HEXAGON/PENTAGON based Prefab/Modular style domes?

[Erich Nolan Bertussi]

Hey all,

I am curious about whom if anyone out here is yet building hexagons and the few pentagons needed as prefabricated sections for modular dome building. 

I might not be using the correct terminology and thusly I am unable to locate any data regarding such endeavours.

If anyone is aware of any projects please do let me know, I am eager to see whom/what is being done in that vein of approach to delivery of final solutions. 

Thank you all kindly for helping me on my geodesic dome journey. 

cheers..

ENB..//

[Levente Likhanecz]

hi Eric,
https://3dwarehouse.sketchup.com/model/800b4604-e846-4d3c-a3e8-427c11f0e32e/hexagon-dome
if you are familiar with sketchup software.
the design is from few good people aronud here i just drawn it.

[Gerry in Quebec]

Hello Erich,

If you provide more details on what you'd like to build -- such as dome size, function and climate -- you might get several more detailed responses such as the one Lev posted about Chris Kitrick's design. 

There are quite a few searchable conversations and document attachments within this Google discussion group. One useful search term is "hex-pent". You might also try: greenhouse, Goldberg, Goldberg polyhedron, I(2,2), truncated icosahedron, Buckyball, Eden Project, and Montreal Biosphere.

Good luck.

- Gerry in Québec

[Levente Likhanecz]

hi Gerry,
thanx for the reminder, that it was Chris'es design. i was soooo lazy
to search for the original thread. i recall that Adrian supplied then
the proper parametering for antiprism to calculate them quickly,
something canonical-non canonical double geo models.
it looks like i can't avoid some timetravel in my mailbox.

cheers, lev

[Paul Kranz]

There's also Fuller's Hexa-Pent Dome published in Popular Science. Paul sends...

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[Gerry in Quebec]

Here's an example of a possible hex-pent or "honeycomb" dome design:

 -- Hemisphere with a flat base

 -- 67 planar faces including the floor: 6 red pentagons, 30 yellow hexagons, 10 green hexagons, 10 blue hexagons, 10 blue half-hexagons, and the footprint or floor which is an irregular 20-sided polygon. 

 -- Pentagons are regular; hexagons and half-hexagons are irregular.

 -- 20-sided footprint (floor) with 2 different side lengths.

  -- 3 slightly differing radius lengths

  -- 6 chord lengths including the long horizontal base struts. 

 -- 195 edges

 -- 130 vertices

Triangulating this honeycomb structure would add 4 new chord factors, for a total of 10 (including the long base struts in the honeycomb framework), as well as 2 new radius lengths, for a total of 5.

- Gerry in Québec

On Sunday, September 5, 2021 at 10:15:32 PM UTC-4 Erich Nolan Bertussi wrote:

[lemondealc]

What are you trying to accomplish? Or are you just curious?

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[Gerry in Quebec]

Lovely design, Rob, with an interesting connection system. Looks really practical.

One way to make a hex-pent structure of this topology, and with only three strut lengths, would be to exploit the Clinton Conjecture, specifically Goldberg tessellation I {2,2}. With that "sphere" all the vertices are equidistant from the spherical centre and all edges are the same length. However, there are two potential problems using this geometry to build a dome. First, the equator undulates a wee bit. But if you make a slight adjustment to the locations of 10 of the 20 vertices defining the dome footprint, you end up with a flat base. This introduces two new strut lengths for a total of three. The second problem is that most or all of the hexagons in the hex-pent structure are not completely flat. So if you want to use a rigid material for the dome roof, you might run into problems of twisting, However, a material like ETFE, the plastic pillows used in the Eden Project in England, would probably be forgiiving enough to deal with the slight lack of planarity of the hexagons.

 Is it possible that this 3-strut hex-pent dome is exactly the one in your images? Or did you find another solution?

Cheers,

- Gerry in Québec

On Saturday, September 11, 2021 at 9:38:46 PM UTC-4 clark.rob...@gmail.com wrote:

Gerry,

It is possible to construct a hex-pent dome with only 3 chord lengths.  This one uses just 3 struts and 6 brackets of varying angles.

[Erich Nolan Bertussi]

wow LIkh, that is pretty awesome thanks so much!

[Erich Nolan Bertussi]

Hey Gerry,

I'm hoping to deploy north of Saguenay! so the plan is to prefab all the hexagons using hemp and bamboo lam and make the walls a nice 30" + thick (just like good old Ville de Quebec 1700s walls!)

thank you so much for the hex-pent term! awesome!! and goldberg etc.. I would love to connect if you ever find your self in the Montcalm quatier of Ville de Quebec.. 

[Erich Nolan Bertussi]

I recently found this website and they seem to have figured out some of the math on a geodesic dome made of hexagons and pentagons.. the question is how do i find the math to sort out how big everything is so i can mock it up in sketch up and start focussing on the details of each modular hex wall/roof/dome panel.. 

found this on a Romanian website https://www.biodomes.eu/

[Dick Fischbeck]

Hi Erich- Read Joe Clinton's conjecture:

http://www.domerama.com/technical/clintons-equal-central-angle-conjecture/

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[Erich Nolan Bertussi]

Thanks Dick, that is a totally awesome post !  

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Erich Nolan Bertussi

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https://clearexpanse.ca/

[Erich Nolan Bertussi]

OMG Clark, this is pretty much where my brain is at right now.. time to build good old architecture school cardboard mockups stat.. lol 

On Tue, 25 Jan 2022 at 22:00, clark.rob...@gmail.com <clark.rob...@gmail.com> wrote:

Also, Goldberg polyhedrons

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[Ashok Mathur]

You can shrink the inventory considerably if you treat sides that differs by say 1% as being identical.

When you do that the dome will wrap slightly from a true dome, but anyway geodesic domes reside on the sphere surface only at the vertex.

Let us try it mathematically.

Regards

Ashok

Sent from my iPhone

On 30-Jan-2022, at 3:29 AM, Erich Nolan Bertussi <er...@clearexpanse.ca> wrote:



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[Erich Nolan Bertussi]

wow, Clark this is incredible.. so this 3d render you have here is utilising those identical off centre hexes shown in the 2d drawing? 

On Sunday, January 30, 2022 at 8:52:44 AM UTC-5 clark.rob...@gmail.com wrote:

I've been playing with the Goldberg polyhedron used for the  Carnegie Mellon's Panoptic Studio.  It is a chiral polyhedron and there would be some special cut shapes at the base, but what I like about it is that all the hexagons are identical.  There would be 40 full hexagons.  There are 5 "half" hexagons and 5 "half pentagons at the base.

I've created a design pattern that could be used for a 14-1/2 foot diameter greenhouse dome.  The panels are constructed of 2x4 lumber split down the middle with a table saw to get the dihedral angle.  Gussets at each corner (top side and bottom side) would be cut from 1/2 inch plywood using a band saw.  There are rectangular strips between the gussets so that the sheet plastic can sit flat.  Gussets are glued and screwed to top and bottom.  Panel frames would get a generous coat of polyurethane waterproofing.

-Robert

There are two dihedral angles of 153.18 degrees (between hexagon panels) and 156.76 degrees (between hexagon and pentagon panels).  To simplify construction, I would have the angle cut for the pentagon at 9.83 degrees all around.  And, for the hexagon it would be 13.41 degrees all around.

[Erich Nolan Bertussi]

Hey Ashok,

Ya i'm not completely concerned about how 'curvy' they are really. i think for 'tiny domes' i'd use the soccer ball lay out for homeless housing solution so i'm not too concerned at all about how pointy it ends up being.. 

[Erich Nolan Bertussi]

Hey Ashok,

Ya i'm not completely concerned about how 'curvy' they are really. i think for 'tiny domes' i'd use the soccer ball lay out for homeless housing solution so i'm not too concerned at all about how pointy it ends up being.. 

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[Dick Fischbeck]

I think you are right. Therefore, you can build a large dome or sphere with a few pieces.

How do we keep out the rain? Lots of seams.

On Sat, Jan 29, 2022 at 4:58 PM Erich Nolan Bertussi <er...@bertussi.ca> wrote:

Do the goldberg polyhedrons or 'cages' in these images i am finding on the subject then indicate by colour coding that there are identical sized hexagons or pentagons given each colour used? am i understanding this correctly? Clark?

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[Erich Nolan Bertussi]

wow, Clark this is incredible.. so this 3d render you have here is utilising those identical off centre hexes shown in the 2d drawing? 

On Sun, 30 Jan 2022 at 08:52, clark.rob...@gmail.com <clark.rob...@gmail.com> wrote:

I've been playing with the Goldberg polyhedron used for the  Carnegie Mellon's Panoptic Studio.  It is a chiral polyhedron and there would be some special cut shapes at the base, but what I like about it is that all the hexagons are identical.  There would be 40 full hexagons.  There are 5 "half" hexagons and 5 "half pentagons at the base.

I've created a design pattern that could be used for a 14-1/2 foot diameter greenhouse dome.  The panels are constructed of 2x4 lumber split down the middle with a table saw to get the dihedral angle.  Gussets at each corner (top side and bottom side) would be cut from 1/2 inch plywood using a band saw.  There are rectangular strips between the gussets so that the sheet plastic can sit flat.  Gussets are glued and screwed to top and bottom.  Panel frames would get a generous coat of polyurethane waterproofing.

-Robert

There are two dihedral angles of 153.18 degrees (between hexagon panels) and 156.76 degrees (between hexagon and pentagon panels).  To simplify construction, I would have the angle cut for the pentagon at 9.83 degrees all around.  And, for the hexagon it would be 13.41 degrees all around.

To view this discussion on the web visit https://groups.google.com/d/msgid/geodesichelp/fcd563ca-05e7-4874-aa06-233da26cb5dbn%40googlegroups.com.

[Erich Nolan Bertussi]

My expectation about keeping out rain is a tight fitted 3d printed rubberised hemp gasket. between hexes/pents as well as for exterior panels/exterior finish.. 

On Thursday, 3 February 2022 at 19:37:52 UTC-5 clark.rob...@gmail.com wrote:

Yes.

[Erich Nolan Bertussi]

Wow Robert this is incredible... I guess I should start printing out some scale models on paper and building something eh..

How did you sort this math out? 

Any ideas about how i could implement my max 4'x4' hex or pent idea.. with various sizes of dome diameters? 

On Thursday, 3 February 2022 at 19:37:52 UTC-5 clark.rob...@gmail.com wrote:

Yes.

[Erich Nolan Bertussi]

Since I am going for r100+ walls as prefabricated max 4' x 4' by 30"36"+ thick wall sections with each hex bolted to the next I need to figure out a gasket solution for the seems 100% no choice.. but hopefully using hex's will provide less demand of total seem length than building 6 triangles inside of each hex might demand.. although i would be able to make larger triangles... 

The goal is to minimize parts and maximize repetition to make premanufacturing internal components of each hex wall section more rapid and less onerous in terms of different components.. 

I'll check out solidworks too, which package do you use ? I have no budget yet... 

I will check VikingDome for sure... looks like similar maths.... do you know if they are using identical hexes as you have in your sample drawing?

thanks so much for your help/guidance/and mentorship, as I dip into the world of dome design and principals.. I really appreciate it very much Robert...

:) 

On Fri, 4 Feb 2022 at 15:59, clark.rob...@gmail.com <clark.rob...@gmail.com> wrote:

You might want to look at the Aura Dome by VikingDome.  Their domes are made from overlapping hexagons of clear plexiglass.  By overlapping, they shed the water off and don't have to worry too much about water infiltration - except from strong wind driven rain.

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[Erich Nolan Bertussi]

Hey Robert, 

I was building passivhaus style homes (very very beyond r2000 back in the day) in Ontario Canada as luxury homes with German born luxury home builders in the mid 1980s, uncles of mine on two sides of my mothers family... we imported quad and 5 glaze windows from germany and used double wall construction for exterior walls that were always at least 24" thick. ground source heat pumps for heated floors even solar panels on the roof in the 1980s... 

So I have a different perspective on 'returns' for insulation, and don't expect there to be stability in energy costs given current global driving forces..

the objective is to make these domes as tight and insulated as is possible.. OFF GRID ready, or 'grid collapse prepared' and we aim to use as many renewable materials as possible including hemp-wool based insulation as well..  I don't want them to require anything much more than a blow dryer worth of energy to heat but will prefer to implement thermal mass for winter solar gain storage as well in the form of TROMBE wall type technology.. 

I would like a typical dome to be able to accommodate growing of food internally too, (similar to Mike Reynolds is doing in New Mexico with his earth ship project)  

The window maker we're hoping to work with in BC, is 'innotech & widows and doors' and I have to say they have outdone the Germans when it comes to approaching how to make windows for passivhaus standards.. https://www.youtube.com/watch?v=_vul4vMFdkA check out this video for their amazing envelope design/passiv window technology.. 

this is where my head is at.. super ultra passiv for not alone implementing off grid, but surviving a time when maybe the grid doesn't come back up.. ;) 

On Friday, 4 February 2022 at 17:33:24 UTC-5 clark.rob...@gmail.com wrote:

Erich,

VikingDome is not using all the same hexagons.  I'd have to look at their model again, but I would guess that it's at least 4 different hexagons.

Increasing insulation thickness will give give you diminishing returns vs increased cost.  I think I've read that once you are over R40, you are not gaining very much for the increased cost.  A one foot thick wall of styrofoam will probably give you close to 60R-value.

What will be the interior diameter of the dome?  What will be the insulation type?

best regards,

Robert

[TaffGoch]

On Fri, Feb 4, 2022 at 3:09 PM Rob Clark wrote:
"The frameless Aura Dome by VikingDome..."

 Depiction of the 3D geometry (modeled in SketchUp):

-Taff

(aka, David Price)

[Sh Mc]

I can speak to specifics in regards to insulation as I used to work in the commercial and residential business of insulation. I'm from North East Ohio and it gets below 0 and sometimes well into the -30 wind chill factor living near Lake Erie (snow belt). For ceilling insulation it is required to be R38. And Exterior walls should be atleast R14 but typically R24 in newer construction. Packing R100 will give you some mighty thick panels even insulated concrete forms do not get R100. Spray foam is the best hands down (Unless you plan to make a lot of aerogel). It is an R3.5- R3.6 per inch. Which means your panel without knowing how you plan to finish the panels inside and out are going to be around 24-30 inches thick. The best insulated homes I've worked in were R40 in ceilings (typically blown in fiberglass insulation.)  I would consider the entire dome structure save for a stem wall. 

Sent from my T-Mobile 4G LTE Device
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From: geodes...@googlegroups.com <geodes...@googlegroups.com> on behalf of clark.rob...@gmail.com <clark.rob...@gmail.com>
Sent: Friday, February 4, 2022 3:33:24 PM
To: Geodesic Help Group <geodes...@googlegroups.com>
Subject: Re: HEXAGON/PENTAGON based Prefab/Modular style domes?

 

Erich,

VikingDome is not using all the same hexagons.  I'd have to look at their model again, but I would guess that it's at least 4 different hexagons.

Increasing insulation thickness will give give you diminishing returns vs increased cost.  I think I've read that once you are over R40, you are not gaining very much for the increased cost.  A one foot thick wall of styrofoam will probably give you close to 60R-value.

What will be the interior diameter of the dome?  What will be the insulation type?

best regards,

Robert

To view this discussion on the web visit https://groups.google.com/d/msgid/geodesichelp/c7365b82-3aab-4179-a7c2-22c6c388f423n%40googlegroups.com.

[Erich Nolan Bertussi]

Hey there, Sh Mc.

I have always expected each truncated hexagonal/pentagonal wall module to be about 26"-32" deep to ensure I could fill it with either hemp insulation or if such exists an eco-spray-foam.

The way the dome wall modules were revealed to me will end up creating two monolithic foam domes inside the walls since there are two gaps from the interior wall to the exterior wall this 'monolithic' belief of course would only more truly exist in a spray foam type deployment... 

My partner is more attracted to the auspices of hemp-wool, but I am more determined to achieve maximum R value, beyond what any regulatory or guiding body would mandate with building code.

The aim is to ensure that as little energy to heat and cool is required up to +45C and -45C and of course while supporting 10 feet worth of wet snow accumulating on the dome too.