CAD file for 3v 5/9 Kruschke

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Brennan Oleary

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Jun 24, 2025, 11:28:12 AMJun 24
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Hi,

Is there anyone here I can hire to provide me with a CAD file for a 3v 5/9 Kruschke dome? I also need to do a 4v 7/12 Kruschke. 

I need a CAD file that preserves the parametric history of the parabola so that I can edit it with Fusion 360.

Thanks,
Brennan

Ray Foren

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Jun 24, 2025, 11:47:50 AMJun 24
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I created a function that runs in Autocad that creats a parabolic as a polyline. You set the perimeters. It was for horizontal boring under roadways. I have used it to create parabolic mirrors. It is yours if you wish...


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To view this discussion visit https://groups.google.com/d/msgid/geodesichelp/CANPiZmPD6r1XVgneNUvJNRhOMSUanjAGgUvwspPA8JKp3TM-Xw%40mail.gmail.com.

Dx G

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Jun 24, 2025, 12:34:24 PMJun 24
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Hi Brennan,
 I don't have anything for your for a CAD file.  However, I wondered if you had looked into these other options and decided to decline them for some reason.  The Kruschke domes have a flat truncation asset but there are other ways to get that without all the additional strut sizes.  The edge up config of a 3f icosa is flat and the other one I refer to is where Kenner illustrates how to flatten the bottom of a common 3f icosa vertex up.


--------- Forwarded message ---------
From: Dx G <Unknown>
Date: Wednesday, May 28, 2025 at 6:37:56 PM UTC-5
Subject: Re: Geodesic dome measurements
To: Geodesic Help Group <Unknown>

You might want to review Hugh Kenner's book, Geodesic Math. There is an entire chapter on truncations.  In one example he explains a method of replacing some struts at the ground level to eliminate the uneven bottom.  The rest of the dome uses routine struts, which reduces the number of odd sized struts.   
   He also explains some additional options that are often overlooked, such as using an edge-up configuration instead of the more common vertex-up orientation, since it can provide a true flat base from a great circle.

Dx G

Levente Likhanecz

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Jun 24, 2025, 1:25:53 PMJun 24
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its a radius=1 3V kruschke supposedly. (in collada format).
long time passed since i drawn these things. 


3V K.dae

Levente Likhanecz

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Jun 24, 2025, 1:28:43 PMJun 24
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Gerry has this excel file, for calcaulations
3v-icosa-Fuller-Kruschke-derivation.xls

Levente Likhanecz

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Jun 24, 2025, 1:57:55 PMJun 24
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this collada has no grouping of any kind.
(previous version has some tesselated icosa face bunched into groups)
please note there are some golden rectangle inside (which assisted the drawings)
3V K(2).dae

David Zhang

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Jun 24, 2025, 1:58:37 PMJun 24
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i have an stl file for a 5/9 dome.  can't seem to add it in a post though, says i can't reply to author

Levente Likhanecz

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Jun 24, 2025, 2:03:02 PMJun 24
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i guess you may reply even your own post (and attach the stl file). 
everybody supposed to see allmessage in the group.

David Zhang

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Jun 24, 2025, 4:54:43 PMJun 24
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maybe this will work.  i'm replying to the e-mail thread with attachments.

5:9 kruschke 4v.stl
7:12 kruschke 4v.stl

Levente Likhanecz

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Jun 25, 2025, 2:33:51 AMJun 25
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Brennan Oleary

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Jun 25, 2025, 2:15:40 PMJun 25
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Hi Ray,

Thank you, I would very much like to try it. 

Brennan

Brennan Oleary

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Jun 25, 2025, 2:31:03 PMJun 25
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Hi Dxg,

Wow, you are one seriously helpful member of this group, thank you so much for all your contributions. 

I do not have time to become a dome expert, it is just one area of my work. I was hoping to keep it simple and use the calculators at domerama. I would like to build a CAD file so that I can determine the dimensions of the panels I am planning to use. And then to make some pretty renderings for marketing purposes. 

Sorry, I missed your post about edge-up configuration. I have not declined such directions because I did not even know they existed, I know very little about geodesic domes.

Since there does not seem to be a CAD file with parametric data for the 3v 5/9 and the 4v 7/12, I will post them here once I have them, so that others can use them too. 

Dx G

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Jun 25, 2025, 10:03:43 PMJun 25
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Nice of you to say Brennan, but I'd say that was true of quite a few people who write on this list.  We even have lots of "lurkers" who read but don't chime in, but do periodically surface with helpful input, as you can see.

For others, if anyone does have a CAD file of an edge-up 3 frequency icosa Class 1 (Alternate), it would help Brennan out.  

Likewise, if you do have a 3f icosa Class 1 sphere, perhaps he (or you) could load it into CAD and render it as an edge up hemisphere.

Some of you may remember Ernie Aiken of Worldflower Garden Domes in Texas. He actually designed and sold a dome package (among a very large number of offerings) that made use of an edge-up 3f icosa hemisphere.   Interesting article he wrote in this issue of Dome Times.
https://blog.coldwellbanker.com/wp-content/uploads/2014/02/DomeHome1.pdf

In addition, if anyone happens to have a CAD file of the dome (also a 3f icosa Alt) that Kenner described in his book, where he altered a few struts at the base to give it a flat bottom, I'm sure he'd want to look at that also.

The Class 2 triacons, Octahedrals, and several others can generate good flat truncations, but typically have a larger number of different struts and triangle sizes than those variations on the 3f Icosa.

Dx G

Dick Fischbeck

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Jun 26, 2025, 1:23:11 AMJun 26
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Dx- Dome Times sure brings back the memories! I wonder if I have some copies laying around.  Thanks.
Dick

Levente Likhanecz

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Jun 26, 2025, 3:24:17 AMJun 26
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somewhere in this thread i attached a .dae extension file -- 3V K(2).dae -- (3V kruschke truncated below equator)
it is in collada format, and supposedly CAD programs can import such files, convert them to native types.

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