Search found 83 matches

by oxenholme
Mon Aug 17, 2009 12:22 pm
Forum: Polyhedra
Topic: Compound of Two Deltahedra
Replies: 10
Views: 26756

Compound of Two Deltahedra

Due to a never-ending tale of woe with broken computers I haven't got access to Stella at the moment... You know the "deltahedron" - same edges as the regular dodecahedron, pentagonal dimples each comprising 5 equilateral triangles, the polyhedron is actually a stellation of the icosahedron? If you ...
by oxenholme
Wed May 13, 2009 7:29 am
Forum: Polyhedron Models
Topic: Dodecahedral Shape-shifter
Replies: 2
Views: 13898

I'm lousy at mathematics, but does this imply that the volume of a regular dodecahedron is twice the cube of tau (1.6180339etc) times its edge length?
by oxenholme
Thu Mar 19, 2009 3:14 pm
Forum: Polyhedron Models
Topic: New Rubik's Cube-style puzzle made from paper
Replies: 4
Views: 14971

You might be interested that Martyn Cundy (co-author of Mathematical Models) showed me a "Rubik's" rhombicosidodecahedron that was made from card many years ago.

When it was first made it had worked well, but by the time I saw it it had started to come apart.
by oxenholme
Fri Aug 15, 2008 7:25 am
Forum: Stella Forum
Topic: "Stella Models" paper now online
Replies: 1
Views: 7688

We have several models in common. It's interesting to see the different approaches in the use of colour!
by oxenholme
Mon Mar 03, 2008 6:17 am
Forum: Polyhedra
Topic: What was your introduction to polyhedra?
Replies: 21
Views: 57751

Nordehylop wrote:oxenholme, I love your models. Are they all compounds?
Those in that pic are all compounds, but I have many more around the house of all types. I'll try to remember to take my camera home with me and post pics of a few more.
by oxenholme
Tue Feb 26, 2008 6:49 am
Forum: Polyhedra
Topic: Books about Polyhedra
Replies: 10
Views: 36468

Re: Cundy & Rollett

Indeed, if you don't have internal braces of some kind or stiffen the paper somehow, the finished five-cubes paper model has an annoying tendency to "pop in" at its octavalent re-entrant vertices. If you use double tabs and continue the tabs where the edges form pentagrams - do it pin-wheel style w...
by oxenholme
Mon Feb 25, 2008 4:06 pm
Forum: Polyhedra
Topic: Books about Polyhedra
Replies: 10
Views: 36468

Robert! - Polyhedra by Peter R. Cromwell is the book in which I learnt about the models that you discussed with Branko.

Uniform Polyhedra - Philosophical Transactions of The Royal Society - by HSM Coxeter, JCP Miller & MS Longuet-Higgins is a wonderful manual.
by oxenholme
Tue Feb 19, 2008 11:47 am
Forum: Polyhedron Models
Topic: Paper model choices. Scissors/knife? Single/double tabs? etc
Replies: 24
Views: 166738

Material - 160gsm coloured card (I have about 30 colours) Adhesive - Balsa Cement Scoring - I draw the net with a 9H pencil Cutting out - Stanley knife Tabs - double tabs I tend to make a template on thicker card. I staple together several sheets of 160gsm and pinprick through with an old compass po...
by oxenholme
Tue Feb 12, 2008 7:02 am
Forum: Polyhedron Models
Topic: What's the most complex model you've ever made?
Replies: 29
Views: 100177

Small inverted retrosnub icosicosidodecahedron From facial planes printed by Dino George No picture available. I half completed that snub with 4 triangles and a pentagram at each vertex (shaped like a narrow pentagram). Had to give up after complaints about the language from next door neighbour. For...
by oxenholme
Tue Feb 05, 2008 8:32 am
Forum: Stella Feature Requests
Topic: Tabs?
Replies: 9
Views: 25306

Good topic! I invariably use double tabbing now. Sometimes (e.g. regular compound of Five Cubes with dodecahedral symmetry) two or three facets have collinear edges, so I will use a common tab to maintain linearity and increase the rigidity of the model. I have to admit I find it a pain getting tabs...
by oxenholme
Tue Jan 29, 2008 12:45 pm
Forum: Stella Feature Requests
Topic: Creating convex polychora from vertices
Replies: 14
Views: 35111

That's the zonohedrification of the dodecahedron. Just load a dodecahedron in Stella and hit "z" (or "Poly->Zonohedrify"). Stella can then print nets for you, and show angles if you need them. Here's one I made out of paper: http://www.software3d.com/Enneaconta.php Rob. It looks good! I had in mind...
by oxenholme
Tue Jan 29, 2008 5:48 am
Forum: Stella Feature Requests
Topic: Creating convex polychora from vertices
Replies: 14
Views: 35111

As far as 4D OFF is concerned, they can be read in without cells or edges being defined, as this is what HEDRON produces. It does fail without faces though. A 3D OFF with vertices only does work as that was the method I used to generate a number of the sub-zonohedrifications of the dodecahedron at ...
by oxenholme
Mon Jan 21, 2008 9:14 am
Forum: Polyhedra
Topic: What was your introduction to polyhedra?
Replies: 21
Views: 57751

It can indeed be done in Stella, although it was a little tricky. Click here to download the .stel file Once in Stella you can print out the nets :D http://i225.photobucket.com/albums/dd237/RobertCWebb/Tetrahedra4C.gif Great! Can you show me how to do this with Stella? It would be interesting to se...
by oxenholme
Mon Jan 21, 2008 9:10 am
Forum: Polyhedra
Topic: What was your introduction to polyhedra?
Replies: 21
Views: 57751

Re: Six pentagrammatic prisms

Here's the compound of six with dodecahedral symmetry. And I couldn't resist making the compound of twelve by merging the six with its mirror image. :o Same set of 60 corners, now two prisms per each: http://members.aol.com/Dinogeorge/Twelve52prisms.gif Do you notice a certain similarity to Miller'...
by oxenholme
Mon Jan 21, 2008 9:08 am
Forum: Polyhedra
Topic: What was your introduction to polyhedra?
Replies: 21
Views: 57751

Re: Six pentagrammatic prisms

Dinogeorge wrote:Are you sure you don't mean six pentagrammatic prisms? Five of those prisms have only 50 corners, a number that doesn't evenly divide 120, the order of the icosahedral symmetry group.

:D
Yes! I meant six...