Thursday, June 14, 2012


I just sat here, thinking how complicated a sail simulator really is; First there is wind. It has a general direction and force. Then there's the shifts. Shifts are puffs and lulls, lifts and headers moving down the course with a certain rythm. Any two boats experiene different wind unless they sail close together, and if they do, they will generate shadowing and bending. On top of that, there's local wind variations due to geography.
A good thinking spot
Then there's the waves. Waves vary in height and distance, and they travel. Just like the wind, the waves have a direction and a speed; Boat A and B meets the same wave at different positions, and if the depth is different, then the wave will be different in length, height and force. Waves typically become smaller on the lee side of an island. On top of that the waves attack the boat differently based on their direction relative to the boat direction. Waves from the bow are choppy. Waves from aft come slower and make you surf. Waves from the side make you roll.
The view from another good thinking spot
Currents add to the fun too. The current also has a speed and a direction. Both may vary. Typically the speed varies with the depth, and the direction changes with local underwater geography. The current may also vary in both direction and strength over time, - as the wind changes, or the moon generates tide.
A good sailing spot
All these things make racing more fun and more challenging, and guess what... all these things are actually in the WWC system. It is really a wind, wave and current simulator in itself. The WWC receiver and interpreter provide all the data needed to make a boat sail under all the above mentioned conditions. I guess that's why I love the Flying Fizz... It acts like a boat, and it has a sailing engine with full support for all the WWC features. Just add seaspray and you're virtually out there...


  1. tides tend to run in two directions and speed up dramatically in narrow channels, winds do interesting things on leeward side of land masses, like die down completely or create back eddies, winds will bend along land masses, often allowing one to sail a higher course closer to shore, waves running against tides get choppy, wind speed and direction variances, unless offshore, tend to be very pronounced. To say that wwc mimics all these things realistically is overstating its ability. Yes, wwc allows us to pixel sail and that is a wonder all by itself, but i wouldnt call it realistic. so far I would say nomads global wind system is the most realistic wind but it seemes to be mostly downplayed by the powers that be in the sl sailing comunity, which i suspect has more to do with entrenched teritorial protection than with what actually works the best. But then again what do I know, Im just another sailing noob

    1. Thanx Ronin. You made me reread the post and edit a few details. I am pretty sure the WWC system supports pretty much all the features mentioned; Wind, shifts, travelling waves and changing current including those automatic adjustments based on depth and location; Plus local variations and shadows and bending. The RD can even reverse tides mid-race, if she so wishes.

      The WWC is far from perfect, but it does make an effort to simulate a complete racing environment. I am really not sure how to make sense of a comparison with a wind-only system.

      In a forum far far away, I dreamt of importing real wind into SL. Back then people were busy telling me why it was impossible. I find it very interesting that such a system now exists.

  2. Ronin, without wanting to start a discussion and without belonging to "the powers that be" I have some problems with Global Wind in SL.

    - Most YCs have fixe courses and are not able to just switch around buoys if the wind isn't right.
    - Often the real wind is just too slow, in SL we ned some more oomph than in RL to keep things interesting.

    I'm pretty happy with the fact that we can create our own wind in SL and don't need to bother with calms, storms, and other nasty stuff. Same as the usual SL weather I want my sailing wind to be always perfect as well.

    And last but not least, the only really available Global Wind boat, the Nemo, lags many of us to death. I don't know if that has to do with the complicated communication between boat and off-world servers, and I don't care. It's all not really working out yet.
    When surfing the net I'll happily wait a few second for a server to respond, when sailing in a race I just can't afford that luxury.

  3. Ronin, I don't think it is a question of "powers" nor "territorial protection".
    Global Wind System and WWC are just incomparable system, because based on different approaches, different purposes. Comparing apples and oranges. Their only common denominator is that they provide wind.

    GWS provides a wind that comes from a RL weather station. Fine, it is "realistic" until the datas are formatted and computed by a server before they are sent to SL Boats (min. / Max., computed variations...). That same server may use a sort of map to simulate windshadowed areas due to terraforming. Where is it available but in Blake Sea? Who can define the effect of terraforming on that wind? When applied, the resulting wind has very few to do with the RL source wind. Furthermore, GWS doesn't manage current nor tides nor waves afaik.

    WWC gives all power to RDs (and boat builders to implement all features). WWC may simulate current, tides, waves, and also manage local variations. It does quite everything you describe in your post.

    That to say that in term of features, GWS doesn't compare to WWC, they are just incommensurable. But again, there are no comparaison possible:

    The main advantage of the GWS is not the "wind" by itself, but the possible features which could be (or are , for some, with Nemo) implemented into the external server, such as boat tracking, external computing of wind shadow between boats to reduce in-world processing and then lag, and so on. It is not only a wind system. It is much more (or may become), and that why this system is very interesting.

    Talking about wind only, the unique difference between GWS and WWC is the source of the wind: RL input for the GWS updated every 3 or 6 hours and shaped with an algorithm by an external server, or set by a RD for the WWC with an unpredictable shape for shifts. That's it.

    None of them is "realistic" in the term you describe, but GWS is "wind only" when WWC is "full weather system" (Wave, Current...), GWS is closed system, WWC is an open system, WWC is a weather system while GWS is more intended to provide additional feature to boats.

    If focusing on "RL" wind, it would be quite easy to add a script in the WWC, so that this script requests RL wind from a RL weather buoy and send a "race update" command to the existing WWC. (Some weather buoys provide real-time information). Using a percentage of variation instead of real input, may provide the best system ever seen, with the advantages of a full featured wwc and the advantage of "RL" variations. Easy to do.

    To summarize, I think there is a total misunderstanding of what the two systems are able to do, and certainly a misunderstanding of their purpose.

    Both systems do not compete (only boat builders do), and they should get profit of each other and converge.

  4. To be more acurate perhaps i should have said is that the global wind feels more realistic because of the greater variences in speed and direction than maybe RDs put into most of the races.
    I agree with Orcs that perhaps a minimum wind speed with the global be nice. My observations were mailnly that with the global wind it often pays to tack the windshifts because they are pronounced and last a while, and the gusts are great enough i can ride the curve. I find that with the races with wwc shifts are often too small and too short a duration to bother tacking. But that takes some of the fun out of it. To me that is part of racing and sailing in general. watch for and use the lifts and headers. And i wasnt really so much talking about the other features wwc has, was only talking wind and what to me felt, while sailing in it the more realistic. and yes its a system only the nemo uses, a boat im not that fond off. a dingy that turns like a mack truck. Wind is what we use to sail but in rl sailing wind is also what messes us up. When was the last time anyone here got knocked down in a gust using wwc. got knocked down twice in global in the nemo, huge grin, thats how it should be. In many races Rl there are moments of pure panic and bedlam. I like those, makes you act fast and decisive or your toast. Havent been here long enough to know who and what the powers that be are and to put that in perspective, i often have running battles and disagreements with the gods on a daily basis. They need to listen to me better and sometimes need to be reminded :))) also know little about what makes it all work here in sl, am not a tech type. and always was a bit fuzzy on the rules. My rules in rl use are more like, dont hit anything, dont get hit by anything and dont fall off. But have sailed for decades in all kinds of weather. single hand a 29 ft 80 yr old wooden gaff rigged sloop, block and tackle stuff. So its from that perspective that i speak about the global wind feeling more realistic

  5. About wind, I quite agree Ronin.
    I think the parameter "rate" of wwc can be a part of the answer, but is unfortunately very poorly or insufficiently used by RDs (in conjunction with shift values)

  6. The biggest problem with the wind in GWS, is that - at any given time - it serves the excact same wind to all boats. In RL shifts and gusts arrive at different boats at different points in time.

    That makes the GWS uninteresting for racing. Everybody gets the excact same header at the same time no matter where they are. So everybody tacks, and status will be quo at the next mark.

    Windvariations of RL can quite easily be synthesized. We can do that already, provided RDs learn how to.


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