Dome Tent Formula

Hey everyone,
after a long time fiddling with it I'm kinda proud to present my spreadsheet which calculates the fabric pattern of dome tents. It is based on the poles being parabolas which works pretty well for tents in the "usual" sizes.

The spreadsheet is in .ods format and can be opened with open office.

Download here:
ZELTFORMEL

Quick- Manual:
You enter your basic tent measurements in the upper left hand corner.
You will then get two sets of coordinates(X1/Y1 and X2/Y2). These represent the fabric patterns along the width and the length of the tent. The zero/zero is at the apex of the tent.
Hope someone has any use for it,

Christian Wagner

I'd be intersted in veiwing this speadsheet but I don't have Open Office.

What is it? Where can I get it (freeware)? Do I have any other options?

Thanks

Yep, Open Office is a free office suite that you can download from the openoffice.org site.

Sweet!!!
Just what we needed, someone who likes to sew and knows computer programing.
I actually do have a question... With out looking at the program yet, can it tell you the inner tent and outer tent? For instance, the inner tent hangs 2? inches below the poles.
Thanks for posting it. While I do not have a use for it, I could come up with a use for it.
Scott

Ooh! Smashing!

<Kate envisions teaching son's scout group to make tents... >

You would let the computer calculate two different tents. The first, the outer tent is bigger, the other tent would simply be two inches smaller.
Before this spreadsheet I drew a very accurate picture of the tent and took my measurements from there. The problem was that it would take forever and if you dicided half way that you wanted your tent two inches higher, you would have to start allover again. Now every dome tent you could imagine is just a couple of keypresses away.

One of my earlier tents (done by "hand")could be viewed here:

tent
The method was basically the same, just not computerized.

I could use some help getting started.

I downloaded open office.

When I click on your link I get a page showing a lot of info (not a spreadsheet). It shows, for example, folders labeled configurations, Meta-inf, Pictures, etc.

Where do I go from there?

Wow, I just realized that Windows somehow thinks that this is an archive- weird.

Hm, on my Linux system everything is ok.
The windows computer I'm working on right now doesn't open .ods files (Why the h*** couldn't MS office support totaly open, well documented document formats?).

You might get lucky if you rename the file to "*.ods" and then open it with open office (or MS excell with plugin if something like this exists....)

Thanks for trying. I'm already 3 skips above my computer skills and I was unable to do (or really understand) your suggestion here.

Oh well.

I made an Excel spreadsheet as well. Since I don't have Microsoft office I generated it with open office.

I cannot test it with Excel. Please tell me if it works and if you can get some use out of it.

If it won't work in Excel I'll find a computer with Microsoft Office on where I can convert the file properly.

Here is the link:
Zeltformel Excel

Christian-
I haven't had a chance to play with it, but the program opened in excel no problem. I'll see if I can mess around with it at lunch today.

Thanks for sharing such a valuable tool! This ought to come in quite handy!

Opened easily and worked.

How wonderful!

Thanks!

Opened and seemed to work well. Thanks!

Christian-
Thanks again for sharing this program with us! I finally took the time to play with it, and it seems pretty easy and straightforward.

One thing I was thinking about is how to use this with a trapezoidal instead of rectangular floor plan. Quickly trying to wrap my head around it, my thought was:

For X1/Y1 measurements (end panels of tent)
Head End (Wider): enter all dimensions and desired width of head end- use X/Y coordinates provided

Foot end (narrower): change width to match foot end width, all other specs stay the same- use new set of X/Y coordinates provided


For X2/Y2 measurements (long side panels of tent)
Length: Since you no longer have a rectangle, using the current input specs wouldn't work (the actual length of the tent side is longer). But all you need to do is determine the current length of the side (simple pythagorean theorum stuff):

(length of tent from step one)2 + (1/2*(head width-foot width))2 = (current length of side)2

(sorry, can't get it to superscript, so the "2" in each part is "squared")

A little calculator work and you are done. Does this sound about right to you?

I think you might get by with your method. There is definitely a difference in length between the broad and the thinner side at the "corners", so the "big" panel sits a bit askiew in-between.
A few irregularities here and there are usually no problem and are compensated by fabric stretch.
But please keep in mind that this is definitely just an aproximation. While the spreadsheet- used for the intended purpose, a square tent- is accurate to the letter, using it for a tapered tent isn't. Please use a paper model and even a "cheap fabric prototype" before you sacrifice your expensive fabric.

BTW:
Not only square tents could be calculated with the spreadsheet, also polygonal dome tents (regular polygon)are possible.
The tent width is the length of one polygon segment, the tent lenght is two times the apothem of the polygon.
Then use the values of X1 and Y1 to cut out your fabric.