Freesteel Blog » Weekends
I’m going to do some other coding, now that I got this result. The code would fall apart if I touched it again.
Next on the list of things to do is clear out the vast quantity of rubbish left in the code, completely redo the subdivision loops and make the logic robust, apply it to multiple z-levels and plot slices, then make it test against edges and faces (not just points), and package it into a self-contained (but very slow) version of the slicer.
I don’t know how long this will take, as there are many other distractions available.
Thursday, November 6th, 2014 at 1:08 am - Hang-glide
Just when I thought it was over for the summer, there came a chance to go flying at Llangollen. It seems there are more hang-gliding conditions this year than kite-surfing conditions, which is not what I’d hoped.
Wednesday, October 22nd, 2014 at 3:02 pm - Weekends
How does anyone hold down a proper job?
I just got a “Hello world” program working out of a pair of Jeenodes kicking around in the cardboard box left over from the Housahedron project before they migrated to Berlin. Of course, there was no documentation for how to plug in the interface into the Jeenode, and I had to get Adrian’s help.
Friday, October 3rd, 2014 at 11:55 am - Kayak Dive
Aside from having to get up at five in the morning and Becka not skiving the day to come along on the boat, it was a perfect trip out.
Liverpool is starting to look a lot like the Esbjerg did the first time I caught the ferry over to Denmark in 2003 and saw spinning wind turbines everywhere.
What amazing kit — the original gopro camera still hasn’t broken. I record these videos for the same reason I write phone numbers down in a book or keep a trip log: I can’t remember things well enough.
The water was pretty warm at 16degrees. I wore all my layers under the drysuit anyway and barely felt a thing swimming around. It was like a dream. I didn’t take any lobsters, but the others did. The conger eels stayed in the cracks while the tompot blennies came out to play.
The second dive was on the Calcium where there was one large cod and more starfish than grains of sand.
There was a surprise party in the evening, which I thought was for my birthday, but wasn’t.
I’ve always hated fell walking. It’s character building, good for a family trip out, and uses lots of time. It’s boring. As a kid you’d rather spend the day on the beach building sand castles or learning to windsurf.
Yes, there are so-called wonderful views. But they’re not the point. If they were, then how come the walk doesn’t get cancelled when the hills are in fog? We don’t try to windsurf when there’s no wind.
Admit it, you’re doing it because of tradition and for the pointless exercise. It’s a particularly painful exercise because you’re only using the lower half of your body, pounding it for hour after hour with hardly an interval of rest. At least when you go cycling there are those downhill bits where you cover the ground and your muscles have time to recover.
The idea of the Lakeland 3000 is to walk all 4 peaks in the Lake District that are over 3000 feet in altitude in 24 hours. This is a stupid idea, but that doesn’t stop people from getting hooked on it, and then inviting Becka and me into the plan. It was the caving conference weekend. The caving conference is always the same each year. One thing lead to another, and I found myself walking towards Keswick town square at 10:30pm on a Friday night after an extremely grumpy day due to a headache and no sleep the night before.
Wednesday, September 10th, 2014 at 2:28 pm - Kayak Dive
We went away for some kayak diving in Pembrokeshire over the weekend. I wanted to dive on the north coast from St David’s, but the north wind had picked up, so we directed ourselves to the south coast and going out of Solva after camping on Friday night in a layby to the east of Felindre Farchog on the A487 that had bogs. A useful discovery after drawing a blank going down some of the single-track back roads near there at one in the morning.
There’s not much to report on the diving. No amazing sights. Not a conger eel, or dolphin, or trigger fish, or even a spider crab. It was mostly kelp, gravel, silt, and a few pollacks. Everything had gone away for the winter even though the water was as warm as it is at any time of the year. The energy for life comes from the sunlight, not from heat. The cliffs were empty of birds who had abandoned their ledges that they had spent the spring and summer painting white with guano.
Solva harbour is pretty dry most of the time. After waiting 5 hours for the tide to rise, we dragged our boats out when it was at this level.
Becka is unimpressed by this strap coming loose on to which she had tied her canoe for this dive on the south side of Green Scar. There were gusts of wind on all sides of the island, even on this seaward side which was supposed to be sheltered. We did a shallow short dive, then got back on the boats and paddled into the wind to get back to the coast. There had been a slight concern we weren’t going to make it after going off-shore like this, but there wasn’t a problem.
We camped at Cairfai Farm, the low-carbon tents-only campsite south of St David’s on the coast, having left our kayaks on the beach so that we only had to carry the empty tanks up the steps to change them at the car.
My old set of electronic charts are broken, but after looking at a chart of Ramsey Sound on the wall of a pub I spotted a wreck in Porthlysgi Bay which I could look up accurately on the internet, which meant we could dive the wreck of the St George the next day.
I don’t know anything about it, except there were a lot of tall bits of metal which Becka had to thread the kayak anchor line around.
After this, the options were to either drift round on the current into Ramsey Sound, or go back along the coast for a final dive off the east side of Porth Clais where there was a deep section of sea bed close in shore, according to the charts (about 13m).
Being chickens, we opted for the latter. I’d also told the coast guard we’d be off the water by 6pm, so there wasn’t much time left. I always inform them now after getting call-outs due to walkers who see us fall in the water and start thrashing around trying to get our kit on before appearing to drown.
It was a long drive home via the chip shop in Fishguard. I still need to come back and do that north coast again when it’s in shelter.
Friday, September 5th, 2014 at 12:56 pm - Hang-glide
I got a lot of other more important things I should be blogging about, but what the heck. This is a quick one and I want to relive it. I got out yesterday for a flight on Whernside and persuaded a caver to carry up my harness for me and make sure there wasn’t a crash on take-off because, as usual, I was pretty much alone again.
A paraglider did walk up just as I was ready to take-off. Unfortunately he didn’t join me in the air for very long after he launched half-way down the face of the hill to avoid the wind-speed.
This is the fifth time I’ve carried my glider up this hill. It’s doesn’t feel very far now.
Classic British method of rigging with the glider flat on the ground.
The air was very murky, but actually blowing on the hill properly for a change. I got up high 400-500m above take off three times.
This is about 8 minutes later after I lost my altitude and was now below the ridge again. I don’t have enough experience to tell whether this was my fault through incompetence, or whether it was unavoidable. That’s one reason to have other people in the air.
I had to pack up early, and flew straight out from the ridge against the wind to land just the other side of Low Sleights Road by Ribblehead, which was not bad going. I cannot get over just how barren and bleak this landscape is.
Is it all because of the sheep, because otherwise it would be a total forest — as it is inside any enclosure?
I did get a very short canyon trip with an even shorter rope before expo was finished.
The canyon was called Salza Stauseeabfluss, and it went from the dam on the lake from Grimming. The rope was labeled at 80m, but no one had noticed it had been cut at 36m when they picked it up. We had to descend down the wall of the canyon in three stages off trees. We also got the walk out spectacularly wrong, and ended up clawing our way up a 60degree grassy slope in the dark.
This was on the same day I had a very nice 3 hour flight off Loser totally alone (due to west wind predicted) with a relatively low cloud base again, and tactically squeaked through the pass into the Bad Mitterndorf valley knowing that there was a good landing field there which I had used a week earlier.
Unfortunately every single field including this one seemed to be full of tractors cutting and bailing hay. Fortunately, a bird appeared and showed the way up to the clouds after 15 minutes of barely maintaining height.
That’s one of the lessons from the 50k Or Bust Book: both time and place matters. Use your arithmetic to know that a slow descent rate of 0.2m/s is only 12m a minute (or 120m in ten minutes), which means you can stay in the game for long enough for the next thermal to rise.
Because the clouds were low, I didn’t want to stray up into the mountains, and stayed close to the valley where the lift was scratchy. The predicted winds were never materialized and I belly flopped on my landing again.
Here I am looking to the Grimming. If conditions this year had been equal to last year I would have got beyond it into the Enns Valley and maybe around to the Dachstein. This is the big target.
The annoying thing about flying is how quickly a good flight wears off on you. I was already fidgeting the next morning as though I had achieved nothing the day before.
Becka said something very mean to me last night: “You seem a lot more dissatisfied with life since you took up hang-gliding again.”
This needs sorting out. My original notion had to be to treat hang-gliding like skiing, where you go abroad on holiday to the appropriate place and do as much of it as you can to get it out of your system, and then come home and get on with normal life. But it’s not quite working out like that.
The final flight in Austria was in rough conditions and didn’t go anywhere, but the landing was perfect, like I was on autopilot.
Then the weather became rainy and normal for Austria, and we were into the depressing phase of bringing things down the hill and tidying up after expo.
We got away from the campsite at 5am in the drizzle and caught the 10pm Dunkirk ferry to Dover, although I did insist we stopped at the McDonalds in Zweibrucken because that’s where the previous car stranded me for two days in May.
It was the highlight of the journey.
It rains and rains and just won’t stop. It’s also gotten pretty cold and I’m having to wear all my clothes that aren’t damp from lying in the tent. The last day of warm sunshine was six days ago where I stood on takeoff for 2 hours as paragliders wafted past and went down in the totally dead air of that day.
See the smile? I want more flying. Some canyoning would be good too, but it ain’t going to happen on this trip.
When I finally took off I flew in a direct straight line across the valley beyond the highway and golf course, and then had to walk 5 miles back via an ice cream stand to Base Camp for a lift back up the hill, after which I drove down, fetched my glider, and drove back up again for the walk up to Top Camp (the Stone Bridge).
Here’s the outside view of Top Camp:
And this is the inside:
It’s both a rock and a hard place with nothing in between, but it is still better than tents because it is larger, cavernous, and not like a box of damp fabric that progressively rots things as each day passes.
I dropped into the far end of Tunnockshacht down to the new connection to Arctic Angle. Becka was away with the Austrians on a different expedition and couldn’t warn me that it was going to be an unutterably deep one. That wasn’t the problem. The problem was getting terrifyingly stuck in a U-bend crawl while weaseling around the C-leads waiting for the guy with the drill to rig a rope traverse along a ledge of an undescended shaft to access the phreatic continuation. Then we surveyed about 100m until it crapped out, and hauled ourselves back out by 2am.
I forgot to take any pics, so here’s a photo of a nosy horse’s nose:
On Tuesday I went to the newly discovered Balconyhohle. (The horizontal entrance is from a ledge within the side of a hole.) I was cold and had to keep eating. We killed a couple of going leads there too, but there’s enough unexplored ways on to keep this one spreading further underground. This has been the big find of the expedition. It’s a lot of work to keep up with the mapping.
Here’s a picture from the walk back to the carpark from Top Camp in the morning:
Since then I’ve been working on the Adaptive Clearing stay-down linking killing the bugs one at a time while all my HSMWorks buddies have been at a big planning meeting in Copenhagen this week. It seems like an endless grind. Anyway, I don’t plan to go there again, and the ferry between the UK and Denmark is being terminated this September.
One of the things that crashes the system is when the A-star linking can’t find a way to connect from point A to point B, and spreads out through every single cell in the dense weave until it runs out of memory.
One obvious solution is to generate a weave that has a wider cell spacing and solve the routing issue in it, but this is too complicated. I worked out another way, which is to deny it access to most of the interior cells of the fine weave that are nowhere near the boundary or on the theoretical direct line route. The A-star algorithm is so powerful that it will find a way round, even though the domain would look so much more complicated. This initial result becomes the starting solution for the linking path, on which the PullChainTight() function is called. This is actually a bad name for it. It should be called RepeatedlySpliceStraighterSectionsIn(), but this discription wouldn’t remotely be so compelling to the imagination.
This will get implemented only if absolutely necessary. The thing about the linking routine is that it does not need to work 100% of the time, because it can always fall back to the old way of retract linking, which is what everybody puts up with right now, so it might not be worth expending too much effort for the last 2% of awkward cases where the reliability is going to be questionable anyway. In software development the trick is to know when to stop.
Time to work on some cave surveying software today. Maybe I’ll get a flight in tomorrow. Hope so.
Saturday, August 9th, 2014 at 8:16 am - Hang-glide
A week of sulking and being neglected by Becka while she went caved solidly came to an end yesterday when the weather broke and I got a four hour flight from Loser back to the Grimming, where I got to last year.
It was almost carbon copy of my 3 hour 2013 lucky flight, but this time I had better gear and I knew what I was doing — which was good as the conditions have been far more demanding in terms of low cloud base and scarcity of thermals below 2100m.
Here’s the picture in 2013:
Here’s the picture now in 2014 with comfy neoprene bar-mits, an airtight harness that actually fits so I can stretch my legs and fly at the right angle, and an android phone running the astonishing XCSoar with its automatic zoomed in thermalling mode. The helmet and cheap sunglasses remain the same:
Here’s the flight track with the Grimming on the right followed by a long uninterrupted glide towards home:
Becka came along and shared a pizza with me while I rigged.
Every time I do this I have to pinch myself that this is even possible.
A tandem glider pilot gave me a 75% chance of getting up in the conditions. I let him go first to spot the lack of thermals for me, and barely survived when he went down in the initially cloudless conditions. Once I was high and conditions had developed I was able to fly cloud to cloud while deep in the mountains.
I could have gone far if I wasn’t so obsessed with getting to the Grimming where I got swarmed by sailplanes.
The phone with XCSoar comes with a camera that’s better than anything else I own. I can take pictures with it if I don’t get too distracted or do something stupid like stall the glider trying to get a shot of the horizon. Here’s a picture of the Loser Plateau where Becka has been caving.
We zoomed in to one section, and this is plausibly the tarp protecting the entrance of the stone bridge bivi cave.
The cave was extended with a connection made to a smaller cave this year, and the total system is now 104kms in length, making it the second longest cave in Austria. When I get bored with flying, maybe I will go back to doing more of that. I do need to work on the cave drawing software a bit more.
Meanwhile, at the machine tool work, the bugs and crashes are being reported at a fast pace. I have got to get this working 100% by October. That’s the deadline I have set myself.