Reading the Wolfram Research page on the tetrahedron,[1] I came across the simple volume formula: V = (1/6)[a dot (b cross c)] where a,b,c are vectors from the...
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David Chako
dchako@...
May 1, 2000 6:59 pm
... This is an elegant formula! Thanks for cluing me in. ... Wait a minute ... if you tetrahedronize the octahedron in the "natural" way, don't you get 8...
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Kirby Urner
pdx4d@...
May 1, 2000 7:16 pm
... Yes, sorry, a mistake. 8 tets with 90-90-90 angles at one vertex. Here's from the Octahedron class: def volume(self): # define a tetrahedron using one...
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Kirby Urner
pdx4d@...
May 1, 2000 7:41 pm
Also, I'd like to mention that this stuff works equally well using Tom Ace's definitions of dot and cross products for quadrays. In the last example, I...
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Kirby Urner
pdx4d@...
May 2, 2000 3:50 pm
Spendy RBF artworks on display, for window shoppers and those with the big bucks: http://www.solwaygallery.com/Pages/about%20bf.html Kirby (thanks to Joe Moore...
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philip szeto
flexsz@...
May 5, 2000 4:52 am
Bucky's numbers always stay an irrational. ... From: "Tom Ace" <crux@...> Reply-To: synergeo@egroups.com To: synergeo@egroups.com Subject: Re: [synergeo]...
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Kirby Urner
pdx4d@...
May 5, 2000 6:38 pm
An Update from Urner May 5, 2000 I've been continuing my web-based curriculum writing projects, which these days focus on the interface between traditional ...
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Kirby Urner
pdx4d@...
May 5, 2000 8:02 pm
Re: http://www.teleport.com/~pdx4d/kiyoshi.html I originally wrote this article for Friends Bulletin, the editor of which suggested I forward it to Friends ...
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Kirby Urner
pdx4d@...
May 7, 2000 11:59 pm
New quadray method: Volume of tetrahedron = ... (1/4) | b0 b1 b2 b3 | ... where quadrays a,b,c are vectors from any corner of a tetrahedron to the other 3...
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Kirby Urner
pdx4d@...
May 8, 2000 7:10 pm
I'm not presuming any synergeo subscribers are wanting to study postings such as this one at this time. It presumes you're neeeding to tune in a specific high...
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Kirby Urner
pdx4d@...
May 8, 2000 10:34 pm
The power of object oriented programming seems especially clear to me in that I ended up making no changes to my Quaternion class, which contains stuff like: ...
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Kirby Urner
pdx4d@...
May 9, 2000 7:30 pm
... <<snip>> Sigh. Not unusually, just when I thought I had it all nailed down, I found a bug in my coords.py module, which made cross product asymmetric...
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Kirby Urner
pdx4d@...
May 10, 2000 3:35 pm
... Your example of using Logo and geoboards to teach geometry sounds closest to what I'm doing -- using a different language, Python, free and cross-platform,...
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lgeller@...
May 11, 2000 10:32 pm
Could someone clarify the role of the rhombic dodecahedron in relation to the closest packing model of the IVM? In my class today we made a VE out of ping-pong...
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Kirby Urner
pdx4d@...
May 12, 2000 12:05 am
... Hi Lou -- Each IVM sphere is encased in a rhombic dodeca. RDs pack together without gaps. Spheres touch their RD encasements at the diamond-face centers,...
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Jim Lehman
bcat@...
May 12, 2000 12:32 am
Lou, another admittedly simplistic way to think of this is to imagine replacing those spheres with marshmallows. Form your hands around the cluster and press...
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philip szeto
flexsz@...
May 12, 2000 1:33 am
Dear Kirby: See how you have Scalers and Quaternions: The advancement in language opens up the possibility of many catenaries, where its stuck in Newton-grapho...
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philip szeto
flexsz@...
May 12, 2000 2:04 am
Dear Kirby: See how you have Scalers and Quaternions: The advancement in language opens up the possibility of many catenaries, where its stuck in Newton-grapho...
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philip szeto
flexsz@...
May 12, 2000 3:13 am
Dear Tom Ace: I really thought this deserved answering because its the tour de force of the mind that created the books. The books need following up with over...
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philip szeto
flexsz@...
May 12, 2000 5:20 am
This being my favorite url. Here's one for the group. Everybody probably already seen it, any, so here: IT'S SIMPLY _POVA RAY DEE_...
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lgeller@...
May 12, 2000 10:50 pm
Thanks for the good info (KIrby and Jim)-nice to know some expertise is at the touch of a few computer keys- Another question-what is the volumetric...
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lgeller@...
May 12, 2000 10:59 pm
I forgot to say that I used the GIF animated picture of the hierarchy on Kirby's web site in class today and the kids thought it was really cool-I think it...
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Kirby Urner
pdx4d@...
May 12, 2000 11:22 pm
... He thought he did but he goofed. Fixed for e-text version based on notes he made about how to patch. Sphere volume is just 4/3 PI r^3 * syn3, where syn3 =...
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Kirby Urner
pdx4d@...
May 12, 2000 11:35 pm
... Wooden dowels with surgical tubing. Dowels easy to find in hobby/hardware stores, but rubber tubing not so easy. Get sample dowel first, try to find...
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Kirby Urner
pdx4d@...
May 13, 2000 3:01 pm
... Actually, I got that backwards. Since tubing options most limiting, get same tube segment first, then find dowel to fit... Kirby...
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Jim Lehman
bcat@...
May 13, 2000 10:16 pm
I found surgical tubing easy to come by at a medical supply store. Could be a pharmacy would have it. Jim...
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rhombidodec@...
May 13, 2000 10:54 pm
To all synergetics-philes: My research group at Polytope Press has developed a new theory of the atom based on synergetics. Our atomic model works flawlessly,...
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Kirby Urner
pdx4d@...
May 13, 2000 11:04 pm
... <<SNIP>> ... You jump to asking for contacts without sharing anything at all about your atom model, other than the fact that no one seems to want to...
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Jim Lehman
bcat@...
May 14, 2000 3:07 am
Your work sounds interesting. Your email address involves the rhombic dodeca. Is there a special significance here? Are you able to share in this forum...
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rybo6
rybo6@...
May 14, 2000 2:47 pm
Not sure how _new_ the "ring theory" of atom is but it may be related to synergetics. I happened upon ring theory, on the net, a few months back and thought ...
