Geodesic domes are light, strong structures with huge interior space that is very pleasant and inviting.  Unfortunately they tend to take many man-hours to erect.  I wanted a dome that could be easily put up by one or two people in short order. Hence the Folding Geodesic Dome, also known as the Democracy Dome since it's made from recycled political campaign signs.  With another election coming we may get some new raw materials soon...  Unfortunately this concept is not yet strong and windproof enough for the desert, but testing is underway for a more secure way to attach the segments.  More on this later in the Instructable.

It takes 105 triangles to make the particular dome shape I wanted (called a 3V), which could be a time-burner to assemble.  The Folding Geodesic Dome simplifies things  with tape hinges that pre-connect many of the triangles into 16 segments, each of which can fold into a small stack and connects to its neighbors via tabs and clips. The more hinges used the less time spent connecting triangles in the field.  The dome goes up with 2 people in 2 hours or less. Takedown time is 30 minutes.

There are great Instructables for light domes made from coroplast or cardboard which negate the need for a support frame. This dome was made with an eye for economy, using 20 surplus 4’x8’ 4mm coroplast political campain signs found on Craigslist for $100.  The panels can be made from any stiff material  (cardboard, coroplast, thin plywood, plexiglass) that is rigid enough to resist bowing.

This project was made possible by the resources at desertdomes.com including their dome calculator, dome formulas and the dome diagram that I use in this Instructable. (If you build a dome, please donate to desertdomes.com as I did.)

This dome is a light-duty ‘backyard’ dome, done as a proof-of-concept; it isnt’t waterproof or windproof enough for open country yet.  My next version will utilize a combination of thin plywood for the hexagons and coroplast for the pentagons (to let light in) and will address weatherproofing.  This project was a runner-up in the ShopBot Contest - most exciting!  Thanks to everyone who took the time to vote.

Step 1: Design

A “3V” geodesic or polyhedral dome is made of hexagons and pentagons, which means you will need 2 basic triangle shapes, called BAA and BCC. Start your project with a visit to desertdomes.com, where you will find dome diagrams, dome formulas and an invaluable dome calculator.  This Instructable is for a dome with a 7’ radius; this is a “5/8” 3V dome meaning taller vs flatter, over 8’ tall in the middle. The dome likes a flat surface to sit on making it ideal for the open desert playa, not so suitable for uneven terrain. The dome base isn't exactly flat, but close; the flexible nature of the coroplast bows and yields a little when you deploy it to make up for any uneven contact (Note:  the prototype pictured here has a radius of 7.2’ but wasted more material from a 4x8 sheet. My next dome and this Instructable use the dimensions for an 84” radius - 7')

The dome is composed of 3 basic folding segments: a pentagon (5 triangles), a hexagon (6 triangles) and a “hexagon plus 3” (9 triangles for the base row ).  Each segment unfolds and is clipped into a convex shape with binder clips or a clamp made from pvc pipe. 

To calculate the dimensions of the 2 triangles (BAA and BCC), use the desertdomes.com dome calculator and enter the dome radius in inches to get get the lengths of the A, B and C triangle sides. 

For the radius of 84” (7 feet)  we get
A= 29.284”  (roughly 29 1/8”)
B= 33.898” (roughly  33 7/8”)
C= 34.642” (roughly  34 5/8”)

I used those numbers to calculate:
Height of BAA =  23.881” (roughly  23 7/8”)
Height of BCC= 30.213” (roughly  30 1/4”)
.5xB = 16.949” (roughly 16 15/16”, for the midpoint of the B edge)

For the 3V, there are 30 “BAA” triangles (to make 6 pentagons) and 75 “BCC” triangles (to make 10 hexagons and 5 semi-hexagons).   1” wide tabs are placed along B edges to connect segments together, and on some of the C and A sections too.  The triangles along the base of the dome have 4” tabs with holes for the anchor stakes.  Edges that don’t have tabs will have tape hinges that connect to their neighbors.  I’ve mapped out where the tabs need to be for every triangle needed in the dome, adding up to 12 different shapes you’ll cut - download the pdf Cutlist for shapes and quantities.
Just an idea i had looking at this, you could glue Mylar onto the panels and wrap duct-tape around the edges to make it weather resistant. It woukd help keep the heat from the sun off too.
16' coroplast 4V dome. assembling , thank u for much , still ran into a lot of walls, more pics coming...
<p>Wow - that looks great! I can be slow in responding to my Instructables comments, but please keep me updated on your progress. I just did a build in my backyard of the folding dome, and will update my Instructable with some picks. I've updated the design w some holes in the tabs, allowing zip-ties to keep it tight against the wind. I've also figure out an easy way to make it sit flat on the ground, as the 3v normally has 5 low-spots. Thanks.</p>
finally finished duct taping, steaming the tape helps alot, u get a roll of evenly heat duct tape, goes on really nice even cold, good adhesion , but there have been a few spots that are leaking and I found that great stuff injected from inside into the flanged flutes creates the most amazing results. the foam expands goes in and around creating seals and connections across the abut ed triangles, also used a dab of foam at every intersection, very pleased with results. if I have to move the dabs will pluck right out with little effort just using my hands, the triangles can be separated by cutting zip ties from inside and cutting the tape down the middle of the flanged triangle edges there by separating the tape and the foamed flanges. Also the foam has transfered into the triangle itself creating air locked chambers in the fluting of the triangles. Add a Carbonite window and a small plexiglass one just under it on the south side. inside I have started to use what I can find from trash to insulate, like cardboard, foam sign, coraplast , foam packaging, bubble rap. still need to put the 2' knee wall in and a door that will have a foyer. the 5/8 3V Dome u built didn't need a knee wall cause it's 5/8 of a Dome and this is a 4V dome , which is exactly 1/2 a sphere. So a ladder I can see is a must for a 3V 5/8 Dome. your dome is 2' taller than my 4V and required less triangles, so I can see why alot of 3 Vs are made. I'm a lover of triangles though...The wood stove works well with coraplast a small amount of shielding and to my great surprise , even with knowledge that this stuff is heat resistant it has yet to combust...
Still working at the kinks. There is alot of moisture build up from my own body, it builds on the ceiling triangles , freezes in the night then rains down when the dome heats up, I knew Coraplast is non breathing ,but there's got to be a way to create a breathable dome that still holds its heat?
<p>Maybe you can exchange air depending on moisture content in the air. But air loss = heat loss. Perhaps you are also getting moisture from the fire. </p>
<p>When I build it over my lawn, it's a wet mess inside from morning condensation. In the desert it's fine, as you might expect. I've put a tarp down first and pegged the dome onto it, and it was a lot dryer. The moisture from breathing is a tough issue though... Maybe one of your insulation linings might prove good at wicking/drying during the night/day.</p>
it's in the 30's and duct tape , even gorilla tape is hardly sticking... have learned alot... coraplast is very forgiving, but it's tricky on some cuts that run parallel to the fluting, it changes the location of the bending flange... I did all the triangles with flanges, alot of work... kind of wish I had made u r design, I was working on inserting wire into the triangles and adjoining them together with bent wire, it was way to hard and time consuming and winter is on my heels...I did make the roof separate and pulled it onto the top. I did all this solo...1st dome...could go on about mishaps and unpredictables but I'm still busy and all I got is a tablet...
<p>Better idea than plywood: Start with cardboard, soak in fiberglass resin and spray with waterproof fixative. Lightweight, crazy strong, definitely weatherproof. Heavy aluminum tape works great for joints. I suggest a layer of low-glare marine paint (so rainwater rolls off easily) but that's just me.</p>
<p>Wow - great idea! I have been looking at various commercial architectural panels, but they're expensive. Love the idea of strong waterproof cardboard. As for magnets, I've tried some rare-earth magnets on the tabs, but not enough strength as far as I can tell. Currently using reusable/removable zip-ties to secure the panel tabs, which is the strongest cheapo solution so far.</p>
<p>Also, magnetic joints? Love this whole concept, I must say.</p>
<p>Many thanks for sharing your creativity with the rest of the world, occupy indeed !</p><p>I would love to make one, but i have an important question, is it possible to erect it from the top down rather the other way round, negating the need for a ladder perhaps</p>
I just built mine and didn't use a ladder just a single milk crate for a little step up. the ladder in my pictures I never used... I too thought I would need one, but I did it buy building the roof separate and dragging it up over the outside walls, like pulling covers over head in bed, it worked, and it was close, somethings u have to think about, leave a section out on the wall so u can reach over the edge to pull up and over the roof.
<p>Do you have a quick way of calculating the number of triangles given a diameter?</p>
<p>The number of triangles stays the same, they just change in size. This page http://www.desertdomes.com/domecalc.html shows the various &quot;frequencies&quot; of domes. I built a 3v, 105 triangles I think...</p>
Cool idea I've seen homes in the Bay Area that look like that, and i've always admired them.
<p>wow, cool! :)</p>
<p>Bob, </p><p>I love your folding &quot;Democracy Dome&quot;!</p><p>Is there a way that you might be able to upload a Sketchup model of it to Google's 3D Sketchup warehouse?</p><p>Later this month, we'll be doing a demo of a 3D printer at a local school <br>in the Shenandoah Valley &ndash; and would like to be able to print out some scale models of your design. (I'll be delighted to send one to you if we can find someone to help in preparing the Sketchup model.) </p><p>After the school workshop, we'll launch an Kickstarter campaign to fund construction of an actual <br> popup dome along the lines you've set out, as a venue for ongoing 3D printing &quot;learning labs&quot;. </p><p>In the <br>course of doing research on affordable domes, we've found two links that may enable your coroplast sign dome to overcome wind and rain challenges, and make it <br>easier for people to enter and exit.</p><p>The wind/rain problem might be resolved with an overlay of burlap soaked in about $200 worth of this remarkable thinset cement: <br></p><p></p><p>http://www.instructables.com/community/Ever-heard-of-Ceramicrete-MgO-cement-Magnesium-c/</p><p>And the access could be made easier by including a playwood hexagonal base such as the following:</p><p>http://www.worldwidetelescope.org/docs/WorldWideTelescopePlanetarium.html </p><p>I <br> hope these links may help. We're excited at the prospect of using your <br>innovative design to help awaken interest in 3D printing and other <br>makerspace opportunities. Look forward to any comments and suggestions <br>on moving ahead!</p><p>Mark Frazier (mfrazier@openworld.com)</p>
Just worked out that what you call Coroplast is called Coreflute in Australia
another thing is can you just cut same size triangles and connect them and not do the math to do it. i also want it to have a radius of 5.5 ft so i don't understand how to figure it out because the website is confusing and also how to connect them i don't understand <br>
Hi is there anyway you can make it without the political signs(such as another material) if so what do you suggest. i would like to take it camping with me! thanks! <br>
She's a beauty, always been a huge fan of domes! Looks to be a lot less time on setup than a yurt and more travel friendly! I was trying to count how many pieces of pvc pipe one would need to join every tab? I got to 49 for sure and then maybe 60 total? Oh and would the structure support a tarp tossed over in case of rain? Thanks!
Just counted again, 60 tab connections it is. The dome would easily hold a tarp over the top, though flapping could be an issue unless well secured. <br><br>I also like a &quot;flying&quot; tarp suspended over my tents, keeping 99% of the water off the tent. When kept taught they won't flap in the wind too bad. If no trees available to suspend one, I use 8&quot; tall garden/tree support poles to hold up the corners. A 10' pole would clear the top of the dome pretty well I think.<br><br>Thanks for the comment!
Beautiful dome project! Is there anything in the deployment that prevents it from being assembled top-down, instead of bottom-up? I wonder if that would lend to less fighting with the support poles.
I think there's a good argument for top-down, but haven't tried it yet. I've worked on an assumption that much of the dome's strength comes from the lowest tier being directly attached to the earth, creating the perfect &quot;floor&quot; for the dome and giving rigidity. Yet it's quite floppy till you get most of it up, so maybe starting with the structure first and tacking it down later might work.<br><br>If you built it with the tabs on the outside for a smooth interior, you would need to build it top-down to reach the tabs on the upper segments.<br><br>The poles get easier after a couple of runs, but it can be pretty comical to move one thing and have them all try to fall on you.
Excellent! I'll give it a shot and report back, I'm building one for a regional burn in Colorado.<br><br>Have you found any other materials that would lend to waterproofing? A campmate built a hexayurt out of insulating panels last year, I'm wondering if that might be a path to investigate; though I wonder how well the tabs would stay attached once scored, even with a strong tape.<br><br>As for the seams... short of adding an extra layer of waterproof tape on the outside, that's a tricky one. There's always Great Stuff, but man, that stuff is a pain, and not ideal for repeated setup/teardown.
I think that I've got a fair solution to waterproofing. I'm going to tape all of the tab-hinges to seal the open flutes that get exposed when one face of the coroplast is cut. This should also add friction to the face of the tabs. Along with some of the tack spray mentioned in these comments, it should seal the tab connections well and add strength.<br><br>I'll take some pics and update this Instructable to show the method. I'm going to the desert first week of May and will be setting up the dome for another trial, so I'll include some pics of that as well.<br><br>Send some pics of your project!
I noticed you used what looks like lengths of PVC pipe for clamps to hold the pieces together. Am I seeing that right?
Yes, there is a pic of one (on the materials page I think) showing a lengthwise slit with notches at each end to help get the tube clamp onto the tabs. This gives more linear 'clamp' to the tabs. This along with using tack spray on the tab faces should make it strong enough for bigger winds.
Ok, that looks like a great clamping method, however, it seems like it would be annoying to slot all of that PVC. How did you do that? I am thinking of putting grommets on my tabs and using small bolts.
That would be plenty strong. I've even thought about taking out a big stapler to tack the tabs into place, and the proper staple remover for take-down time.
If you made one of these out of a clear material, it would make an outstanding greenhouse/cold frame for starting the garden earlier in the spring. :D
I'd like to make one out of one-way mirror plexiglass - shiny outside, unobstructed view inside. Reverse at night though I guess....
Kind of like those <a href="#" rel="nofollow">public toilets in London</a>? :D
Awesome!!!<br> <br> I am definitely building one of these to use a a temporary/portable gazebo...I will probably do a 2v Icosahedron though to decrease setup time.<br> <br> Having worked with these before do you think this setup would be stable or should i just do a smaller door like what you have? The final build will be 8 feet tall and built out of the same material you used. Also, how stable is yours without the poles?<br> <br> Thanks!
That's nice big door! The structure loses integrity when you lose triangles, which is a drawback to using a panel-based structure. I find that my dome gets a little 'saggy' around the doorway, so using just 2 poles to give the doorway some support really helps. <br><br>The door in your pic looks awesome, but I think coroplast wouldn't hold it's shape with that big a hole. The dome is somewhat floppy as you build it, getting firmer as you add segments; losing this much support may be trouble. Using a stiffer material like plywood might change that.<br><br>Perhaps get some free cardboard and build one out of that as a testbed, then use your findings to make the final one from plastic.
Yeah i figured as much...I'm currently building a scale model to test that.<br> <br> My plan is to put a pole on either side of the door hole with a diagonal strap to...this will make more sense with a diagram...there.&nbsp; The red would be a pole and the blue would be a string/rope holding in that corner.<br> <br> Anyway we will see how the model holds up and move on from there :)
That looks really simple and functional - and you get that awesome big door out of it!
from my scale model test I think the door itself will actually be the most unstable part...however the larges size of coroplast I seem to be able to find anywhere is 4x8 feet which would be hard to fit the size and number of triangles I would need onto, so I still have quite a bit of planning to do.
My efforts here are humbled by Rob Bell, who builds the finest &quot;domes&quot; I've ever seen. The defining feature of his math is that all edges are of equal length - only the corner angles vary. Worth a look, with more info readily findable online.<br> <br> Short video that explains it well: <a href="http://www.thetalentree.com/zonotopia-by-installation-artists-at-the-burning-man-festival/" rel="nofollow">http://www.thetalentree.com/zonotopia-by-installation-artists-at-the-burning-man-festival/ </a><br> <br> Nice pic by the builder: <a href="http://www.vectric.com/forum/viewtopic.php?f=5&t=12257" rel="nofollow">http://www.vectric.com/forum/viewtopic.php?f=5&amp;t=12257 </a><br> <br> I'm a maker, he's an artist. This is what inspires me to start designing digitally and outputting to a CNC.
Great instructable! I've built a couple of these, but never out of coroplast. Great material for something more permanent. My initial thought was that this could be a fantastic hunting base camp-type structure. It would be much nicer than a tent. I wonder if a suspended tarp over it would provide rain protection.
I think so - corner poles with taught tarp between them, or even trees if you got em. Even when I tent-camp I like a tarp suspended above the tent for shade or rain protection. I also think a rain-fly nailed down at the corners could boost strength against big winds. <br><br>If you cut the dome shapes with tabs folding upwards, you would get a smooth interior with ribs outside. It would keep the tarp off the dome for better air circulation between them; might be hard to clip it together from the outside though...<br><br>I do like the dome for it's lack of flapping in the wind; ideally I can get it waterproof sans tarp.<br><br>Keep the ideas coming people...
epic idea! how waterproof is it, do you get good run-off? being from the UK, rain is quite a big issue.<br><br>Also you should make a video of you putting it up, or a stop motion?<br><br>good luck with the contest.<br>
Thanks! Unfortunately the instructable lacks a couple of the steps like cutting out the triangles and a stop-mo film like you mention. Waterproofing would be great, and I think V.2 will be tighter in the seams where tabs meet, so we'll see. It's the classic drawback for domes. This version is best for the desert.
Chronolapse is a free time-lapse program for capturing &amp; creating video, it works off your webcam or captures screen shots from your computer. It's really easy once you get the hang of creating the 2 folders needed for each video.
You could also (providing you have a large enough memory card) video the construction, transfer it to your computer then speed it up in windows movie maker. (if you use a PC - i'm sure mac and linux will have a similar solution.)<br><br>Just right click on the footage in the timeline, click 'effects' then select 'speed up double'. Click 'add' to add this effect to the footage - you can do this more than once - then click ok.<br><br>After that you just need to export it.
I think I'll do that next time I raise it; a time-lapse would really show off the method I found for easiest raising. The dome can be quite a handful during erection as moving one support pole can cause all the others to fall at once and give you some exciting moments. I took a while to come with an orderly process to get the thing up easily with one or two people.
Nice work, yourpalsparky. 2 thoughts: <br><br>1. If you attached the pieces not with clips, but with something more durable, maybe that would solve your slippage. I am thinking holes through adjacent tabs, with zip-ties through the holes. However, when you took it down you would have to cut and dispose of dozens of plastic zip-ties. <br><br>2. How much does the whole thing weigh when disassembled?
There is a bolt that has two small balls at the end and you can press them in by the top button. that would make it much more durable when camping lol.

About This Instructable


825 favorites


Bio: Bob
More by yourpalsparky: Folding Geodesic Dome
Add instructable to: