[HN Gopher] Geodesic domes made simple
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Geodesic domes made simple
Author : mooreds
Score : 156 points
Date : 2022-12-16 13:08 UTC (9 hours ago)
(HTM) web link (buildwithhubs.co.uk)
(TXT) w3m dump (buildwithhubs.co.uk)
| calebm wrote:
| Anyone know if these would work for hammocks (I wonder with
| wood). A friend of mine builds domes with metal, and I know
| people hang hammocks in them (which is a great system for giving
| a good number of people a place to sit or sleep). His dome
| website is here: https://www.edgedomes.com
| bilsbie wrote:
| How do you install the windows in this?
| hklgny wrote:
| If they're being really fancy, they'll create rough-ins for
| real windows embedded into the frame. But more commonly they'll
| just punch a hole in the exterior cloth and replace it with
| clear plastic. Here's some example photos if you're interested
| https://pacificdomes.com/domes-media-gallery/dome-homes-gall...
| FigmentEngine wrote:
| linux only i am afraid
| labria wrote:
| I'm sure NetBSD will be ported soon enough, if not yet...
| beefman wrote:
| Reminds me of the Starplate system. I lived in a Starplate dome
| for a few months in the late '90s.
|
| https://www.strombergschickens.com/blog/starplate-building-s...
| deepsun wrote:
| Looks even cooler, more space inside to stand.
| Communitivity wrote:
| Interesting idea. Something that made me pause was to see that
| each edge was attached via a single screw. People who know more
| about construction than me (majority of the world), isn't this a
| problem if you want a sturdy design?
| RobotToaster wrote:
| Also you're never really supposed to screw into end grain, it
| has half the strength of a normal screw joint.
| a9h74j wrote:
| Half-full or half-empty in this case?
|
| For end-grain I find estimates of 75% stength on average
| expecting considerable variation joint-to-joint, assuming
| proper pilot holes have been drilled. If the hold scales with
| the diameter of the screw, then a larger screw might
| compensate.
|
| The square of the wood's specific gravity might dominate
| differences:
|
| https://www.engineeringtoolbox.com/wood-screws-allowable-
| wit...
|
| Also, what is the pull-resistance on the snap joints
| themselves?
| traverseda wrote:
| Using a single screw turns that screw into a pivot point. For
| geodesic domes though the wood being able to pivot is not
| really a problem.
| jonathankoren wrote:
| Maybe not for the skeleton, but it's certainly a problem for
| the outer shell
| btbuildem wrote:
| Especially given that the screw is going into end-grain. That
| is a very weak joint, you could pull the screw out with pliers.
| foobarian wrote:
| It doesn't look like there are any pull forces in a dome so I
| wouldn't be concerned. Mainly there seems to be shear forces
| which could be a problem if the wood splits.
| JKCalhoun wrote:
| I don't know. Going into end grain I would want something
| with deep threads like a lag bolt. Given enough length
| (threads) it could be pretty solid.
| [deleted]
| [deleted]
| penneyd wrote:
| Is it possible (feasable) to create a geodesic dome on a hill or
| do you need a flat surface to make it work?
| otikik wrote:
| Yes it is possible.
|
| Main difference is that on a flat surface the dome weight is
| distributed across the base "automatically". If you just "copy-
| paste the default flat-terrain dome" on a sloped terrain, the
| bottom vertices might end up supporting more weight than the
| top ones. This might be ok for small/temporary domes. For
| something bigger/more permanent, you might want to "cut the
| sphere" in such a way that the weight distribution is as
| uniform as possible.
|
| Also keep in mind that even on a flat surface geodesic domes a
| foundation - for example so that they don't fly away when
| there's strong wind. This would go double in sloped terrain.
| analog31 wrote:
| You can do it on a hill. Draw one up, of your choice, and you
| will find that in some geometries, there are nearly straight
| arcs other than the equator. So you can remove portions, so
| long as you support the remaining intersections appropriately.
|
| (Note that I'm not an architect, but neither was Buckminster
| Fuller).
| benzofuran wrote:
| Anybody seen similar hardware out of aluminum or coated steel or
| stainless that's also readily USA-available? Machining these
| could be done on a small lathe and single-sided CNC...
| otikik wrote:
| You might want to try the Wranglerflange (I have not tried this
| myself)
|
| https://thewangerflangecompany.bigcartel.com
| somehnacct3757 wrote:
| I don't know about the metal portion of your question, but I
| ordered from the OP site just fine with a US shipping address
| leashless wrote:
| _much_ simpler: https://morganengel.com/nearodesic-polyhedron-
| hexayurt-dome-...
|
| No hubs, it's all 4x8 sheeting and long straight cuts. This one
| was taped together, but it could be plywood and screws as easily.
| otikik wrote:
| > The structure's use of tape makes it far from permanent. If
| you wanted to make this structure something more permanent-one
| man mentioned a hunting cabin in the snow-I'd definitely look
| into something more hardware-based. Something that used
| hinges/washers/bolts or the like to provide a lot more strength
| at the junctions
| rdtwo wrote:
| I don't really understand the geodome fascination. They aren't
| very space efficient structures because of all the low hight
| space at the perimeter that's difficult to use.
| a9h74j wrote:
| Seems like a reason to combine with knee-walls or posts, to
| make curved space be more overhead.
|
| Indeed, their gallery shows a good fraction of examples doing
| so.
|
| https://buildwithhubs.co.uk/gallery.html
| foobarian wrote:
| My problem is the covering. A more linear structure is a lot
| neater to cover with a tarp or clear plastic (say, for building
| a greenhouse).
| [deleted]
| snapetom wrote:
| I toured three in open houses while house hunting and
| considered putting in offers. While they can be interesting and
| pretty cool, you are spot on. They really are quite space
| inefficient.
|
| They feel nowhere near as big as their square footage listing.
| Our target square footage of 2500-3000 square feet required an
| equivalent of 4000 geodesic. The smallest one was 2700 and it
| felt downright tiny. Their round nature makes room partitioning
| awkward and unless you purposefully put ceilings on rooms at
| the top level, you're going to have situations where the master
| bedroom opens up to the kitchen via the roof.
| bilsbie wrote:
| You could put storage in the low places.
| 0_____0 wrote:
| As someone who has constructed a couple, I can attest that they
| can be a pain in the ass. They do get more efficient as you
| build larger ones, and they can pack down quite well (the
| covering for a soft shell dome is usually larger than the
| structure components). They are also wickedly strong once set
| up.
| photochemsyn wrote:
| Looks like a fun project but also illustrates why geodesic domes
| never caught on as a standard construction type: nodes/hubs or
| whatever you want to call them are a problem. Most standard
| construction joints have 90 or 45 degree angles, not the complex
| geometry found at a geodesic node. While initial construction is
| not that bad, maintenance and replacement over time (particularly
| with wooden structures) would be very difficult. All-steel
| construction of nodes and interconnecting beams, wih careful
| rust-resistant treatment, might be more viable, but that likely
| increases costs quite a bit.
| carapace wrote:
| They caught on for covering large areas (stadiums, aircraft
| hangars, etc.) but they don't really make sense on what you
| might call the "human scale", roughly 3 to 10 meters, say. At
| human scale wood and metal are strong and light enough that you
| don't really need geodesic designs. (Wood and metal are
| geodesic already, just at small scale, eh?)
|
| - - - -
|
| A slight tangent, but check out the demo carbon-fiber strut
| work here: https://dragonplate.com/carbon-fiber-truss
|
| > The truss measures 8 feet long, 16 inches high with a depth
| of 12 inches. This is just one of many structures that could be
| easily built using our square tubes and gussets. Weighing in at
| just 14lbs., the truss is light enough for a six year old child
| to lift and carry!
|
| They show that: a cute kid holding it up, no problem. Then they
| load it up.
|
| > ...we loaded it with 35 80lb. bags of concrete mixture,
| totaling a whopping weight of 2800 lbs.! Again, we saw no signs
| of weakness or flexing. We would have put on more bags, but we
| just couldn't stack them any higher!
|
| We could cover whole cities with domes...
| photochemsyn wrote:
| Those trusses look very solid. One back-burner research
| project of mine is synthesizing carbon fiber using
| atmospheric CO2 as the feedstock, it's fairly involved but
| plausible.
| carapace wrote:
| That sounds good!
| soperj wrote:
| > maintenance and replacement over time
|
| How much maintenance do you do on the wood in your current
| house?
| jonathankoren wrote:
| Fair point in abstract, but geodesic dome houses are
| notorious for leaking. Case in point, Bucky's house in
| Carbondale
|
| https://fullerdomehome.com/
| douchescript wrote:
| I have one of their kits. Pretty nice kit and fun to build.
| traverseda wrote:
| I think they need to release a 3D printable version. 3D printing
| is going to be more expensive and more fragile than injection
| molding, but being able to print a replacement ball connector or
| the like is one way this can become a lot more resilient, other
| than having multiple manufacturers. If they want to become
| something like a standard then having a work around for that kind
| of supply chain issue is important, I think.
|
| EDIT: They do appear to make "simplified" 3D models available for
| download from their hub-part-specs pdf. I suspect with a high
| layer height like 0.3mm you could print replacements. I
| understand why they don't advertise this though.
|
| https://buildwithhubs.co.uk/downloads/hubs-part-specs.pdf
|
| https://buildwithhubs.co.uk/downloads/hubs-cad-models.zip
| graeber_28927 wrote:
| Rather I think they should release a metal only version. I
| don't trust plastic to live a long and prosperous life in
| outside conditions, those are not where plastic shines.
|
| As for 3D printing, I guess ABS could work (PLA can melt or
| become soft in the sun), but I can't imagine a hobbist grade
| printer producing a part that is comparably strong. The option
| would still be nice, though. Maybe you just need a prop for the
| theater, where weather is a non-issue, and being able to
| replace parts quickly is more important than longevity.
| CarVac wrote:
| PETG is a better choice for outdoor use than PLA or ABS.
| traverseda wrote:
| You can definitely print strong enough parts, most 3D printer
| slicing software is optimized to reduce material cost not to
| create strong parts. Increasing the number of walls is a good
| place to start.
| malfist wrote:
| You want thermoplastics sitting out in the sun being part of
| the structural system of a building? That seems like a recipe
| for a building collapse.
| traverseda wrote:
| I think the term "building" is a bit of a stretch. Mostly the
| geodesic domes seem to be used as small greenhouses, and
| don't have enough weight that even a sudden collapse would
| really damage the occupants. The manual suggest that the
| maximum weight for the whole structure should be about 60kg.
| I'm not really concerned that these things aren't meeting
| fire code either, you know? You can just pick a wall and tear
| through it in almost all the examples I've seen in the
| gallery.
|
| That being said the glass transition point of ABS plastic is
| 105'c, a little over boiling. I'm not worried about ABS from
| a thermoplastic perspective, although I am worried about
| long-term UV performance. I'd also be worried about thermal
| cycles and plants/mold as most 3D printed ABS will take on
| water.
|
| I think you'd get a few years out of an ABS plastic component
| in these circumstances, more if you resin coat it or use
| acetone vapor smoothing, and start with a filament that has
| good UV resistance.
|
| Either way I expect 3D printed components to be more
| expensive and otherwise worse than one manufactured by this
| company, but being able to repair stuff like this if you need
| to is important and it's not like you can just go to the
| hardware store and get a replacement one of these hubs.
| chucksta wrote:
| Everyone always seems to overlook you can just paint the
| parts for UV protection
| traverseda wrote:
| I'm not sure how that would interact with the mating
| surfaces in this particular design, I suppose you could
| paint it after it's already in place though.
| ehnto wrote:
| There are entry-level consumer filaments that would withstand
| the UV and heat requirements for outdoor use, such as PETG
| which is UV stable and as strong as ABS.
|
| By entry-level I mean able to be printed on the everymans
| Ender 3, <$300 printer with little expertise. There are of
| course dozens of exotic filaments you can print on a slightly
| more advanced machine and even that can be done for pretty
| cheap, <$500 perhaps if you have the expertise to upgrade an
| Ender and tune it properly.
|
| The benefit injection molding has over printing in this case,
| is these parts might want to be redesigned to reduce sheering
| at the layer lines on the peg things.
| malfist wrote:
| UV stability is only one aspect. What happens when you
| build a greenhouse out of these and the temps reach high
| enough to deform these? How long do you think the structure
| will stay stable with or without UV paint?
|
| I've had a greenhouse melt nursery pots left in it and
| they're made out of polypropylene, which has a glass temp
| 50C higher than ABS.
| traverseda wrote:
| The inside of your greenhouse is reaching ~150 degrees
| celsius? Why aren't your plants boiling? Is it just a
| color thing?
|
| EDIT: the glass transition point of PP is -25C, vs ABS's
| 105c. I think you confused glass transition point with
| melting point, they're very different things. I think
| polypropylene will always be a bit soft, and will hold a
| shape that it's deformed into, it it hold that shape long
| enough.
| greyk47 wrote:
| I've definitely been drawn into the mysterious gravitational pull
| of geodesic domes. never built one, but as soon as I have a place
| to build one, I plan on it. I've looked at a lot of different
| ways to build one.
|
| the trillium domes that someone shared is definitely the 'nicest'
| version I've also seen loads of other 'hub' designs. personally I
| think zip tie domes are really interesting, seem the cheapest:
| https://www.ziptiedomes.com/geodesic-dome-hub-kits/index.htm
|
| but seeing this just gave me an idea for a really simple hub
| design that would potentially be more sturdy than these single
| screw attached, plastic socket hubs.
|
| what if the hub was simply a pentagonal puck of wood, and the
| spokes are attached with hinges? the complicated part of building
| domes is getting the angles right and using hinges mean you
| really only have to get the distribution of spokes around the hub
| right and the hinge will naturally fall into the correct angle?
| anyone got any land I can try to build this on?
| a9h74j wrote:
| Or pocket-screws in place of hinges?
| greyk47 wrote:
| sure but then you have to calculate the angle between each
| hub and spoke and cut the edges of the hub and boards to
| allow for flush angles when you screw them together. the
| whole idea behind the hinge is the angle will just naturally
| fall into place as you're building the structure.
| JKCalhoun wrote:
| A guy making geodesic domes _without_ hubs came up on my YT
| playlist recently. I went in skeptical, came away thinking this
| is the way I would go .. uh, you know, when I finally build my
| dome-abode.
|
| If you have woodworking skills (and table-saw, chop-saw), it
| looks like a no-brainer. For better or worse, the guy goes on a
| long time about the template/jig he creates -- its utility become
| obvious later when he begins to make the panels.
|
| https://youtu.be/Sl9fEp-27EM
| a9h74j wrote:
| Same for me with YT recommendations, but I had not watched yet.
| Bevelled long-cuts and mitres to produce nice joinery. Finish
| (stain) wood. Assemble pentagons and hexagons as units. Plans
| and details at:
|
| https://trilliumdomes.com/
| joneholland wrote:
| YouTube recommended this guy to me last week despite having
| never been interested in a dome. It's truly odd how the
| algorithm works.
| jacquesm wrote:
| That's beautiful. I'm going to watch the whole video. My main
| interest is the sealing problem between the individual panels
| which seems to be an issue with almost any dome build except
| for the inflatables.
|
| I've built on with hubs and it worked ok, we used thin plastic
| to cover it overlapping two panels on the horizontal seams but
| that is rather wasteful in material and allows less light in.
| bccdee wrote:
| Seems like you could use a silicone caulk or something.
| JKCalhoun wrote:
| Even backer-rod compressed between the panels would help.
| jacquesm wrote:
| Yes, that's one possibility. One elegant way to do that
| would be to route a groove in the cross members and then
| to stick the seal in there. This still leaves a bit of a
| problem with standing water in that groove and frost.
| jacquesm wrote:
| Sure, but it's a lot of seams, 100's of meters on even a
| moderate size dome, they are very deep (typically about 2"
| or 5 cm) and it add an enormous amount of work to setting
| up a dome. It also means you can no longer take it apart.
| [deleted]
| dugmartin wrote:
| I came here to recommend the same video. Its is a very
| interesting design. I think an cool application would be to
| build this first using semi-opaque greenhouse panels and then
| building a cabin within the dome.
| JKCalhoun wrote:
| I like that. It allows the interior cabin to be "open". The
| Jetsons meet the Waltons.
| DonHopkins wrote:
| But I thought Hexagons were the Bestagons! ;)
|
| https://www.youtube.com/watch?v=thOifuHs6eY
|
| Hexagons, Pentagons, and Geodesic Domes
|
| http://mathtourist.blogspot.com/2010/06/hexagons-pentagons-a...
|
| Introduction to Hexagonal Geodesic Domes
|
| https://www.hexdome.com/introduction/index.php
| jacknews wrote:
| Not meaning to poop on anyones parade, but 'stardomes' make more
| sense at this scale IMHO, http://www.stardome.jp/index-en.html
| Mountain_Skies wrote:
| Reminds me of playground equipment of a similar design, though
| I think that was a hemisphere design and may have used straight
| pieces with bent connectors that connected in the star pattern.
| UniverseHacker wrote:
| That is amazing! A true example of inspiration by Fuller...
| these people get it. Instead of writing yet another useless
| "thinkpiece" about the limitations of Fullers ideas, they were
| inspired to do even more with even less!
|
| Edit: this idea could be easily executed with carbon tent poles
| and a nice waterproofed canvas tarp over the top. A portable,
| easy to build and durable DIY building more substantial than a
| nylon tent.
| otikik wrote:
| I think curved lines like the stardomes' make sense and have
| some very interesting advantages. The "hubs", which tend to
| concentrate complexity and cost on "flat line doms", are
| simplified, disappearing in some cases.
|
| There's some disadvantages though. A flexible structure is not
| always desirable. Bamboo (or an equivalent replacement) isn't
| available everywhere. Also, flat-line domes are easier to cover
| with flat inflexible materials like wood panels. In short: if
| you have access to Home Depot and no access to bamboo, flats
| might be easier for you to build.
| red_trumpet wrote:
| And they feature real geodesics[1]! I was a bit confused why
| the geodesic dome has it's name.
|
| [1] https://en.wikipedia.org/wiki/Geodesic?wprov=sfla1
| el_nahual wrote:
| The stardome reminds me of the Boyne Coracle, a small
| rudderless raft made of willow and ox hide. Here's a video from
| 1935 showing its construction:
| https://www.youtube.com/watch?v=aCWFDMnKLyM
| jacknews wrote:
| Except the 'stardome' has some mathematical underpinning,
| rather than being just 'wattle and daub' or 'skin on frame'
| for domes, etc.
| justinator wrote:
| My art professor lived in a geodesic dome commune in the southern
| Colorado. Also discovered aperiodic tiling before Penrose who
| still sued him (and lost).
| XOMDOM wrote:
| I actually am building one of these but not from wood I purchased
| a dome home kit from pacific domes one of the first company's to
| develop the dome from its originators idea
| DOMSWOOZ wrote:
| I actually am building one of these but not from wood I purchased
| a dome home kit from pacific domes one of the first company's to
| develop the dome from its originators idea
| liminal wrote:
| These hubs look like they can greatly simplify geodesic dome
| construction. Lots of people here are commenting on the longevity
| of plastic or alternatives to geodesic domes, but I think that
| misses the point. Nothing is perfect for every application, but
| this looks perfect for getting a dome up quickly and easily.
| teleforce wrote:
| Several years back I was thinking about the ideal shape of
| solar panels, and concluded that the best is the geodesic dome
| shaped structure. This shape will have the optimum sunlight
| exposure regardless of the location of the sun during the day.
| bitxbitxbitcoin wrote:
| Optimum sunlight exposure in terms of longest duration of
| exposure but I don't think that would be the optimum in terms
| of charge generated.
| hedora wrote:
| Things get interesting when you start minimizing the total
| system cost of the solar panels + batteries. Household
| power usage peaks at dusk and dawn.
|
| In on extreme, you can either aim panels for optimal daily
| production (minimizing panel count) and buy more batteries,
| or aim extra panels at the horizon so that you don't have
| to store as much electricity for peak times (minimizing
| battery count).
|
| In practice, something in between the two extremes probably
| makes the most sense, though most installers err toward
| minimizing panel count these days.
| [deleted]
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