaller triangle, its surface is thickened. The model is quite difficult to assemble. The result however is very solid and beautiful. To conclude a picture taken just before finishing the model, clearly showing the Icosahedron of which this compound is a stellation:
