Conduit (metal pipe) framed domeSTEP 1: Deciding on a frequencyThe first thing you need to do is figure out what type of dome you want to build. If this is your first dome, the 2 or 3 frequency domes are recommended. These domes require a fewer number of struts, and therefore less confusion.

STEP 2: What Size?Once you have decided what kind of dome you are going to build, you need to decide on a size. Sometimes it is better to work out how long your longest or shortest strut will be and work from there. You can use the Reverse Dome Calculator when this is the case.

STEP 3: Calculating Strut LengthsThis is where the Dome Calculator comes in. Go to the calculator and plug in the radius that you decided on for your dome. If it's been a long time since your last math class, radius is the distance from the center to the edge of a circle or sphere. In this case, the radius is the ceiling height for the even frequency domes. For the odd frequency domes, the ceiling will be higher than the radius that you put in (unless you are building the 3/8 dome, in that case the ceiling will be lower).1v dome builders: Cut all your pipe the same length and skip to Step 5.

Step 4: Eliminating WasteThis part is tedious, but worth the effort because it will save you money and you won't have to feel bad about throwing away tons of wasted pipe. You will have to repeat steps 2, 3, and 4 to do this right. It may take a while, but I would think you were a bad person if you didn't at least try. Conduit is usually sold in 10' lengths, so your job is to figure out how to cut those pieces eliminating as much waste as possible. Make sure to add 1½" for each strut to allow for drilling. For all you 2v dome builders, it's easy because there are only two lengths involved. The magic numbers for a 2v dome cut from 10' conduit pieces are A = 5.3', and B = 4.7'. These numbers allow for holed drilled ¾" away from the ends. 2v people may now skip to step 5. The rest of you: Still with me? Play with the numbers until you can get the maximum number of struts using the minimum number of conduit pieces. You may try 2 A's and 1 C, or 1 A, 1 C, and 1 F. Don't forget that different numbers of struts are required. Don't get stuck with more or less than what you need. I never said this was the easy part...

Step 5: Cutting the strutsCut the tubes according to the strut factors plus 1½". This allows for drilling the holes ¾" from the ends. Cut the struts using either a hacksaw or a pipe cutter. If you use a hacksaw, 16 or 18 tooth blades work best. When making many cuts, it's always best to use a jig so all the struts are exactly the same length.

STEP 6: Flattening the endsOK, there are a few ways to do this part. You can either pound the ends flat with a hammer, which could be really time consuming, or nearly impossible if you are as small as I am. You can also use a vise, but make sure it's a fairly large one so it doesn't break after a few squishes. The way I like to do it is to use a press. The press in the picture is a 1 ton arbor press bought at Harbor Freight Tools. It was really cheap, but only lasted about 20 squishes. The 3 ton press worked a lot better, but it started to bend after about 150 squishes. If you can afford it, a hydraulic press seems like the way to go. If you flatten the ends with a curved die like the one shown below, the ends will be stronger and therefore less likely to bend under load. (click image to enlarge) Please notice the weld along the side of the conduit. If you flatten the end with the weld on the side, the conduit will be likely to split there. It can also split if the weld is in the center of the flat part. I personally haven't had this happen, but I spend good money on dome parts, and would rather not learn the hard way. Keep in mind that the flattened ends need to be in the same plane. If you take a few minutes to construct a simple jig for this, I promise you won't regret it.

Step 7: Drilling HolesTo drill the first hole in each strut, cut a V groove in a 2 X 4 six inches longer than the longest strut. Clamp it to a drill press with C clamps. Use a stop block so that all of the holes are the correct distance from the end of the pipe (¾" from center of hole to edge of pipe). Use a 3/8" drill bit (you may need to buy several). Titanium costs more, but lasts the longest. This gives about ½" from the edge of the hole to the edge of the pipe. To drill the second hole, you will need to measure the exact hole-to-hole (aka strut) length, along the 2 X 4 and drill a 3/8" hole there. Screw in a 7/16 carriage bolt that has its head cut off with a hacksaw. It will be tight since the hole is smaller than the bolt, but trust me on this one. You can use a vise-grip or a pipe wrench to screw it in. File the cut-off stump to a slight taper so the holes in the pipe will easily slip over it. Clamp the 2 X 4 back to the drill press so that when the first hole is placed over the cut-off bolt, the other end can be placed under the drill in the correct position. Pull the drill down so it just touches the pipe, and double check your measurements. If they are correct, continue drilling with confidence. If not, you know what to do. Continue this process with all lengths moving the pin as necessary. It would also be a good idea to mark the table and the jig when you get it set so you can tell if it is moving.

Step 8: Bending the StrutsNow the struts need to be bent to the correct angles. You can do this by clamping the end into a vise and bending the tube to a stop block. If any of the flattened ends are split, bend the pipe toward the split side so the split will be on the inside of the dome. The accuracy of the bend is not as important as drilling the holes, so don't hurt yourself on this one. I repeat, the accuracy is not that crucial, don't spend all day deciding if you need to bend an extra degree or not! When the dome goes up for the first time, the struts will bend to the exact angles on their own.

The bending angles are as follows:1v dome: bend 32º on each end2v dome: bend A's 18º, and B's 16º on each end3v dome: bend A's 10º, B's and C's 12º on each end4v dome: bend all struts 7º-9º on each end5v dome: bend all struts 6º-7º on each end6v dome: bend all struts 5º-6º on each end

Step 9: PaintingThe ends of the struts all need to be painted, because otherwise they will rust. Since you are painting anyway, why not color-code! I'm a big fan of color-coding, and when you try to assemble the dome you'll find out why. To make it even easier on yourself while you're in the desert, make a model using the same colors as in your dome. When you get to Burning Man, you can set the model down, lay out all of the struts, and sit back and relax while other people put it together for you. Well, not really, but it will make it a lot easier to put the dome together if you have a model as a reference.

Step 10: Break Time!Take a break, cause that was hard work. If your camp is anything like ours, you can't take a break because you just finished the prep work for the dome 3 hours before it's time to leave for the desert...

Step 11: AssemblyAhhh, the moment you've all been waiting for. Bet you're a little nervous if it's your first time. Don't be. If you followed these instructions carefully, your dome should go up smoothly.Domes can either be built from the top down or bottom up, depending on the size of the dome, and your tallest ladder. Building from the top down eliminates the need for a ladder, but you better have a lot of people helping. As the dome goes up, you will need one person at every vertex holding it up. If any of your poles get bent during this process, you better hope you listened to me before and made extras. Bottom to top assembly is much safer on the dome, but it means you have to bring ladders and/or scaffolding tall enough to reach the top of the dome. I noticed several domes last year without tops. Build the dome in layers whether you are going from top to bottom or vise versa. Don't get ahead of yourself. If you build in layers, the dome will pretty much support itself as it goes up. It might be a good idea to designate one person as the parts person. All this person has to do is lay out the next layer of struts on the ground for the assembly crew. This prevents over anxious builders from getting ahead of the rest of the crew. Don't tighten the bolts until all of the struts are in place. The struts will shift into their proper alignments as the dome is built, and they can't do that if the bolts are tight. Remember the dome doesn't get its strength until the last strut is in place and all the bolts are tightened.

Here are the assembly diagrams for domes 2-6.

Order of diagrams:

2v dome3v dome4v dome5v dome6v dome

If you are building your dome from the bottom up, here is some useful information:You will need to lay out the appropriate number of struts in a circle to get started. The numbers are given below.

1v dome - 5 struts2v dome - 10 struts3v 3/8 dome - 15 struts3v 5/8 dome - 15 struts4v dome - 20 struts5v 3/8 dome - 25 struts5v 5/8 dome - 25 struts6v dome - 30 struts

Step 12: Staking DownPlease don't forget this part. If you cover your dome before you stake it down, you will not be a happy camper when it catches wind and smashes into the cars parked a couple of feet away. Rebar bent into candycane shapes work really well for stakes. Make sure they are at least 2 feet long. Pound them in about every other vertex along the bottom.

Step 13: Covering your domeThe whole purpose of this IS for shade right? If not, you can stop here. Parachutes make really nice dome coverings because all have to do is pull the parachute over the dome and tie it down. The only problem with parachutes is that they were made to catch wind... Need I say more? You've gotten this far, you can make a covering. Be creative on this one. You can use bed sheets, canvas, or anything else you can think of. Reinforce all points that will be connected to the dome or they will tear with the slightest gust of wind.

Woo Hoo! Now that your dome is finished, you can sit back and relax, or wander around knowing that you have a really cool shelter to return to. Be sure to come and see us at Camp Sunscreen for a relaxing sunscreen massage. If you know where you and your dome will be, please e-mail me with your address so I can come check out your masterpiece and also take pictures for the photo gallery.

Recharge DomePurposeThis dome is intended to be a large shade structure for lots of people to lounge in. With a 32-foot diameter circle floor (with full headroom everywhere), even with furniture strewn about it is pretty comfortable for more than 25 people.

This page avoids repeating information on this page. You should really read that page first.

Frame - StrutsAs with the smaller dome we use 3/4" EMT cut to lengths averaging about 5 feet. The goals with the struts are:

• Keep the average strut lengths at 5 feet. We will get two struts (plus sometimes some small amount of waste) from each 10-foot piece.

• For each end of each strut, we need to add the following length past the intended hole location to find the pipe cut location: 3/4" for the extra squashed metal, plus extra length to overcome the loss due to bending. However we find that for this frequency dome, the bend angles are 7 to 9 degrees, and two (for each end) times 3/4" times (1 - cos(8 degrees)) is an insignificant 1/68 inch, so we'll ignore that. Therefore for each strut we'll add 1.5" to the hole-to-hole length to get the pipe cut length.

• We want to end up maximizing the number of 10-foot pieces which are only cut one time, i.e. not cut a second time to remove a waste piece. This minimizes both the number of cuts and the waste, and therefore maximizes the size of the dome.

To solve this puzzle first go to the frequency-four table on this page to get the strut quantities and hole-to-hole-length ratios. It's a really good idea to make spares, maybe 4 spares each of the C's and D's (there are more of them), and 2 spares of each of the others. However, because the entrance modification i'm planning to do replaces 2 C's, 2 D's, and 2 E's, i'm going to only make 2 spares of the C's and D's. (I don't want to eliminate all the spares of E's in case the entrance modification is not used some point in the future.) So now i am going to just have 2 spares of each length.

Whew, still with me? Here's the fun part. Next we notice that if the B's and C's are around 5 feet long, their strut ratios are so close to each other that the length difference is nearly a measly 1/8 inch. If you take advantage of this lucky fact, you can just plan to let that extra 3/4" outside the hole on each end of the strut be 3/4" plus 1/16" on each end - this will work fine, in fact the variations in that end bit will be more than 1/16" anyway. This means you will cut the B's and C's the same length, and only differentiate between them later. Now from playing with different permutatations of sums of pairs of strut ratios, you can get the following cutting plan which i believe is optimal:

Struts to cut from each 10-foot conduit Quantity of 10-foot conduits Comment

C + D 62 cut C's as if they were B's

B + D 10 actually the same as previous cut

B + B + waste 11

A + E + waste 32

F + F + waste 16

Things to notice:

• There are 131 total 10-foot lengths needed • 72 pieces are cut once and have no waste. 59 pieces require 2 cuts and have some waste. • To do the first 3 lines of this table, just cut 83 pieces off at the B length. Then pull 11 pieces back

out of the D pile and cut those at the B length.

And one final important detail: what are the lengths? And hey, what the heck is the size of this dome, anyway? Since B + D = a whole 10-foot piece, you use the strut ratios for those two pieces to solve: X * (0.29524 + 0.31287) + 0.125 + 0.125 = 10. (The 0.125 values are the total excess --- 2 times 3/4" --- for each strut.) This gives you X = 16.0333 feet as the dome radius, which you can then multiply by each strut ratio (or enter into the Dome Calculator) to get the hole-to-hole lengths. Then remember to add the excess back in to get the pipe-cut lengths.

Strutletter

Color code on assembly diagram

Quantity(including 2 spares)

Strut ratio(ratio of hole-to-hole-lengthto dome radius)

Hole-to-Holelength

Pipe cut length(hole-to-hole-length plus2 times 3/4" excess)

A yellow 32 0.25318 4.059' = 4' 0" 11/16 4.184' = 4' 2" 3/16

B red 32 0.29524 4.734' = 4' 8" 13/16 4.859' = 4' 10" 5/16

C blue 62 0.29453 4.722' = 4' 8" 11/16 4.847' = 4' 10" 3/16

D green 72 0.31287 5.016' = 5' 0" 3/16 5.141' = 5' 1" 11/16

E purple 32 0.32492 5.210' = 5' 2" 8/16 5.335' = 5' 4" 0/16

F orange 32 0.29859 4.787' = 4' 9" 7/16 4.912' = 4' 10" 15/16

Two useful doublechecks are that the pipe-cut lengths of B and D add to 10 feet, and that as promised B and C differ by only 1/8 inch.

One practical tip i figured out after many difficult cuts: open up the pipe cutter and put a drop of oil on each of the three pins that the three rotating thingies (2 rollers and a blade) rotate on. It really makes cutting about 5 times easier.

Frame - Entrance ModificationSee this page for the full details of how to do this. Here are the calculations for the strut lengths for this radius dome.

Dome radius is 16.033 feet. Declination (from top) of apex is 66 degrees, i.e. 16.033 times cos(66) = 6.521' = 6' 6" 4/16.

StrutStrut ratio(ratio of hole-to-hole-lengthto dome radius)

Hole-to-Holelength

Pipe cut length(hole-to-hole-length plus2 times 3/4" excess)

Top C 0.1914 3.069' = 3' 0" 13/16 3.194' = 3' 2" 5/16

Top D 0.2012 3.226' = 3' 2" 11/16 3.351' = 3' 4" 3/16

Middle C 0.3301 5.292' = 5' 3" 8/16 5.417' = 5' 5" 0/16

Middle E 0.3458 5.544' = 5' 6" 8/16 5.669' = 5' 8" 0/16

Bottom D 0.4381 7.024' = 7' 0" 5/16 7.149' = 7' 1" 13/16

Bottom E 0.4463 7.156' = 7' 1" 14/16 7.281' = 7' 3" 6/16

Note the middle and bottom pieces are made from stronger conduit as described on the other page.

Frame - AssemblySee this assembly diagram. The entrance modification will be for one of the large bottow hexagons. (Notice that there are only two types of bottom hexagons: larger ones and smaller ones that are even more asymmetric. Half of the bottom hexagons are twins of others mirrored in the opposite direction.)

Frame - Assembly Bottom-Up (Attempt)On August 11, 2001 some of us gathered in Precita Park in SF to see how far we could get assembling the dome. At some points there were as many as 7 people working on it, but the average work was probably more like 4 people for 3 hours. The bottom 76% of the pieces were put together, though it's worth noting that when building from the bottom up it gets much harder to put the higher pieces on. Anyway, this gave some idea how much work would be involved to do the whole thing, plus we learned to avoid one major mistake: make sure you're looking at the right color on the assembly diagram (orange/yellow and blue/purple are confusable).

Here are some photos of the extent of the assembly. Click to enlarge.

This attempt convinced me that bottom-up was not the way to go. Read on...

Frame - Assembly Top-DownJust after the bottom-up attempt, my brother gave a book about Bucky Fuller, in which i found the following bit of wisdom (referring to construction of another dome-type structure): "Units were built from the top down by pulling the assembly up a temporary mast as parts were added at the bottom. The mast-hoist method kept most workers on the ground, speeding the work and reducing the risk of injuries. Bucky would use this top-down building tactic repeatedly in the future." Specifically, with this dome, this technique would allow never having to take a nut off of a bolt to add more struts, which had consumed much time and energy with the bottom-up attempt. Each vertex could be assembled once, and only revisited to do a final tightening on the nut.

This made perfect sense to me, but how would i make a temporary mast for this dome? After hours of online research, i found a solution. There is a materials lift, the Genie SLC-18, which is perfect for the task, and readily available for rental at many equipment rental shops. (An older model, the SL-18, is essentially the same.) It lifts up to 650 pounds to a height of 18 feet. (I weighed the dome struts and calculated that with hardware the weight should be under 600 pounds.)

To get started, you set up the lift in the center of where the dome should be. You construct the top pentagon, with all the extra struts hanging down from it (in other words, a total of 25 struts) around the mast of the lift, so that the mast is going up through one of the triangles of that top pentagon. Then, with one continuous piece of rope (rated to well over one-tenth of the total dome weight; i used 400-pound "truck" rope) you rig the five outer vertices of the top pentagon to the lift, hanging under the fork. The top vertex should be centered very well on the lift in the left-right direction, and as close as possible to the mast in the in-out direction while leaving a little room for the dome to sway (say, 3 inches clearance). The top vertex should be as high as possible, since it will eventually be 16 feet high but the

fork only goes up to 18 feet high (well, not even quite that high) --- and keep in mind that your rope will stretch more after more load is placed on it. Using one continuous piece of rope allows you to easily adjust the assembled struts to be as close to level as possible, and also allows the load to be perfectly distributed between the five vertices, which is highly desirable. Do take the time to make sure the height, centering, and leveling are as good as you can get them before going on since its difficult or impossible to fix this later. The photos below (taken after more than just the initial 25 struts were assembled) show how the rigging should look. It's worth mentioning that Genie makes a boom attachment which would be better than the standard fork attachment, but it seems most rental places don't have it. If you use the fork just make sure your rigging is tied to the back part of the fork --- not the sides, from which it could slip off.

Next you start building one layer at a time. For each layer, you should first lay out all the struts needed to complete a new vertex at each new vertex location. Then, alternating working on each side in order to keep the dome as balanced as possible, hold together all the struts at a new vertex in about the right place, and add the nut and bolt to hold it all together. At this point the nut should be secure, but loose enough so that the down-hanging struts can rotate a little bit into place for the next layer. After all the new vertices are put together, the nuts of the vertices just above that (the previous layer you did) should now be tightened fully since all struts at that vertex are now held in exactly the right positions. Then, you use the lift to raise the dome up enough to do the next layer. This photo shows the dome partially assembled. The bottom vertices' nuts are loose, but all the nuts higher than that are fully tightened.

One pitfall we ran into the first time we did this was that one of the verteces above the layer being worked on went concave (popped in) while the dome was partially assembled. To fix that, one person lashed a rope around the troublesome vertex, and pulled it out (while everyone else tugged the dome in the other direction) and held it out while the layer below was assembled. After that layer was assembled, the structure was stable at the previously-concave vertex.

Another slight problem was that the rigging was tied slightly too low --- maybe 4 inches too low for the maximum lift height. When we got to the bottom layer, one person had to lift up a little on one spot on the dome while others placed the very bottom struts in their vertices. This was not too bad, but it would have been better to have tied it up to the right height in the first place.

After the last nut is tightened (hooray), get out your 16-foot stepladder (uh, you have one, right?), untie the rigging rope, and carefully detach the fork so that you can shimmy it through a top triangle and bring it down the ladder. (See photo below.) Then lower the lift and take it out through the entrance. All done.

It's worth it to use the lift at disassembly time too. You do the assembly procedure backwards --- crank up the lift mast all the way, shimmy the fork through a top triangle and attach it to the mast, tie up the rigging rope as before, and then start unbolting verteces one layer at a time, lowering the lift after each layer. You can take off each layer very quickly (we even had two wrenches going). Compare this to disassembling bottom down, for which you would have to keep moving the ladder (or scaffolding) around, and struts would be dropping from high up.

CoveringI must confess that when it came time to put the covering on all i did was watch, but here's the basic description. A 50-foot cargo parachute was used. First it was pulled over the frame using rope, the tall ladder, and long poles to occasionally poke the chute in spots where it got stuck on the outside of vertices. (The smooth carriage bolts kept snags to a minimum.) After it was centered on the frame (with a convenient vent hole top center), excess was folded over on itself on one side because the chute was slightly too large.

It was attached to the frame at one out of every (maybe) 8 vertices, where the attached vertices were evenly spaced over the surface. The attachment method required a large washer (or other round object) and two zip-ties (AKA cable ties) --- a handful of fabric was bunched up near the vertex, a washer was tossed into the bunch from the exterior, a zip-tie was used to trap the washer inside, then the washer (now trapped inside the fabric) was zip-tied to the frame's vertex. This is not a great picture but might give you some idea.

At the bottom, the chute was rolled up inside to leave the bottom row of traingles uncovered. This is critical for ventilation in the desert heat. Before it was rolled up the temperature started rising fast inside.

AnchoringFloor and AmenitiesWith carpeting on the floor and several couches inside, all i can say is that this was the best place to be in the middle of the day in the sizzling desert heat. At night, with a floor lamp lighting the interior, it was cozy. The only thing that would have made it better would be a water-mister (or air-conditioning!) to ke

As described here, stright rebar and rope was used.

CostsHere are some notes about costs for the materials. Fortunately i had already bought the shop press and the drill press. And we already had the chute from previous year's structures.

Item and quantity Cost (incl. tax and/or shipping)

3/4 inch EMT conduit 10-foot lengths, quantity 132 $322.18

1 inch EMT conduit 10-foot lengths, quantity 2 $8.10

1-1/4 inch EMT conduit 10-foot lengths, quantity 2 $10.74

Pipe cutter $9.69

Screw anchors, quantity 10 $42.12

Hardware (bolts, washers, nuts) ???

Titanium drill bit $15

Spray paint for color-coding pieces $22.83

Strapping tape for bundling pieces $9.05

Grand total $439.71 + ???

The Bamboo DomeThis is page 95 of "Domebook Two", a book that was published in the 70's and is very hard to find. It was written by Pacific Domes (not the same as Pacific Domes), and I was able to find it at the local library.

Bamboo grows fast, is free material for a dome framework. It might be possible to suspend a tent skin or mosquito netting inside, or pull a stretch cloth over the outside and shoot foam. Tools: a pocket knife and string. The following instructions were prepared by R. Buckminster Fuller. I haven't tried this yet.

Dome Assembly

The geodesic dome, as shown in the assembly diagrams, contains two different joints: a B joint which occurs at the vertices of all pentagons formed, and an R joint which occurs at all other points. The spans from joint to joint are BB, BR, or RR. The arc factors of these lengths are: BB=.26030616, BR=.31030984, RR=.32636688. For these factors, the radius of the dome is 1.00. To construct a 22' dome (11' radius) the lengths of the arcs would be as follows: BB=2.86', BR=3.41', RR=3.59'.

Cutting and Measuring the Members

There are only two different lengths of members used in the erection.

For a 5/8 dome, 80 B members and 90 R members are required.

A line of color can be drawn around the bamboo members at each measuring point. Use blue for the B points and use red for the R points.

Cross Assembly

The B cross consists of two B members whose lengths are: 1/2 BB plus 1/2 BR plus 12" extra at each end.

The R cross consists of two R members whose lengths are: 1/2 BR plus 1/2 RR plus 12" extra at each end.

With 12" extra on the end of each stick, there'll be a 24" overlap when the crosses are assembled.

Cross Tying

Place members at right angles to each other and tie firmly, but not too tight. During assembly of the dome, the crosses will twist into proper position as shown.

In all cases, when looking at a cross with the acute angles at the sides and the obtuse angles at the top and bottom, the member going from the upper right hand corner to the lower left hand corner always passes over the other member.

Stage 1 Assembly

The first stage in the assembly of the dome is the construction of the pentagons at the top of the dome. This process employs 5 B crosses.

Step A: Tie together two B crosses as shown in in the diagram. Note that the end measuring points have the same designation as the cross to which they are connected.

Step B: Add two more B crosses in the same manner as shown in step A.

Step C: Add fifth B cross between the untied legs. In order to insert this cross, all crosses will be twisted so that a regular pentagon is formed.

Stage 2 Assembly

The second stage consists of closing the five triangles around the pentagon. Use five R crosses.

Again, the end measuring points always have the same designation as the cross to which they are connected.At this point, the structure will tend to bow. Turn the figure so that it is concave downward.

Prop It

Lift the assembled figure off the ground to facilitate the addition of new crosses. Use five bi-ped props. Each prop consists of two bamboo sticks about 7 feet long, tied together near the top with a cord about a foot long. These props will then support the dome at equidistant points from it's apex; first at the five vertices at the top of the pentagon, later at five corresponding points on the top five hexagons.

Stage 3

For the third stage, use ten R crosses as shown.

Stage 4

The fourth stage uses 5 B crosses which close the five hexagons.

Stage 5

The fifth stage uses ten B crosses to close ten triangles. Six of the crosses can be seen in the diagram above.

Stage 6

The sixth stage uses ten B crosses and ten R crosses to complete the first horizontal band. We now have a 3/8 dome.

Stage 7,8

To complete the 5/8 dome requires two stages. The seventh stage uses ten R crosses and the eighth stage uses ten R crosses and ten B crosses. On the last twenty crosses, all members pointing towards the ground should be cut off 12" from the cross' central point.

The formulas behind the Dome Calculator

First of all, you need this simple formula:

dome radius = strut length/strut factor

which is the same as:

strut length = dome radius * strut factor

Now all you need are the strut factors! Strut Strut factor Dome Sphere

A 1.05146 25 30

5-way connectors 6 12

4-way connectors 5 0

Strut Strut factor Dome Sphere

A .61803 35 60

B .54653 30 60

4-way connectors 10 0

5-way connectors 6 12

6-way connectors 10 20

Strut Strut factor 3/8 5/8 Sphere

A .34862 30 30 60

B .40355 40 55 90

C .41241 50 80 120

4-way connectors 15 15 0

5-way connectors 6 6 12

6-way connectors 25 40 80

Strut Strut factor Dome Sphere

A .25318 30 60

B .29524 30 60

C .29453 60 120

D .31287 70 120

E .32492 30 60

F .29859 30 60

4-way connectors 20 0

5-way connectors 6 12

6-way connectors 65 150

Strut Strut Factor Dome Sphere

A .19814743 30 60

B .23179025 30 60

C .22568578 60 120

D .24724291 60 120

E .25516701 70 120

F .24508578 90 120

G .26159810 40 60

H .23159760 30 60

I .24534642 20 30

4-way connectors ?? 0

5-way connectors 6 12

6-way connectors ?? ??

Strut Strut Factor Dome Sphere

A .1625672 30 60

B .1904769 30 60

C .1819083 60 120

D .2028197 90 180

E .1873834 30 60

F .1980126 60 120

G .2059077 130 240

H .2153537 65 120

I .2166282 60 120

4-way connectors ?? 0

5-way connectors 6 12

6-way connectors ?? ??