Actually I was just guessing what you did and why you chose it. Take the built in icosahedron. Scale it by 2.0 on the 2-fold axis. Then measure the longest diagonal. It is 11.21688. You report the radius as being 5.60844 which is 11.21688 / 2. I was just observing that this radius would always encom...

Hi Rob, It appears the value you give for a polyhedra radius is the maximum distance between centroid and the vertices. Is this the excepted definition of polyhedron radius? My thinking is that this radius, if swept out as a sphere would contain every possible point in the polyhedra. Faces and edges...

Ulrich, These are very nice. The second one, upon opening, I find is actually a 2D spiral like a snail shell. Interesting. Stella is downsizing each icosahedron as it goes. These all probably have some fractal properties. What the actual fractional dimension is would be a math problem. I would say t...

Hi Rob, I don't know that this is truly fractal. I got this idea while working with Jim's Molybi polyhedra http://www.orchidpalms.com/polyhedra/rhombic/molybi/molybi.htm Take any antiprism (or prism for that matter) and shrink one of the major polygons on one side, but keep it regular. Attach that t...

It's a good idea, after our other discussion I was already thinking I should add them, although the labels are not terribly user-friendly and a drop-down list showing all the subsymmetries would be pretty long! It actually makes a lot of sense to split the symmetry group into a rotational part and ...

Hi Rob, Since this came up over at the Antiprism forum I thought I'd put it here. Other Stella users might want to comment on showing Schoenflies notation symbols for symmetry. For others reading this, the reason this came up is that I was confuse because of the use of term "Pyramidal Symmetry" when...

Hi, This gave me an idea. I took a platonic or achimedean and added the base and its dual. Then I did a convex hull. If we do this a number of times we come up with more and more intricate polyhedra. Any other polyhedra could be used but it must be such that the dual doesn't have infinite faces. If ...

Hi Rob, You mentioned how Stella can't determine the compound of 3 8/3 prisms from an OFF file. Does this imply then that it can be stored in a stel file? The problem is trying to form such a compound in the first place. If I try to do that in Stella, it becomes not-a-compound before I'm ever allowe...

Rob, Thanks for the tip. Once clicking Same Color for Chiral Face Pairs then if the polyhedra is isohedral but has mirror image faces, it will be all one color. Noting the mirror image by e.g "2: Reflection of face type 1" would spell it out. This same thing applies to mirror vertices as well. When ...

Hi Rob, Note that in Stella, mirror images are also counted as two separate face types. This can be useful sometimes, but might be misleading at others. For example, see how the dual of the truncated tetrahedron appears with two differently coloured faces. For me the dual of the truncated tetrahedro...

Hi Rob, I have a question pertaining face types and vertex types. I made a compound which is 15 8/3 dipyramids in icosahedral symmetry. Stella lists 4 face types which are all described identically. The dual list 4 types of 3 valence vertices all on the same radius. If there are indeed more than one...