## Freesteel Blog » 2013 » March

Tuesday, March 26th, 2013 at 9:44 pm - Machining

## Perpendicular unit vector frame in 3D

Let’s begin with what a unit vector is, and let’s not get sloppy. If we can’t be bothered to do this right, then what does it say about our other more advanced geometric algorithms?

I’m a computational geometry programmer, and I don’t like to type, so my 3D point class is defined like so:

```class P3 { double x, y, z };
```

I don’t think much of a special type called vector3 that is exactly the same thing, except you can add two of vector3s together, but you can’t add two P3s together. This sort of excessive type separation is annoying, serves no useful purpose, and is often promoted by the same folk who think that any attention to the detail of making correct unit vectors is not important — even though it actually does make a difference to the end calculation as well as the functions you might use to separate and optimize different cases.

Sunday, March 24th, 2013 at 4:11 pm - Cave 1 Comment »

## The Large dig enlarges

Update: Video included at bottom

The supposedly dire snowy weather didn’t seem to get in the way of attempting another dig in Large Pot. It did, however, put enough folks off that Neil’s plan for three waves into the front actually ended up being a trip with two and a half people (Beardy had to leave early). The only compromise was we had to get changed down in Masongill and walk up the road for an extra half an hour, rather than start at the foot of the track. This turned out to be a good thing given the howling winds and complete lack of shelter, which wouldn’t have fun trying to change in when you are wet.

As usual, it’s quite a long trip to get in and out to the dig face, and some of my repairs to my wetsuit since the zip broke last trip have been questionable. Not too much water had dribbled into the dig, so it was quickly cleared not long after I got the kayak pump and pipe to work, having taken in a knife, screwdriver and jubilee clip. The crinkly pipe broke again as soon as we were done with it.

Three people is enough to work the dig. A fourth person gives the third person some company while they are throwing mud up the slope, or backwards over their shoulders as I was, to get it out of the way as each digging tray of mud gets tipped out. It would be better to cycle through the positions more often, but you never feel like wanting to as it’s such an heavy crawl to get in and out once you’ve got stuck in to your job of either digging, hauling or throwing.

The trip in its entirety is like that too: another hour of digging is always easier than an hour of getting yourself back out the cave, so it’s tempting to put it off. And we could because I had brought a couple of bottles of lucozade for liquid energy to make a change from those thirst-making chocky bars. Neil thought it would make a good product placement photo, except you couldn’t see the label for mud.

So here is the state of the way on now: very tantalising, but still can’t see how far it goes.

It was getting late, and a real drag to get up and out of the dig.

Turns out, a lot of it has to do with the sheer weight of clinging mud.

This is the before and after cleaning self in the trickle of water from Colossus pitch.

I had a semi-waterproof fleece on the outside of my wetsuit for some extra warmth, and it was like stripping off a chain-mail vest in terms of its weight.

It was so cold and late outside we skipped the pub. Neil whizzed off, and it was all I could do to dial for Becka’s parents with ham-fisted numb fingers to see if I could stay there and get fed. I could barely work out what I was trying to do.

That evening, I was scrubbing the mud off my brand new Olympus “Not Very” Tough TG-2 camera, and the corner appeared to be missing — on its very first trip. This has got to be a record, even for me. You’re supposed to be able to drop this baby 2.1m onto a brick floor, yet a gentle mud wash and no apparent bashing around, had finished it off.

Humph!

I’m not getting on too well with this buying flash gear on the basis of now having a salary. Doesn’t seem to make things work better.

And the damn thing seems to be taking movies in this stupid “Windows Live Movie Maker”-incompatible MOV file format, so I can’t edit the clips easily. In the interests of researching the potential for cloud enabled products, I am attempting to edit it using the online YouTube editor. Unfortunately, you need to upload about a Gigabyte of unedited videos before you can play, so the results will be delayed if they work at all.

Update:

Got the video we had edited up:

Wednesday, March 20th, 2013 at 12:32 pm - Machining

## Watching the CEO 20% of the time

Friday, March 15th, 2013 at 12:18 am - Hang-glide

## In the air at Bradwell again

I work hard for my flying. I waited for a day at the freezing cold airfield where nothing was going on because it was too windy (I left Liverpool at 7:15am, before the instructor makes his determination of the day at 8:15am), working on some machining code and attempting to procure a parachute. Afterwards, I drove up to Hathersage to spend a comfortable night at Becka’s aunt’s house, because Becka was not around to tell me not to. We watched the new pope getting poped (stunningly unceremonious for such a ceremonial office), and decided that the Wikipedia article was a lot more informative than the BBC.

The hang-glider had been put into their garage overnight. Packed hang-gliders are a bit shorter than they were in the old days because the aluminium poles no longer extend along the entire leading edge. Instead the last metre is a formed by a white fibreglass pole called a wand that you lever into place. I am always concerned about losing these things, so I checked I still had both of them in the batten bag when I fetched it in the morning. I got away to the site by 8:30 and drove up the extremely narrow Duper Lane until I hit a snow drift. It was quite crusty and happened to be in shadow, while most everything else had melted.

I dumped the glider and harness off on the side and reversed all the way back up the lane and parked in the village of Abney. Then I cycled back to the spot, locked the bike and walked with the harness on my back with the glider’s detachable base bar and bag of battens in my hands. With a glider weighing about 30kgs and over a kilometre of carrying, every gramme of weight you can take from it matters. Clever, eh?

What wasn’t so clever was taking a wrong turning at the T-junction to the right on Brough lane and walking a kilometre in the other direction towards a mobile phone transmitter nowhere near the edge. After a phone call to confirm directions, I hiked to the correct place, dumped my stuff and went back for the glider. On the way I passed the first wave of paraglider pilots with their far more practical single backpacks of lightweight gear. By the time I humped my glider to the hill there were scores of them, and still more coming. The air was going to be crowded.

But that didn’t matter to me, because you know what? I only had one white glass fibre tip wand in my bag. God damn it. I took the remaining one on my walk back and asked everyone I passed if they had “seen one of these”? No they hadn’t. I went all the way back along the track where I had gone in the wrong direction, taking hours and getting sweaty because I was wearing Becka’s padded sallapetes. Nothing there. Then I went to the bike where I had originally dropped off the glider from the car. Nope. So, nothing for it but to go back to the hill and pack up. Grumble.

Then I saw it standing up in the snowdrift after the third time I had walked past it. I will never let this happen to me again because I will amend the batten bag so it is impossible for the things to slip out.

Meanwhile, it was dark and horrible out on the front. Half a dozen competition paraglider pilots had got up and gone over the back heading for the coast in very windy conditions. Headbangers, the locals said, as they called it a day. I rigged with a sense of doubt. Might as well as I was there.

Suddenly, the wind dropped off and became smooth as I carried to the edge. It felt completely right — which gets me nervous because I am used to things feeling wrong.

And it was completely lovely. Not a thing in the sky to worry about or dodge around. That’s got to be rare. Harness was too short to zip up due to a combination of wearing walking boots and the extra platform at the foot that I had neglected to remove.

Don’t know how high I got as I am still using my 20 year old vario instrument, having promised myself some fancy gear that’s modern and acts like a sat-nav so you don’t have to rely on your bad judgement. That’s my hope.

When the sun came out, the wind died temporarily (according to the direction of the smoke from the wood fires in the valley), and I came down. It was all too easy and clean. I don’t understand it.

Maybe it’s the glider being incredibly nice. That’s always possible.

I packed, tramped up the quagmire of a path up the hill, rode my bike to the car, drove all the way round, and got ready for the five hour long tedious drive down the M1 towards Cambridge. Why did they build that city so far away?

Wednesday, March 13th, 2013 at 12:19 pm - Kayak Dive

## Nothing much happening

So, it’s been a week since Becka left for China. Not a peep of news from her. I’ve taken to kipping in a sleeping bag underneath the duvet because it gets so cold at night. Nothing much else going on. She’s taken my camera with her, so not so easy to do snapshots. An awful lot of clearing up has been going on. I can now see the floor in the garage in most places. There’s even a designated corner for hanging up wet muddy things after a weekend. I worked out how to deal with the backlog of knackered drysuits — by cutting along their seams to flatten them out in anticipation of using the square metre-age of neoprene for insulating something.

The week of octopush playing was really hard work, especially the Manchester Octopush Tournament. As you can see from the results, we came back with a trophy. It’s a big beautifully carved wooden spoon. Apparently we’ve won it before, and the club managed to get it put on display in the glass cabinet in the university sport centre. You’ve got to look closely at the engraved word on the silver plate in the middle to know that it says “loser”.

That was Saturday. Sunday morning was a trip out to Rock Ferry to test out the club boats for the Easter Cornwall trip.

After making petrol smells all over the boat, nothing happened with the engine, so it was all a waste of time. Which was the point. We would have looked pretty stupid with a non-working boat in Penzance harbour.

There was quite a current flowing over this shallow slip and I accidentally fell off the side because the water was so cloudy. Luckily I scrambled back up before getting swept away and looking really stupid with no boat to rescue me.

Thursday, March 7th, 2013 at 12:08 pm - Weekends

## Becka goes to China

Last Saturday I bid farewell to Becka at the start of her 6 week caving holiday to Wulong in China. By the time I got home from the airport she was already on the Skype getting bored at her stopover in Helsinki.

So much for that whole lump-in-the-throat parting show at the gate, I thought.

Saturday, March 2nd, 2013 at 12:37 am - Whipping 1 Comment »

## Scary stuff going on in the gov

I remember the old days of awesomely crap government IT projects procured for billions of pounds that always failed after going three times over budget, then got covered up along with their contractually obligated fail-safe profits for the corrupt IT consultants — who then repeated the process having successfully claimed that anyone who said it could be done any other way was beardy hippy whom you should take no notice of. Funny how the stereotype of a computer expert was usually a beardy hippy.

Mr Liddell-Grainger: The Government set up a project called True North… Does anybody know what it did? The Cabinet Office gave the okay to £83 million to set up a project called True North, which was to paper sleeve a deal with Government. It has gone somewhat wrong. The only reason we came across it was because the company sued the Government for £24 million, saying that they were plonkers and they did not know what they were doing… Do you think it is farcical that we have got to the stage where you cannot get papers, we cannot get papers? The Government are covering up projects that have gone wrong to the tune of £83 million —- and that has been a snip compared to some of the things they have messed up. Are we just getting to the stage where this whole thing is becoming a farce?

…It does not seem to work. You have portals everywhere; you have websites; you can go in one way, another way. How on earth we are going to have an ID card system that is going to work, if the Government itself at the highest level cannot even get a project right?

…Who should be in charge of this? Do you know what the total assets of the Cabinet Office’s computer resources are? £122 million. That is more than the asset value of all the buildings they have in Whitehall, believe it or not. We cannot find out what they are. Do you have any bright ideas? Why has the Cabinet Office got £122 million worth of computer assets? They wrote off £52 million last year in depreciation. Either there is an awful lot going on that you do not know about and I do not know about and we do not know about, or one heck of a mess has happened and we are not sure whether it has or has not.

Mr Collins: Again, it is hard to get information. There is usually quite prolific documentation in the early stages of the project about its benefits but they do not publish result implementations. There are some examples. The DWP is probably one of the biggest. They announced to Parliament that their modernisation/computerisation of benefits would cost, I think, £713 million and would save 20,000 jobs, but at the last count it was £2.6 billion and the number of staff involved had increased. There is a magistrates’ court system called Libra, which was announced as being a £140 million project. At the last count that was £390 million. But it is hard to get information on costs, because they revise contracts.

So, what’s going on now in this same Cabinet Office?

Well, the money finally ran out, and the expensive do-nothing consultants could no longer be afforded, leaving no option but to hire the programmers directly and take on board their profit-reducing rationalizations related to actually getting stuff done.

And now there is code, visible, being produced, that you can see does something.

The URLs are all pretty cool. That’s the front doormat of any website. Go check out their blog and be amazed.

Here’s my favourite bit:

What we learned

…We also learnt about the benefits of agile software development – starting small, getting user feedback early and iterating fast based on evidence of real need.

To give a small example of a possible many: before the beta several of us thought a WYSIWYG text editing interface would be essential for departments to format their content. But by building working software and unleashing it early we discovered that editors quickly came to like the simplicity of markdown and, a year on, more than a hundred people around Whitehall are happily using it. Developing something more complex would have been a waste of time.

I’ve often had arguments with dogmatists who think that programmers and users are separate classes of people whom it is desirable to prevent comingling. However, this last statement cannot be true. Nobody develops complex WYSIWYG editors any more when there are enough of them out there that you can install for free. Someone must have been far-sighted enough to keep that type of rot out.

The real reason to shun WYSIWYG editors in favour of markdown technology (like the kind you find in Wikipedia) is that (a) they obstruct touch typing and other performance improvements that come with practice, and (b) they are fundamentally incompatible with end user computing, which is where the real enhancements are going to take place.

is twofold: (a) Their human performance is slow