Ulam Spiral Quilt

I've actually made some good progress on the writing I'm supposed to be spending 100% of my time on, so I am rewarding myself with another insane quilt: An Ulam Spiral. (You can read all about Ulam spirals at that wikipedia page.) This quilt was suggested by Dan Brumleve in a comment left on my Infinity Pi quilt blog post. (Actually he wanted an Infinity Ulam quilt, but I can't think of any way to do that, so I'm just making a finite version.)

Nina suggested representing each prime number by an in-and-out spiral, which looks cool, and should lay down enough thread to make the primes stand out. This pattern should stitch quite fast, because it's got a lot of straight lines in it.

I made two designs, low density (primes up to 1225) and high density (primes up to 9801). I am, of course, doing the high-density one first.

Here is the low density version, where you can see the individual spirals.

And here is the high density version I'm actually going to stitch. The lines will be about an inch apart.

I'll start it later this afternoon (Saturday May 7th, 2016 for you people reading this years from now). If you want to be notified when stitching actually starts, sign up for the StitchCam email list at the StitchCam page.

I'll post again when it's done and I have pictures of it.

Finished Infinity Pi Quilt!

Yesterday I started making an infinity-pi quilt, thinking it would take several days to finish. Thanks to my stupidly looking at the stitchcam at 2AM and thus being forced to go into the office to stop it from running forever without bobbin thread, it actually got done early this morning. Total stitching time was around 12-15 hours.

I am extremely pleased with the result, and have decided to make the quilt available for sale. Due to the stitching time, and the use of expensive wool batting, this quilt costs 200π ($628.30), twice the price of the older, lower-density pi quilt.

The older pi quilt is a very warm, puffy quilt. Nina says it's her favorite of all our designs. But it only displays about 150 digits of pi. This new one is much thinner (due to the dense stitching), but it displays all the digits. Yes, all infinity of them! Well, technically, after about the first 5800 digits they start getting hard to read, and after about 10,000 digits each digits is represented by less than one whole stitch (to the point where the last infinite number of digits is represented by a single stitch). But conceptually they are all there, because the pattern converges on an infinite number of infinitely small digits arranged into an infinite number of concentric rings of thread. (Actually there are only 28 rings, but what's a little factor of infinity between friends?)

The design is one single continuous line of approximately 420,000 two-millimeter stitches. You can watch the machine making this quilt in these time-lapse views from the stitchcam (one from the overhead view, one from the camera mounted on the stitching head).

Here is a real-time view of the first 20 minutes of stitching. (Total stitching time was closer to 12 hours.)

I tried several different functions to determine the rate at which the digits get smaller as they go around the circle. The obvious choice would have been to have it be as if they were on the surface of a sphere, but this ends up with too wide of transition zone between reasonable-size and too-small digits. What worked best in the end was simply a sine wave. It's as if you are looking over the "horizon" of the sine wave. At first the sine rises with a fairly constant slope (digits all the same size for quite a while, getting smaller only rather slowly). Then quite quickly the curve turns over and starts to get flat (so the digits get small very quickly, going from easily readable to one-stitch-high in just three revolutions around the circle). Within the resolution of the 2mm stitches, everything is smooth and continuous: The digits just get smaller and smaller until eventually they are nothing but abstract squiggles, and finally a smooth circle of infinitesimally small digits.

Needless to say, this pattern is 100% computer-generated. The only human contribution was to select the font, and write the code for kerning, spiraling, shrinking function, etc. Basically art-directing the algorithm to produce a pleasing end result. Pi digits courtesy of Mathematica.

We've only made one so far, with dark blue thread on unbleached cotton fabric. I think it would look good with gold on black, but Nina is voting for unbleached on unbleached (which looks really good in our lower-density pi quilt). If someone orders one, we'll also make a square design with the corners filled in with some kind of simple fill pattern.

An added bonus of the round design is that it folds into a slice of pi!

Infinity Pi Quilt

I'm trying a new, slightly insane quilt: A version of our best-selling Pi Quilt, except with an infinite number of digits. Well, technically, we won't actually stitch all the digits, because once they get smaller than a single stitch around the outside, you couldn't actually see them anyway. But you can imagine they are all there.

I'm hoping that somewhere in the vicinity of five or ten thousand digits will actually be visible. (The file technically contains about 15,000 digits, but I suspect they will start to break down well before the end.) How will I know how many are actually visible? Easy! I'll look for the smallest visible ones, and then determine the very last ten or so digits that I can actually make out. Then I'll do a search in the sequence of digits to find at what position those ten digits occur (which will almost certainly be unique in the first billion or more digits).

I actually have no idea if this quilt is possible: It might get so bogged down around the outside that I give up. Time will tell (i.e. after about 3 days I'll probably give up.)

The quilt is starting now: If you see this any time in the range of May 3rd to 5th, you can probably see it running on the stitchcam.

Exhibiting at the Boneyard Arts Festival

PaleGray Labs (which is the textile collaboration of Theodore Gray and Nina Paley) will be hosting an open studio and show of hand-made and robot-stitched quilts at the 2016 Boneyard Arts Festival in Urbana, Illinois on April 8-9. Come to our studio in downtown Urbana to see quilts and the machines that make them! 

Come see Behemoth the giant quilting robot!

See the Quilt Cave, set up for this show only! With better lighting than in this terrible photo!

Enter the Quilt Vault and see the treasures within!

Hand made quilts of stunning beauty, safe in the Quilt Vault.

On exhibit along with the room-sized Behemoth will be our embroidery machine, sailmaking machine, and several foot-powered antique sewing machines, along with dozens of quilts. All the machines will be in operation making quilts and embroidered things throughout the show.

Our studio is located in the former bank building now known as County Plaza, which is across Main Street to the north of the County Courthouse, just north of Lincoln Square mall. Officially the address is 102 E. Main Street, Urbana, but actually you want to go around to the North side of the building on Water Street, then walk down the ramp towards the parking structure and enter the north door of the building.

 

In case you saw one of our quilted flyers around town, yes, we made those in our studio.. Here is the long-suffering Gretchen learning the fine art of quilt binding by using them as practice:

Woah, Yarn!

William, the dealer from whom we got our giant quilting robot, sent us a video a few months ago of a new technique he'd invented: Stuffing thick yarn through the center hole of the hopping foot and letting the machine stitch it down to the quilt. 

This works amazingly well, though with some limitations (no breaks in the pattern, and no sharp corners).

I'm not sure what we'll use the technique for, if anything, but it's really fun that it works at all. I did four experiments. The first one, the Pi quilt pattern, was a failure. Almost tore the fabric. Then I made a test pattern with only smooth, gentle curves and no breaks. That worked great.

This style of yarn seemed to work best:

This kind tends to get bunched up and look sloppy sometimes:

And this kind just always look sloppy:

All the yarn I tried was super-think, because I feel that it has to be thick or the needle is likely to miss it. There is nothing holding the yarn in the proper position other than the fact that it's as big around as the hole in the foot, so it can't really get out of the way of the needle.

A real couching head would ensure correct placement of the yarn and thread, but it would also cost money, and doesn't currently exist for this machine. This technique, on the other hand, costs nothing (though I might decide to bend up a wire coat hanger to make a guide for the yarn).

Embroidered Animation! Finally!

Nina and I have been working forever on a project to create a short animation where every frame is rendered in embroidery. It's finally finished and ready for the world! You can read Nina's Blog post about it, or watch it here.

Every frame in the video is simply a photograph of an object that exists in the real world (in fact, you can buy them). There is no Photoshop manipulation. All the close-up animation of the figures is photos of the 6-frame sheets as you see at the start of the film.

The song is something to do with passover. Sorry, not my thing, so I can't tell you much about what it all means (see Nina's blog). All I know is that it's a folk song, kind of like the spider-that-ate-the-fly song, and that it's sung in Hebrew and Aramaic (which sounds as ancient as it is).

There's a good bit of technology that went into creating the stitched animation. I've given several talks about it, but never posted about it online, because we were waiting until the film was done.

There are two reasons it's not easy to make this kind of animation (other than that it's not easy to get started on something so obviously more work than it's worth). First, embroidery machines only go so fast, and even a small bit of animation requires a lot of frames (this film has 516 individually stitched images running at 12 frames per second, with some looping and repetition). It just takes time to do that much stitching (about a month in this case).

The second problem is that the software available for creating embroidery designs is not up to the job. It's stuck, both conceptually and stylistically, somewhere in the late 1980's. In particular, it is utterly impervious to attempts at automation.

Automation is crucial in animation, both because of the scale of the problem, and because if you want consistency from frame to frame, you want to avoid manual steps that introduce variability. 

So we created all the embroidery designs using custom software we wrote specifically for animation embroidery, which allowed us to control the exact placement of stitches, not one frame at a time, but over all the frames as a whole.

The process starts with Nina's animation (which she does using Macromedia Flash, because that's her tool of choice, and because it can export animation sequences in vector file format, unlike crap Flash after Adobe ruined it). Here's what a frame looks like at the start:

Here's what it looks like when imported into Mathematica (my tool of choice). This is Mathematica's beautiful rendering of its Region[] objects, which allows you to see that we've preserved the full polygons for each moving part of the figure.

To see this better, we can move one of them to the side:

Mathematica's region functionality is quite powerful. RegionIntersection[] gives us clipped polygons that include only what's visible:

We start with the unclipped polygons because they are used to determine the direction of stitches (always perpendicular to the major axis of the polygon). Because, in Nina's style of animation, the polygons don't change shape, this means the stitch direction will follow the movement of the figure, making the final animation look like a single stitched figure is moving, rather than a hodgepodge of separate figures.

This is the result of filling each clipped polygon with stitches based on the orientation of its unclipped form:

You can see all the zig-zig stitches (called satin stitching), but notice that there are also some lines haphazardly crossing the middles of patchs? Those are traveling lines that let the machine get from one patch of color to another of the same color, without having to stop and cut the thread. This is crucial to maintaining fast, efficient stitching. You don't see them in the final result because they are always underneath later satin stitching. This turns into an optimization problem: Figure out which colors to do in what order, to minimize total thread cutting. For example, these were the first two steps in making the above figure: Notice how the traveling lines will all get covered later. Our code optimizes this automatically.

Here is the stitched result. Notice how stitch direction makes the different parts of the leg clearly stand out from the body, and from each other, even though they are exactly the same color. The interplay of light and thread is a delightful aspect of this style of animation!

Even just filling a patch is far from trivial. You can't just start at one end and stitch to the other, because you might stitch yourself into a corner. Imagine a painter who is painting the floor of a house with a complicated set of connecting, branching hallways. If you start painting down one dead-end hallway, you'll paint yourself into a corner and not be able to get out to finish the rest of them. Instead you have to walk to the end of each side-branch and paint backwards, until you reach a branching point, then walk down the next branch, etc. Filling with stitches is just like that, except you're only allowed to move the brush in one direction, which further complicates the issue. Here is a little animation I made testing the code we wrote for solving this problem (which turns out to be largely one of graph theory). The lines are "walking stitches" used to get to the ends of the "hallways" and the filled patches are the satin stitches that will cover them up.

Of course it matters what direction the stitches are going. This next clip shows how completely different the filling order is as you change the direction:

It took a while to get all this code right, but of course it's crucial that it cover every possible case, because when you're doing animation, it's not about getting one frame right, it's about having an automated process that always gets every frame right, not just once, but every time there is an iteration of the animation requiring a re-render of the frames. We must have generated tens of thousands of frames (just generated the files, not actually stitched them!) before it was all looking good.

You can see the finished animation at the top of this blog post, and below is a version that is just a run through of all 516 frames (with just a bit of looping, but no cut-aways), in case you want to concentrate on watching the stitches.

In keeping with Nina's free-everything copyright-is-evil philosophy, the embroidery files used to create every frame of this movie are available under Creative Commons license. You can download them (in PES format) from https://archive.org/details/ChadGadyaEmbroideryFiles_20150710

Such a Pretty Molecule!

After my last blog post about molecule quilts for sale, a rush of orders and enquiries came in. One person asked whether it would be possible to make a quilt of cyclosporine (a drug used to help prevent rejection of transplanted organs).

The first structure I found for the molecule looked like the picture on the right. Not a terrible molecule, but see the abnormally long bond line on the bottom left? That's a symptom of poor layout of the atoms, which obscures a very interesting fact about this substance: It's a big ring! It's a very unusual cyclic peptide (short protein) made by a fungus.

I looked around for a nicer version, and found this lovely rendering, which makes the cyclic nature of the molecule very obvious! Unfortunately it's not ideal as a starting point for a quilt, because all that empty space in the middle is wasted, meaning the individual atoms would be too small.

So I took this starting point and rotated the longest of the protein side chains by 180 degrees so they point inwards, resulting in the design you see at the top of the article.

This should make for a really lovely quilt, and I hope someone orders it so I can stitch it and then post photographs of the real thing! (It's been added as a stock item, so you can buy one right now if you're just overwhelmed with how cool this molecule is.)

By the way, if you're wondering why I can just bend things around willy nilly without making the structure wrong in some sense, it's because this sort of 2D structure diagram is never really a true representation of the actual shape of the molecule. The uglier structure is in a sense more accurate in that it shows more bond angles closer to what they really are, but both are full of compromises. In any case the real molecule is 3D, not 2D. Here is what it actually looks like (from Wikipedia). Notice how lots of things are on top of each other: The only way to flatten this mess into a clear 2D diagram is to bend and shift it around in quite arbitrary ways. The cyclic structure is the one that most clearly illustrates the logical layout and connectivity of the molecule, which is what these diagrams (and quilts) are meant to do.

Molecule Quilts Now for Sale!

After several months in stealth mode, I've decided that in honor of C&EN (Chemical and Engineering News) doing an article about them, I should really start selling molecule quilts.

The basic idea here is that I've written Mathematica code to automatically create a quilting pattern from any MOL file. (Actually I did that last year, but am only now getting around to commercializing the idea.) I've come up with some dumb and/or funny ideas for molecules you could put on a quilt, but really I can do any sensible molecule just as easily: The code is entirely automated.

I have a page that tells you everything you need to know about molecule quilts, and their very reasonable pricing.

New Custom Word Quilts For Sale Now! Have a clever Idea? Get a special deal!

For the last month or two we've been experimental with word-quilts like you see here. I've got reasonably robust Mathematica code to automatically construct a stitching pattern for any set of words, and Nina has found a pleasingly simple combination of font and background pattern to focus attention on the words.

So we're ready to see if anyone will buy one....Eventually our intention is to have certain stock designs available at fixed prices, and custom wording available for a higher price. But we need more ideas for clever things to quilt into words, and we've got a quilt show coming up where it would be fun to have some more word-quilts.

So for the next week (April 1-7) if you place an order below for either size of word quilt (Queen or Twin) you'll get a field where you can fill in any words you like for the same price as the stock items will be. The only caveat is that, if you think of something particularly clever,  you have to let us keep the quilt until Arpil 12th when the show is over so we can exhibit it. And if you have to agree to let us use your clever saying as a future stock quilt item. 

So, what will it be? Cheesy saying? Deeply meaningful sentiment? Happy Birthday Quilter-Bob? If you can write it, we can quilt it (including Chinese and Japanese characters, by the way).

When deciding on what the say, take a look at the examples and take into consideration that the more words you have, the smaller they become. Smaller words are less puffy, so generally the best word-quilts have a small number of words, with a few that can be made to stand out extra-large. (Also, if you happen to like any of these specific examples, don't feel compelled to be original. We'll sell you these designs too!)

After you send in your order, we'll get back to you with a proposed specific design (feel free to suggest line breaks and what to emphasize, or email me at theodore@theodoregray.com in advance if you want to discuss what would look best).

So far the only things I've thought of are silly phrases, but Nina contributed the lovely opening lines of On Children by Kahlil Gibran. Then again, she also contributed the one below. 

Here's what one looks like on a bed. With lots of small letters they can be quite thin, but with a small number of large letters, they are thick and puffy (we use 20-oz batting with approximately 1.25" loft).

Custom Word Quilt
from 299.00

We can make a quilt out of any set of words you like! We'll even do naughty words, if that's what you want. When you place your order you'll have a chance to specify which words specifically you want. Keep in mind that the fewer words there are, the better they will look: 10-30 words maximum is a good target. "Happy Birthday Bob"? The sky's the limit on quilted word cleverness. 

Reverse appliqué letters (which means different color fabric for the letters) is available for an extra charge. (If you know what reverse appliqué is and are willing to do your own cutting out of the letters, you can order at the regular price and ask add a comment that you'd like double fabric so you can cut our your letters: No extra charge for that.)

Include special requests for fabric color or layout in the form you will get on checkout and we'll get back to you if there's any trouble with your choices.

Size:
Quantity:
Add To Cart

Order here! The order system doesn't say anything about selecting the fabric or thread color, because we have opinions about what looks best, and what we can produce most efficiently. However.... If you also have opinions, and particularly if you are ordering a Queen size quilt (which does not need to be combined with a second one on a single piece of fabric), feel free to email me or include requests for custom colors in the order form. We can't promise anything, but will consult you on the options and happily return your money if we can't come to an agreement on what to make.

Same goes if you have opinions on the font to use. In principle our code can generating the letters in any font available in any computer-compatible format (i.e. anything I can get for a Macintosh), but some look much better than others, for reasons that are not always related to how good the fonts look in print. If you'd like to suggest a specific alternate font, please feel free, and if it seems plausible, we'll send you what the generated design looks like and you can decide whether to have it stitched up.

Pi Day Quilt

(Please note: These are actually for sale, just scroll to the bottom if you want to order one....)

Tomorrow, which is Saturday March 14th, 2015, is being widely touted as a super-special pi day, because it's 3/14/15 and pi is 3.1415.... (Of course this only works in the US where we use the month/day/year system. Countries that use the more logical day/month/year system have their pi day on 31/4/15. Unfortunately April only has 30 days, so I suppose they have to celebrate it on May 1st.)

But back to the subject of pi day: Needless to say, I made a quilt for it!

Actually I had been paying no attention to pi day until yesterday when I heard the first people talking about it, but it just so happened that I had worked out a design for this quilt on a flight home from London a couple weeks ago, for no particular reason. Luck favors the prepared, eh?

I stitched it up yesterday in just about an hour. Here's a 60-second time lapse of that process recorded on the stitchcam:

Here are a few more pictures of it:

And guess what! If you like it, you can buy it (or one exactly like it)! Yes, now that we have experience with volume production, we are all about actually selling quilts, stitched by our fabulous robotic quilting machine that just loves to churn these things out. Order below, don't delay, you know you want one!

Pi Quilt
from 133.13

A fabulously nerdy quilt for an irrationally low price: $133.13 (the fourth root of pi) for a 46" square version and $314.15 for the full Queen size (94" square)! This beautiful, warm, puffy quilt displays over a hundred digits of pi rendered entirely in stitches for a gorgeous sculptural look. 100% cotton top and back fabric with 100% polyester batting. There is a choice of fabric and thread colors, but we strongly recommend unbleached cotton with natural unbleached thread. This allows the texture to really stand out.

Size:
Quantity:
Add To Cart

Periodic Table Quilt Backlog Cleared!

Just before leaving for London two weeks ago I put up a link for ordering periodic table quilts. The result was an exciting backlog of 16 orders when I got home 10 days ago! It takes about four hours of stitching per quilt, so we can produce at most 2-3 per day and I really had my work cut out for me. There is a certain irony in complaining that you can only produce two quilts a day, given that people routinely spend months making a single one, but such is the power of automation that it allows you to complain about what would previously have been considered an impossibly high rate of production. (I understand that in China there are factories producing over a thousand quilts a day using the same type of machine we have, though obviously with more than one machine, and with far less stitching than ours!)

We've run the quilting machine quite a bit over the last year, but never in a real mass-production mode. That is, of course, what this type of machine is intended for, so I felt good about finally letting it loose to fulfill its destiny of filling the world with quilts. (Needless to say, it spent the first two days behaving very badly until I finally got all the bits adjusted right, after which it has been stitching perfectly.)

With a volume of orders in hand I was able to step up purchasing, including a whale of a lot of batting (incredible amount of volume for the money), and a 100-yard roll of 108" wide unbleached cotton fabric (you have no idea how dense cloth is until you've tried to lift a roll like this!). I made a rolling stand for it because it would be nearly impossible to unroll without something to hold it up:

Working 12-hour shifts (the machine, I mean, not me, I just changed bobbins every few hours), we finished and shipped out the last batch of quilts yesterday:

Left over is a mountain of trimmings! There's always about 4" of excess fabric and batting around the outside where the sandwich is held in the frame clamps. It gets recycled into pillow stuffing and fabric scraps for various purposes. But right now it's still blocking the view out of our inner office window.

It was fun being a textile manufacturer for a week. The challenges are different than being an author or designer, but no less interesting or worthy of attack. If we have continued success with this and other quilt designs, I can see many opportunities for streamlining the process, and no reason why we couldn't operate a profitable textiles business here in the midwest.

Periodic Table Quilts

UPDATE! These quilts are now for sale!

Click here to order one

I've made a bunch of periodic table quilts recently, incrementally improving the design on each one until I'm pretty happy with it. There are quite a few issues that come up trying to do this...

The first question is font. Bold, sans-serif fonts (Arial Black in this case) look great because they puff out nicely, as in this example:

But if you don't have those lines in the background to connect the letters, you end up with a lot of separate regions, which requires a lot of clipping of threads between letters. And the space between the letters puffs up just as much as the letters, making them harder to read because the negative space shapes are similar in nature to the letter shapes. That's an annoyance you can largely eliminate by using a serif font, especially one (like Bodoni 72 in the next example) that has extra-long serifs, allowing neighboring letters to nearly touch each other.. As an added attraction, it also has strong variation in stroke width, which means the interior parts of letters like e and a always come very close to the outside at some point, making it possible to connect parts and letters to each other without a noticeable connecting line of stitches. All the words in the titles here are stitched without breaks:

For this reason I chose Bodoni 72 for the element symbols and titles, except for variations with background lines.

Then there's the question of the font for the small lettering in the tiles (the element names and atomic numbers). My first inclination was to use a bold font, thinking that would be bold and readable. This turns out not to be the case, because you get only the outline of the letters, not the whole area filled in. With a very bold font, the space between letters is about the same as the space within the letters, and the letters blend together too much, as in this example:

It turns out to work much better to use a thin font (Nobel-Light in the following example) to get maximum separation between letters and the space between them.

There's another subtlety with small lettering: stitch placement error. The machine very annoyingly re-sample all stitch paths to a fixed stitch length (a long-standing bone of contention not easily remedied), which means that when the line turns a sharp corner, that corner is liable to being rounded over. Look at this horrible rendering of protactinium:

See how the P and the R don't close up? That's because the inner circles are stitched in such a way that the line changes direction when the connection is made. Compare to this improved version:

It's still far from perfect, but at least there are no gaps where lines are supposed to be complete. That's because both inner rings are now stitched in such a way that the stitching line crosses over at the connection points rather than doubling back. (This is done with code that, having decided to link two parts of the design with a connecting line, looks at the curvature of the incoming and outgoing lines, and if necessary flips the order of stitching of one of the parts of the design to ensure that the line always exits the connection on the opposite side from the one it entered on. As long as all parts of the design are loops, and they are each connected at one point only, it's a theorem that you can always make all connecting points into crossing points.)

I should mention at this point that each square in the design is a single connected line, no skips. That's done with some new code I wrote that takes any set of loops and splices them together at their points of closest approach. It happens to be a fact that the outline of any stroked shape (e.g. a letter) will always consist of one or more complete loops, and they can always be spliced into each other. (Then there is one more loop that is the square around the outside.) Notice how cerium, for example, connects the letters of the name at the bottom, while protactinium connects to the bottom only in one place, with the letters then connected to each other. That's because protactinium is such a long name that the code has to compress it horizontally to make it fit, resulting in letters that are closer to each other than they are to the bottom. (This process is 100% automated, no human was involved in the layout or routing of any element tile, other than to set the rules of the game.)

I've just started making a black-background one, and it's looking nice!

Here it is stretched and mounted on a frame:

A brief note on technology. The design was, of course, done with Mathematica. (Lord knows how else you could do it, I certainly wouldn't want to try!) The letter forms were acquired using a trick that lets you export text in any font to EPS with all the letters converted into polygons, then re-import the EPS and extract from it those polygons. (This is one line of Mathematica code.) Further code measures the resulting outlines and fits them into the space available for each component of each element tile. The meat of the code is the part that recursively links up parts of each tile at their points of closest approach, resulting in one line for each element. The periodic table as a whole is then linked up with attention paid to the order of stitching to minimize warping and placement errors in the final result.

Once I have a few of these finished in different colors and have set up a shop for people to buy them, I'll tell the people over on my other blog about them, but for now I think it's too much stitch-nerdery for that group! 

(UPDATE! THESE QUILTS ARE NOW FOR SALE!  CLICK HERE TO ORDER ONE)

Here are large images of the two final designs, in case you want to see what the stitching pattern looks like. First with a serif title font with no connecting lines: Looks best with a highly contrasting thread color:

Then with sans-serif title font with connecting lines. Looks best with a low-contrast thread color:

Framed Fish

Yesterday we stitched a fish, and today we mounted it in a frame. Today's blog is about how we did the mounting. I don't know if anyone else mounts quilts this way, and I'm not sure I would recommend the technique, but it's what we've been doing.

The process starts with making a really, really thick, double-quilted thing (Nina calls it a cross between quilting and upholstery). These things generally do not lie flat, for reasons discussed in the previous blog post. But look how puffy it is! This one has two layers of 1/4" batting on the top quilt layer and two layers of 1" batting on the bottom layer.

There are two layers of appliqué with four or five wavy lines of stitching around the edge. Jury's out on how good this actually looks.

Notice the extra band of close parallel lines all the way around. That's the part that is going to wrap around the frame. The arches are catenary curves to distribute the stress of stretching, which isn't really a factor for this one because we're trying out what it's like to stretch only quite gently.

Here it is wrapped around and hooked onto the screws (which you don't see in the picture above because they were not in yet at the time):

And here is the final product again! So puffy!

Nina wants to do it again but as a "real quilt" this time, rather than a half-quilt, half-mattress monstrosity. Unfortunately during the making of this quilt a wooden shim fell off the machine and into one of the main drive belts. The shim is splinters now, and the belt will never be the same. We will have to wait for a replacement to arrive from China before we can use it again, sadly.

Quantitative Stretching

Welcome to my new Stitching Blog. It's like my regular blog except all about quilting and embroidery. I've separated the two, because I get the feeling that people interesting in my science writing and app-making activities may find all the stitching a bit tedious, and vise-versa. Also, I have taken the liberty of using the same list of subscribers to my stitchcam as the list to be notified (via rss feed) when there's a new post on this blog. I figure if you're interested enough in stitching to get real-time notifications of a quilting machine running, you're probably interested enough to hear about an occasional blog post.

So without further ado, my first new stitching-related blog post. I'm afraid it's a rather technical one....

One of the big problems with fabrics and quilting is that fabric is not a proper engineering material. It's stretchy and sloppy and never goes exactly where you want it to. The situation only gets worse when you add batting to the equation. 

We've been experimenting with extra-thick batting, as much as two inches thick, and have had a problem with the resulting "quilts" not lying flat, because some parts of the pattern shrink the dimensions of the fabric more than other parts, resulting in a sheet that is internally stressed. 

You might think it's a simple case of more stitches equals more shrinkage (as it more or less is with embroidery), but this is not the case. 

To see why, consider a cross section of a quilt with different spacings between the quilting lines. When there are no lines, the fabric on the top and bottom are flat, and the piece overall will be just as long as the fabric originally was. As you add more lines, the fabric is forced to go up and down, so even if the fabric isn't physically compressed, the piece overall will get shorter.

Here is a schematic illustrating this fairly obvious fact. Clearly if the lines (the top and bottom fabric) stay the same length, the overall length of the quilt must get shorter.

But what if you keep going? There is a fallacy in this drawing: The thickness of the quilt is staying the same. Clearly the following is NOT what happens if you add even more lines:

These diagrams get more and more absurd, because of course what actually happens is that the batting gets hammered down, the piece gets thinner overall, and the fabric goes back to being flatter. And that means the overall piece should start getting LONGER again, at a certain point. That's what I wanted to confirm and quantity, so I had Behemoth stitch twelve different test strips like these, each about a meter long:

Here is the diagram again, except this time the widths shown are real, measured widths from my experiment. (In the diagram below, the number of humps is real and the relative lengths are real, but the thicknesses are schematic, because I didn't measure the actual thicknesses):

As you can see, there is a minimum length around 30 humps, and by the time you get to 200 humps (0.5cm line spacing) the thing is well on its way back to its original length.

Here is a plot of the lengths as a function of line spacing (the right-most data point represents infinite line spacing, in other words the original fabric length):

The interesting fact about this is that, because there's a minimum, there are going to be two ways to get any given amount of shrinkage, a large-spacing way and a small-spacing way, one on either side of the valley. In order to get a quilt that lays flat, you don't have to keep all the spacings the same, you can have zones of stitching width spacings on either side of the minimum.

These tests were all with lines in only one direction, but what if you add crossed lines in the other direction? I did a second set of twelve test strips with lines going in both directions, like these:

The following graph is a bit harder to read. The horizontal axis represents the line spacing in the direction of shrinkage (just like in the graph above). The vertical scale is again overall length of the piece. The lines connecting data points represent sets of similar spacing in the lines going the other direction. The bottom set has no cross-lines (i.e. it's the same data points as the graph above, except a smaller number of them shown). As you go up, each line represents more and more closely spaced cross-lines. The data points are labeled with the line spacing in the shrinkage and crossed directions respectively.

The result is as expected: The more closely spaced the crossed lines are, the less shrinkage there is, regardless of how closely spaced the lines are in the shrinkage direction.

Now all we need to do is actually use this information to make something pretty that doesn't warp.... In the mean time, we've been experimenting with the other solution: Stretching on a frame.

This quilt is "double-quilted", using the term Nina invented for a thing I decided to try because why not. It's basically a quilt on top of a quilt, so we can have a secondary level of relief that isn't hammer down overall. I'll write a full blog post about this technique later, but here's a closeup that gives an idea of what it looks like:

Was all the quantitative measuring useful? Maybe.... So far I've used it only to create an interpolating function that I have used in some calculations involving how wide to make flaps that wrap around the wooden frame holding up stretched quilts like this. Hm, that's probably another blog post too.