Monthly Archives: January 2012

Spoonflower Custom Printed Fabric Review and Recommendation

As I mentioned last week, I placed an exploratory order with Spoonflower, an online service bureau that custom prints fabric (of all sorts, from cotton sheets to upholstery canvas to silk) with whatever you want. I created an immense image that’s a collage of many of the paintings that I’ve done and uploaded it — if you like it, you can buy fabric with this print on it here — and today got my order. Their “official” delivery date wasn’t until next week so I’m thrilled with how quickly they processed and shipped the order. It looks absolutely stunning. The colours are deeply saturated and the inks look like they’re embedded in the fibres rather than just floating on the surface. The quality is superb. I chose heavy upholstery fabric and Caitlin is going to be making a quilt out of it, but there are so many things I can imagine doing — an obvious example would be uploading photos of loved ones to make pillows and things like that, or even just using it for tapestries, as an alternative to posters for large-scale printing. Most of these images in my print were nice and high resolution, but there were a few paintings that were as low as 60dpi and even they turned out beautifully, with smooth lines and tones with no visible pixelation in any of it. I’m very happy with what I got from Spoonflower and definitely recommend them. Plus the price was great.

You can zoom in on this picture by clicking on it, and there are three close-up images after the break, all of which you can zoom in on as well.

(Continued)

An improved wget / http-get function using archive.org

I post this because it’s an obvious but I suspect often overlooked idea that may be useful to other internet programmers reading this. As you may know, I’m writing a bot that is used to convert old blogs into physical printed scrapbooks. As a part of doing this, it has to download all of the images that are referenced therein. As I’m sure is no surprise, when you’re talking about images that are more than a few years old, the links are quite often dead, and there’s nothing there but a 404 or useless redirect to download. However, there is a very good chance that you can find it on Archive.org’s supremely useful “Wayback Machine” which is an ambitious attempt to build a digital time machine by archiving dated snapshots of the Internet. I decided that it might be a good idea to integrate this into my http-get function, and what surprised me is how easy this was to do.

Here’s the meta-code:

   http_get($url)
      retrieve($url)
      if the retrieved data is 404 or otherwise invalid
         retrieve(http://web.archive.org/web/19950101010101/$url

It’s really that easy to create a function that downloads a URL, and if it can’t find it, checks for it on the Wayback Machine!

Specifically, what this does is attempts to download your URL from the standard location. The data retrieved could be “good”, or it could be a “404″ or other standard error, or it could be “bad” data. You’ll find that often expired links do not create obvious failures. An expired link often redirects to the site’s main index, or it may point at sites that are gone or have been completely redesigned and redirect you to any number of locations. Sometimes the easiest way to determine if the retrieved data is “valid” is by checking the file type. For example, in my case I was downloading only images, and if the URL returned anything other than an image I could be pretty sure that it had expired (since few redirect systems are intelligent enough to respect file type). You’ll have to come up with your own way of determining whether the data you downloaded is what you wanted.

If the data downloaded from the original URL is determined to be invalid, you create a new URL that starts with “http://web.archive.org/web/19950101010101/” and is followed by your original URL. So for example, if you were trying to download http://www.zentastic.com/shannon-larratt-is-zentastic.gif and it failed, your Wayback URL would be http://web.archive.org/web/19950101010101/http://www.zentastic.com/shannon-larratt-is-zentastic.gif. Now, that doesn’t mean that the Wayback Machine has to have a version of the file from January 1st, 1995 at 01:01:01. When you request a date that doesn’t exist, it will try and redirect you to the closest one it has. What it will do is give you a “302 Moved Temporarily” with the “correct” URL (which your http-get function should already deal with anyway). Download the URL specified in the “Location” field, and you’ll get the first version of the file stored by the Wayback Machine.

I should note that if you use the URL that I’ve specified above, what you’ll get is the oldest version of the file. The reason I did that is that I figured that if I’m trying to retrieve an old version of the file that is no longer at the URL, the oldest one had the best chance of being the correct one. If on the other hand you want to download the most recent version of the file, you can ask for it with a URL starting with “http://web.archive.org/web/20130101010101/” (ie. January 1st, 2013 instead of 1995). However, depending on the type of file and type of redirect in use, there’s a good chance that the Wayback Machine could be archiving the same junk data that you got and are trying to avoid in the first place. Alternately, if you know the date of the linking entity (for example if it’s a blog or forum post), you could also use that date.

Anyway, I found it was a very easy improvement to my standard http-get function that at least in some cases, improves functionality dramatically! Hope this was helpful to someone.

Rockets, Blimps, and Teeth

BECAUSE A STUPID FIRE ALARM IS GOING OFF, I COULDN’T PROOF READ THIS EVEN IF I WANTED TO.

WHICH I DON’T. ANYWAY…

A while back I made the offhand comment that “Paypal would fly you to space”, and what I was of course talking about there was that PayPal founder Elon Musk took the megamoney he made there and went on to found SpaceX. One of SpaceX’s vehicles is a rocket called the Falcon 9, which advertises a LEO lift capacity of 23,050 pounds (a hair over 10,000kg, or a little less than half the Space Shuttle, or a less than a tenth the size of America’s retired massive Saturn V rocket) and is their largest lift vehicle. More importantly perhaps, it is as I write this the most economical and competitive launch system (much to the chagrin of China’s Long March rockets which had hoped to compete). But what is that “cheap” price? The cost per full launch of the Falcon 9 is a minimum of $54 million, or over $5000 per kilogram to LEO. Frankly I am not impressed, but lets look a little closer at those costs.

First of all, the Falcon 9 is not currently reusable, and so can only be used once. SpaceX is naturally working to make the Falcon 9 reusable in the future because it should reduce launch costs. Elon Musk has said that with enough launches the cost per launch could be reduced by a factor of one thousand — which would be remarkable. Of course, he still has to pay off the $300 million in development costs on the Falcon 9, to say nothing of the costs of developing what sounds like a very expensive recovery procedure (the rocket uses a single engine to return to the launch site and lands bottom-down vertically after upper stage separation). I hope that happens, but it’s a difficult problem to solve, and until then, the cost stays at $54 million plus per launch. I was very interested to read that the kerosene and oxygen that the Falcon 9 uses is about $200,000 per launch. So only 0.3% of the cost is fuel — basically nothing. I find that shocking. But I suppose it’s not that different from a car — you spend $20,000 for the vehicle and then a few dollars to drive it a hundred miles. If you had to throw the car away at the end of every trip, either driving would cost a fortune. You’d have to either figure out a way how to reuse your car, or figure out how to build a car at a fraction of the cost.

It’s funny because in SpaceX’s brochure they describe their philosophy as “simplicity, reliability and low cost”, but even they admit that their production delays were caused by the enormous complexity of the project. Those of you (anyone?) who actually slog through these entries know that the 1962 Sea Dragon rocket which had launch costs at the low end of $59 per kilogram or $600 at the high end. Yet the best we can come up with today, sixty years later, is over $5000 a kilogram. Parts of the Sea Dragon design is similar to the Falcon 9 in that the first stage uses the same fuel mixture — kerosene and oxygene. However, the Falcon 9 uses a 3×3 cluster of nine SpaceX Merlin engines of 125,000 pounds thrust, whereas the Sea Dragon uses a ridiculously scaled up single massive 80,000,000 pound thrust engine. They did this not just for “true” simplicity, but also because from a cost point of view, it’s not significantly more expensive to build a big rocket engine than a small rocket engine — the raw materials are not the main cost. The entire Sea Dragon rocket is essentially just a big metal tube, built out of inexpensive sheet metal. Every cost is brought as low as possible, thus the term “Big Dumb Rocket” (which I’ve linked before).

As I mentioned, development work on the Falcon 9 was $300 million. The development cost of a similar engine, this one designed for 250,000 pounds of thrust (twice as big as SpaceX’s Merlin engine), including all testing was $60,000 (in 1966 dollars). Half of that was the cost of building the engine. The best part of the story, which I have to share, is how the engine was built:

“TRW farmed-out the fabrication of the engine and its supporting structure, less the injector that they fabricated themselves, to a “job-shop” commercial steel fabricator located near their facility . The contract price was $8000. Two TRW executives visited the facility to observe the fabrication process. They found only one individual working on the hardware, and when queried, he did not know nor care that he was building an aerospace rocket engine.”

The fuel tanks were fabricated not by some ultra-high-tech space contractor, like they are today, but by a commercial tank builder at a cost of a few dollars per pound of tank weight (a number which would be lower if done in-house of course).

It really drives me nuts. Low cost rocketry is very do-able. We’ve known how to do it since the sixties. And when I say “known how”, I do not mean theoretically like with Project Orion’s nuclear ships. I mean “known how” as in we built the technology and tested it. But as with all things that involved contracts between megacorporations and megagovernments, would they rather sell a rocket for $54 million, or would they rather sell a rocket for $250,000? I know we all know the answer. It really drives me nuts. I so badly want to see cities in space and when I look up at the moon I want it to look like the Earth at night, dotted with the lights of a thousand cities. Am I asking too much of humanity? It just seems to close, so possible, I feel like I can almost touch it.

Maybe my photoshopping is not so impressive but here is what the Earth looks like from the space station. After all, in my fantasy world if you don’t like the way the moon looks at night you can always just look at the Earth from the moon instead. I sure would like to live long enough to help make this a reality.

Everything I’ve mentioned so far in this entry is “down-to-earth” (pardon the inappropriate phrase) technology, but I did want to mention one other issue that’s a bit farther into the theoretical realm. But not so far that we shouldn’t have done it decades ago.

According to NASA, by the time the Shuttle has hit 1,000 mph (which it does in about a minute), it has consumed a million and a half pounds of fuel, or about a third of what it carries. After two minutes, the shuttle is up to 3,000 mph and the solid rocket boosters separate (each of which have over a million pounds of powdered aluminum and ammonium percolate). NASA has floated designs for maglev “rocket sled tracks” capable of accellerating a 500+ ton lift vehicle up to at least Mach 2, using — and this is very important — only currently existing technology. I’m not even talking about more abitious systems like the Star Tram or a Lofstrom loop which are capable of sled-launching cargo (including humans) into orbit using only the acceleration on the track. What I’m talking about is a simple launch assist system that we could build any day we will it. The cost of constructing such a launcher was estimated to be less than $100 million, or about a quarter of the $450 million average it took for a single Space Shuttle launch. I can’t wrap my head around why this wasn’t done. It really feels like a willful conspiracy to keep the costs as high as possible.

Not that willful conspiracies by the wealthy to defraud taxpayers is anything new. In fact, the historical record is such that I’d say that Occam’s razor pretty much demands it.

Finally, you may remember years ago I had a brief interest in the idea of lighter than air yachts, the notion of building luxury airships that would sit in the same market sector as yachts do today. So instead of taking your rich friends out on the sea, you’d go for a cruise over the rain forest, silently drifting fifty feet over the tree tops in a whisper-quiet electrically propelled and computer guided floating pleasure craft. I still think it’s a good idea. But it was brought back to mind when I saw pictures from a Russian 3D artist of a “vacuum ship”:

Blimps float because what they contain — helium generally — is lighter than the ambient air (just like hot air baloons float because the warmer air is the less dense it is). But what’s lighter than helium? The smart-alleck answer is “nothing”. “Nothing” as in literally nothing, as in a vacuum. There is nothing lighter than nothing at all.So that’s what this is. The problem we have is that a vacuum means that the totality of the surrounding atmosphere is crushing the chamber, and it’s extremely difficult to find a material that is strong enough to deal with those forces while still being light enough to float in the air. That said, his design is clever (and you could optimize it by floating a tensigrity balloon inside a geodesic dome) and might actually be more doable than he thinks (in the English translation you can see that he believes no suitable material exists).

Other than that as you can see I made some casts of my teeth (using fast-setting dental alginate to make the mold) to start building some prosthetics for fun. The neat thing is I can see the chips on the sides of my molars from when I bit my tongue barbells. I hate touching the stone/plaster material though, it feels like scratching a chalkboard. Speaking of, I don’t like touching chalk either. Hurts like crazy the way it stimulates the nerves. I’m not sure if everyone feels like that or not? The fire alarm in our building has been malfunctioning so Caitlin and I have had our sleep messed up a bit this week, plus we got food poisoning it seems when we ordered a pizza. Hopefully I am feeling better by Thursday because I’m getting tattooed.

AW FUCK THE ALARM IS GOING OFF RIGHT NOW!!!!!

ARRGHH! I’M GETTING TO HATE THIS BUILDING!

Something I made for lil’ Tony Stark

I did a test pour of pewter (so it’s not really “Iron Man”… more of a “Bismuth/Tin Alloy Man”) into the mold I made of a Lego mini-fig that I think turned out very nicely. I don’t know yet exactly what my plans are in terms of mounting (ie. necklace, keychain, whatever) and if I’m going to customize it, but I’m very happy with how the quality turned out. More pictures after the break.

(Continued)

Movie Recommendation: THE DIVIDE

Caitlin and I went to see “The Divide” today, and even though it’s getting — to my great surprise — really bad reviews from weak-stomached film critics, I want to give it my whole-hearted recommendation. I’m a big fan of post-apocalyptic dystopian movies, and I don’t think I’ve ever seen one this bleak and hopeless and generally depraved and upsetting. I swear I was stressed out from the beginning to the end of the movie… there’s a real claustrophobic desperate anxiety that just never lets up and things just keep getting worse and the story descends deeper and deeper into the most awful nightmare. If you liked “The Road”, well “The Divide” makes it look like a feel-good Disney movie. It’s a start-to-finish crushing dirge that I recommend seeing in the theatre because I worry that at home you might not be as trapped in its depression and your natural urge to emotionally survive would push you into the happy corners of your home, far from the scenes it’s breaking you with.

So yeah, go see “The Divide”. You will regret it, but you will thank me for the recommendation.

In much, much, much happier news, I wanted to share with you, with his permission, this amazing tattoo that my friend Karsten in Germany got of my “Owl’s Adventure” painting (which is currently hanging at Badur’s, and you can also get it as a shirt). I like that the artist laid in the yellow sun without an outline. Really love how it turned out!

Also in the pleasant news category, before we left for the movie we released the sparrow that we’ve been nursing back to health. As soon as we opened the roof on his prison-house he happily flew off, did a couple loops, and landed in a nearby tree. He looked great and it was a real joy to know that the effort paid off. I actually think it’s the first time that I’ve nursed a wild animal back to health and then released it into the wild (if you can even call Toronto “the wild”), and I have to say that it is a wonderful feeling. And seriously, if I had watched “The Divide” and not had anything wonderful in my day to offset it, I’m pretty sure I’d be slitting my throat right now.