I made this using Stella 4d: Polyhedron Navigator, which you can try for free at http://www.software3d.com/Stella.php.
The Rhombic Enneacontahedron, With All Faces Augmented With Pyramids
Reply
Tag Archives: rhombic enneacontahedron
From the Rhombic Enneacontahedron to an All-Kite Polyhedron
This is the rhombic enneacontahedron, one of the few well-known zonohedra. Its ninety faces have two types: sixty wide rhombi, and thirty narrow rhombi.
In the image above, the thirty narrow rhombi of the rhombic enneacontahedron have been augmented with prisms.
The next step in today’s polyhedral play was to create the convex hull of this augmented rhombic enneacontahedron. This produced the solid shown immediately above. To make the one shown below, I next used a function called “try to make faces regular.” The result is a symmetrohedron with 122 faces: 12 regular pentagons, 30 rhombi, 60 almost-square isosceles trapezoids, and thirty equilateral triangles.
Finally, I examined the dual of this symmetrohedron, which turned out to have 120 faces: two sets of sixty kites each.
The program I used to create these polyhedral images is called Stella 4d, and you can try it yourself (as a free trial download) at http://www.software3d.com/Stella.php.
A Blend of the Icosahedron and the Rhombic Enneacontahedron
This is the icosahedron, one of the Platonic solids. It has twenty faces.
The polyhedron below is the rhombic enneacontahedron, a well-known zonohedron with ninety faces.
Finally, here is a polyhedron which blends these two. It has 20 + 90 = 110 faces.
I used Stella 4d: Polyhedron Navigator to make these images. You can try this program for free at http://www.software3d.com/Stella.php.
A Twice-Zonohedrified Dodecahedron
If one starts with a dodecahedron, and then creates a zonohedron based on that solid’s vertices, the result is a rhombic enneacontahedron.
If, in turn, one then creates a new zonohedron based on the vertices of this rhombic enneacontahedron, the result is this 1230-faced polyhedron — a twice-zonohedrified dodecahedron. Included in its faces are thirty dodecagons, sixty hexagons, and sixty octagons, all of them equilateral.
Stella 4d: Polyhedron Navigator was used to perform these transformations, and to create the rotating images above. You can try this program for yourself, free, at http://www.software3d.com/Stella.php.
A Rhombic Enneacontahedron, Made of Zome
Zome is a ball-and-stick modeling system which can be used to make millions of different polyhedra. If you’d like to get some Zome for yourself, just visit http://www.zometool.com.
Normal and Expanded Versions of the Rhombic Enneacontahedron
The polyhedron above is the rhombic enneacontahedron. Sixty of its faces are wide (yellow) rhombi, while the other thirty are narrow (red) rhombi. The wider rhombi are arranged in twelve panels of five rhombi each. If those panels are moved outward from the center by just the right amount, the narrower rhombi have room to expand, becoming equilateral octagons:
Both of these rotating images were created using Stella 4d, a program you can try, for free, at http://www.software3d.com/Stella.php.
A Rhombic Enneacontahedron, Adorned with Jumpy Tessellations Which Resemble Rhombic Enneacontahedra
Software credit: I made this using Stella 4d, available here.
Building a Rhombic Enneacontahedron, Using Icosahedra and Elongated Octahedra
With four icosahedra, and four octahedra, it is possible to attach them to form this figure:
This figure is actually a rhombus, but the gap between the two central icosahedra is so small that this is hard to see. To remedy this problem, I elongated the octahedra, thereby creating this narrow rhombus:
It is also possible to use the same collection of polyhedra to make a wider rhombus, as seen below.
These aren’t just any rhombi, either, but the exact rhombi found in the polyhedron below, the rhombic enneacontahedron. It has ninety rhombi as faces: sixty wide ones, and thirty narrow ones.
As a result, it is possible to use the icosahedra-and-elongated-octahedra rhombi, above, to construct a rhombic enneacontahedron made of these other two polyhedra. The next several images show it under construction (I “built” it using Stella 4d, available at this website), culminating with the complete figure.
Lastly, I made one more image — the same completed shape, but in “rainbow color mode.”
A Cluster of Thirty-One Rhombic Enneacontahedra
The rhombic enneacontahedron has thirty faces which are narrow rhombi, and sixty faces which are wider rhombi. It is also known as a vertex-based zonohedrified dodecahedron. To create this cluster-polyhedron, I started with one rhombic enneacontahedron in the center, and then augmented its thirty red faces (the narrow rhombi) with additional rhombic enneacontahedra. In the image above, I kept the yellow color for all the wide rhombi, and red for all the narrow ones. In the next image, however, the rhombi are colored by face type, referring to their position in the entire cluster-polyhedron.
Software credit: I created this using Stella 4d, software you can buy, or try for free, at this website.
Eight Selections from the Stellation-Series of the Rhombic Enneacontahedron
The stellation-series of the rhombic enneacontahedron has many polyhedra which are, to be blunt, not much to look at — but there are some attractive “gems” hidden among this long series of polyhedral stellations. The one above, the 33rd stellation, is the first one attractive one I found — using, of course, my own, purely subjective, esthetic criteria.
The next attractive stellation I found in this series is the 80th stellation. Unlike the 33rd, it is chiral.
And, after that, the 129th stellation, which is also chiral:
Next, the 152nd (and non-chiral) stellation:
I also found the non-chiral 158th stellation worthy of inclusion here:
After that, the chiral 171st stellation was the next one to attract my attention:
The next one to attract my notice was the also-chiral 204th stellation:
Some polyhedral stellation-series are incredibly long, with thousands, or even millions, of stellations possible before one reaches the final stellation, after which stellating the polyehdron one more time causes it to “wrap around” to the original polyhedron. Knowing this, I lost patience, and simply jumped straight to the final stellation of the rhombic triacontahedron — the last image in this post:
All of these images were created using Stella 4d: Polyhedron Navigator, a program available at http://www.software3d.com/Stella.php. For anyone interested in seriously studying polyhedra, I consider this program an indispensable research tool (and, no, I receive no compensation for all this free advertising for Stella which appears on my blog). There’s a free trial version available — why not give it a try?
