SL Wind Variance Between Sims

[Madelaine McMasters]

Hi Kids!!!

Long, long ago, I built a one prim contemplation spot that depends on the intra-region variability of the SL Wind to create soothing (for me) and interesting  motion in clouds of particles. I enjoyed it for years at Forgotten City until something broke, and the wind blew uniformly across the entire region. My beautiful meandering cloud of stars became a boring, constant, unidirectional stream. I thought this was a system wide change, perhaps made by LL to conserve some tiny server or viewer CPU load. A few years ago, I rezzed my prim in a sandbox and was thrilled to find it working properly.

Yesterday, I rezzed it at "The Far Away" and found it "broken" once again. I immediately popped over to Ivory Tower and rezzed it, where it works just fine. I enabled rending of the Wind Vector metadata in both sims and saw what I expected. The image below shows vector data from The Far Away (left side) and Ivory Tower (right side). You can see the difference. And that makes all the difference in the world. I imagine regatta sailors would notice this, as regions with uniform wind would feel much different than those where they are highly variable in time and space.

Do any of you know if wind variability across a region is something that can be turned on/off by sim owners in some little known corner of an interface somewhere?

ICKY                                                                                        WONDROUS

To see why I'm so interested in this, here's a demo video of my particle cloud on a region with variable winds...

Rather than watch the entire five minutes, drag through the timeline to see a mini time-lapse.

Edited March 27, 2020 by Madelaine McMasters

[Ardy Lay]

I poked around and didn't find such a setting anywhere. 

I used to enjoy watching the Linden trees sway and shake in the wind.  I used to hear wind noise when sitting 60 meters up in a huge tree.  I suppose the changes we have noticed happened at different times.  I just looked at the wind vectors in Perry.  They are whirling around nicely.

 

Edited March 28, 2020 by Ardy Lay

[Rolig Loon]

Except for your video, which I have watched before with fascination, I haven't given a lot of thought to wind variations in SL. I created a wind vane for my own region years ago. It changes direction continually -- yes, I just checked -- but I don't have an easy way to tell how that direction compares to any other region's wind, since my estate is on its own isolated island.  I can't see any way to control it myself, much less turn it off entirely.

I notice in passing that there is still a setting in the Advanced menu that you can toggle from Fixed Weather to Variable Weather, but I think that's a setting that was deprecated years ago. I seem to remember playing with it in the past but never seeing that it had an effect. And it may or may not be relevant to your question, Maddy.

[Madelaine McMasters]

It's possible the wind is entirely viewer side, though the way it works appears sim/region dependent. I toggled "FixedWeather" and, as expected, nothing changed. All the regions in the vicinity of Dreamland North have the "problem". Mainland regions don't. I wonder if this is a private estate/mainland distinction.

ETA: You're right Ardy, Perry's winds swirl "correctly".

Edited March 28, 2020 by Madelaine McMasters

[TechDave]

In my effort to 'explore' winds of SL I created a Local Winds HUD (or object since it's modify). Was my first venture into scripting. 

When touched it local chats wind direction and average speeds at your position. 

Never tried setting several of them out (is copy too). Then clicking each to get variances between them. I was just interested in getting a idea of winds at my position. It worked with landing of my helicopter.  When testing I never seen 0m/s and direction varied as well. 

Edited March 28, 2020 by TechDave

[Madelaine McMasters]

13 minutes ago, TechDave said:

In my effort to 'explore' winds of SL I created a Local Winds HUD (or object since it's modify). Was my first venture into scripting. 

When touched it local chats wind direction and average speeds at your position. 

Never tried setting several of them out (is copy too). Then clicking each to get variances between them. I was just interested in getting a idea of winds at my position. It worked with landing of my helicopter.  When testing I never seen 0m/s and direction varied as well. 

I also learned about the SL wind via scripting long ago, creating a wind vane for my little island hut. It wasn't until I constructed a large radius particle emitter (which required a "trick" in the creation of particle textures) that I noticed the winds were variable across the region. You can see this variance by going to Developer->Render Metadata->Wind Vectors. Then move your camera so it's looking straight down and cam back until you see the little red vector lines (I inverted the image for my OP). If you're in a region with intra-region variable winds, the vectors will point in various directions with varying lengths (velocities). If you're on a region with a uniform wind, all vectors will be equal length and pointing in the same direction.

[Rolig Loon]

40 minutes ago, Madelaine McMasters said:

I wonder if this is a private estate/mainland distinction.

If so, recall that my region is private, not Mainland, and wind direction changes continually, but I can't swear to whether it is the same across the region.  I guess I'll have to test and see.

Edited March 28, 2020 by Rolig Loon

[Madelaine McMasters]

1 minute ago, Rolig Loon said:

If so, recall that my region is private, not Mainland, and wind direction changes continually.

View the Wind Vectors. In "broken" regions, all vector lines are parallel and of equal length. They will change direction and length over time, but they do so in unison. In "working" regions, the vectors move somewhat independently. I just visited a region that had two wind nulls with counter rotating winds building around them. This is the behavior that generates the curved and forked tails in my particle clouds. I've witnessed my cloud grow three tails, so I know regions can have at least that many little weather systems in them.

[Rolig Loon]

OK....  Here's my test.  I created an Anemometer with the following simple script:

integer iReport = -29881744;
integer iStart;

default
{
    state_entry()
    {
        vector Pos = llGetPos();
        string Loc = (string)((integer)Pos.x);
        Loc = llGetSubString(Loc,-5,-1);
        llSetObjectName("Anemometer" + Loc);
        iStart = TRUE;
        llSetTimerEvent(0.1);
    }
    
    on_rez(integer startup)
    {
        llResetScript();
    }

    timer()
    {
        if (iStart)
        {
            if (llGetUnixTime()%60  == 0 )
            {
                iStart = FALSE;
                llSetTimerEvent(10.0);
            }
        }
        else
        {
            llRegionSay(iReport,"Wind = " +(string)llWind(ZERO_VECTOR) );
        }
    }
}

and placed it in five objects that I rezzed in random spots around my region. As you can see, the script assigns a unique name to each object on rez and then sets its timer so that it will report the current local wind vector every ten seconds, synced to an offset equal to Unix time mod 60. Thus, all five of my objects will report at "exactly" the same time.( "Exactly", within the nearest second.)

Here is a set of sample results over a span of one minute:

[11:06] Wind Report: Anemometer175-- Wind = <9.39365, -0.49008, 0.00000>
[11:06] Wind Report: Anemometer164-- Wind = <9.39222, -0.49025, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <9.39098, -0.48870, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <9.39156, -0.49605, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <9.39453, -0.48739, 0.00000>

[11:06] Wind Report: Anemometer164-- Wind = <9.15360, -0.47765, 0.00000>
[11:06] Wind Report: Anemometer175-- Wind = <9.15502, -0.47751, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <9.15309, -0.48348, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <9.15589, -0.47485, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <9.15235, -0.47617, 0.00000>

[11:06] Wind Report: Anemometer164-- Wind = <8.91734, -0.46518, 0.00000>
[11:06] Wind Report: Anemometer175-- Wind = <8.91875, -0.46506, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <8.91961, -0.46243, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <8.91609, -0.46377, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <8.91697, -0.47102, 0.00000>

[11:06] Wind Report: Anemometer164-- Wind = <8.68342, -0.45283, 0.00000>
[11:06] Wind Report: Anemometer175-- Wind = <8.68482, -0.45274, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <8.68218, -0.45150, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <8.68568, -0.45014, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <8.68318, -0.45868, 0.00000>

[11:06] Wind Report: Anemometer175-- Wind = <8.45322, -0.44054, 0.00000>
[11:06] Wind Report: Anemometer164-- Wind = <8.45182, -0.44060, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <8.45058, -0.43935, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <8.45169, -0.44645, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <8.45406, -0.43797, 0.00000>

[11:06] Wind Report: Anemometer175-- Wind = <8.22391, -0.42846, 0.00000>
[11:06] Wind Report: Anemometer164-- Wind = <8.22252, -0.42849, 0.00000>
[11:06] Wind Report: Anemometer100-- Wind = <8.22128, -0.42732, 0.00000>
[11:06] Wind Report: Anemometer166-- Wind = <8.22250, -0.43434, 0.00000>
[11:06] Wind Report: Anemometer192-- Wind = <8.22474, -0.42593, 0.00000>

[11:07] Wind Report: Anemometer164-- Wind = <7.99549, -0.41651, 0.00000>
[11:07] Wind Report: Anemometer175-- Wind = <7.99687, -0.41651, 0.00000>
[11:07] Wind Report: Anemometer100-- Wind = <7.99426, -0.41541, 0.00000>
[11:07] Wind Report: Anemometer166-- Wind = <7.99557, -0.42235, 0.00000>
[11:07] Wind Report: Anemometer192-- Wind = <7.99770, -0.41401, 0.00000>

So, in a short test the wind vector varies considerably over time, but it appears to be the same at all five stations within 0.01 in both X and Y.  That is, I see no statistically significant variation within the region.

Edited March 28, 2020 by Rolig Loon

[Qie Niangao]

That looked like fun so I tried a quick-and-dirty little script to (almost) simultaneously sample an array of locations in the region, then took a tour of some Mainland regions. Unless I did something wrong it seems different wind directions and speeds were spread across each of these regions. The script:

default
{
    state_entry()
    {
        list sampleLocs =
            [ <64, 64, 0>,  <128, 64, 0>,  <192, 64, 0>
            , <64, 128, 0>, <128, 128, 0>, <192, 128, 0>
            , <64, 192, 0>, <128, 192, 0>, <192, 192, 0>
            ];
        vector pos = llGetPos();
        llSetObjectName(llGetRegionName());
        integer locIdx = llGetListLength(sampleLocs);
        while (--locIdx >= 0)
        {
            vector sampleLoc = llList2Vector(sampleLocs, locIdx);
            vector wind = llWind(sampleLoc-pos);
            llOwnerSay((string)((integer)sampleLoc.x)+","+(string)((integer)sampleLoc.y)+" from "
                +(string)((450 - (integer)(RAD_TO_DEG * llAtan2(wind.y, wind.x)))%360)
                +" at "+(string)llVecMag(wind));
        }
    }
    touch_start(integer total_number)
    {
        llResetScript();
    }
    changed(integer change)
    {
        if (CHANGED_REGION & change)
            llResetScript();
    }
}

Results:

Quote

 

[13:37] Spangle: 192,192 from 59 at 2.996514
[13:37] Spangle: 128,192 from 72 at 4.792066
[13:37] Spangle: 64,192 from 74 at 1.649434
[13:37] Spangle: 192,128 from 243 at 2.575971
[13:37] Spangle: 128,128 from 328 at 2.889071
[13:37] Spangle: 64,128 from 25 at 3.669423
[13:37] Spangle: 192,64 from 139 at 1.778782
[13:37] Spangle: 128,64 from 68 at 1.738316
[13:37] Spangle: 64,64 from 318 at 2.059889

[13:38] Malacosoma: 192,192 from 17 at 1.052966
[13:38] Malacosoma: 128,192 from 117 at 2.126717
[13:38] Malacosoma: 64,192 from 64 at 1.728377
[13:38] Malacosoma: 192,128 from 298 at 1.340276
[13:38] Malacosoma: 128,128 from 16 at 2.655983
[13:38] Malacosoma: 64,128 from 190 at 1.809999
[13:38] Malacosoma: 192,64 from 294 at 1.686910
[13:38] Malacosoma: 128,64 from 151 at 1.399544
[13:38] Malacosoma: 64,64 from 285 at 1.078870

[13:38] Tussock: 192,192 from 213 at 2.792427
[13:38] Tussock: 128,192 from 232 at 1.981718
[13:38] Tussock: 64,192 from 58 at 2.088820
[13:38] Tussock: 192,128 from 183 at 1.609678
[13:38] Tussock: 128,128 from 245 at 2.751805
[13:38] Tussock: 64,128 from 184 at 0.545264
[13:38] Tussock: 192,64 from 152 at 1.631125
[13:38] Tussock: 128,64 from 93 at 3.545127
[13:38] Tussock: 64,64 from 243 at 0.598216

[13:38] Anilis: 192,192 from 36 at 1.901986
[13:38] Anilis: 128,192 from 355 at 1.781564
[13:38] Anilis: 64,192 from 47 at 3.259238
[13:38] Anilis: 192,128 from 79 at 1.501139
[13:38] Anilis: 128,128 from 272 at 2.199456
[13:38] Anilis: 64,128 from 70 at 1.802516
[13:38] Anilis: 192,64 from 358 at 1.978734
[13:38] Anilis: 128,64 from 63 at 0.837682
[13:38] Anilis: 64,64 from 77 at 1.719781

[13:38] Tenera: 192,192 from 261 at 2.678334
[13:38] Tenera: 128,192 from 284 at 4.329994
[13:38] Tenera: 64,192 from 10 at 4.203663
[13:38] Tenera: 192,128 from 42 at 1.291852
[13:38] Tenera: 128,128 from 261 at 2.215320
[13:38] Tenera: 64,128 from 177 at 2.732882
[13:38] Tenera: 192,64 from 127 at 1.424777
[13:38] Tenera: 128,64 from 113 at 2.921265
[13:38] Tenera: 64,64 from 79 at 3.559516

[13:38] Foxglove: 192,192 from 285 at 1.752974
[13:38] Foxglove: 128,192 from 226 at 2.010959
[13:38] Foxglove: 64,192 from 259 at 2.418503
[13:38] Foxglove: 192,128 from 226 at 2.133502
[13:38] Foxglove: 128,128 from 204 at 3.671405
[13:38] Foxglove: 64,128 from 244 at 0.773044
[13:38] Foxglove: 192,64 from 221 at 2.342159
[13:38] Foxglove: 128,64 from 214 at 2.876477
[13:38] Foxglove: 64,64 from 200 at 2.961532

[13:38] Epirrhoe: 192,192 from 134 at 2.202018
[13:38] Epirrhoe: 128,192 from 316 at 1.852990
[13:39] Epirrhoe: 64,192 from 290 at 1.643891
[13:39] Epirrhoe: 192,128 from 223 at 2.391884
[13:39] Epirrhoe: 128,128 from 280 at 7.895977
[13:39] Epirrhoe: 64,128 from 278 at 2.590425
[13:39] Epirrhoe: 192,64 from 174 at 2.217868
[13:39] Epirrhoe: 128,64 from 197 at 1.989657
[13:39] Epirrhoe: 64,64 from 65 at 3.243810

[13:39] Tuliptree: 192,192 from 97 at 5.986525
[13:39] Tuliptree: 128,192 from 127 at 3.260000
[13:39] Tuliptree: 64,192 from 191 at 1.572163
[13:39] Tuliptree: 192,128 from 158 at 1.655186
[13:39] Tuliptree: 128,128 from 248 at 1.606440
[13:39] Tuliptree: 64,128 from 212 at 4.697158
[13:39] Tuliptree: 192,64 from 194 at 1.597089
[13:39] Tuliptree: 128,64 from 6 at 1.593346
[13:39] Tuliptree: 64,64 from 200 at 3.764330

 

 

[Rolig Loon]

Fascinating, @Qie Niangao!  So it looks like @Madelaine McMasters hypothesis may be right.  My private estate appears to have the same wind vectors everywhere, but the Mainland regions you sampled don't. Q.E.D.

[Ardy Lay]

http://wiki.secondlife.com/wiki/Category:LSL_Weather

[Ardy Lay]

http://forums-archive.secondlife.com/139/68/146384/1.html

[Rolig Loon]

Thank you, Ardy.  So, the difference between my results and Qie's may have less to do with the fact that my region is private and Qie was sampling Mainland than has with the fact that my region has no immediate neighbors. The behavior that Maddy is asking about is a result of edge effects between regions, if I understand Andrew Linden's comments.

[Qie Niangao]

22 hours ago, Ardy Lay said:

I used to enjoy watching the Linden trees sway and shake in the wind.  I used to hear wind noise when sitting 60 meters up in a huge tree.

I remember trees moving, too, enough to dig in a bit: Turns out there used to be a viewer debug setting, RenderAnimateTrees, that disappeared from the wiki between 11 October 2011 and 6 February 2012. They apparently nerfed it in viewer release 3.2.5 in order to address its effect on FPS.

There's still an AudioLevelWind debug setting; can't say for sure but I suppose it still works.

[Madelaine McMasters]

I've been darting all over SL, and I think Ardy's got it. Isolated regions have homogeneous winds. Regions with only diagonal neighbors (no shared edges) have homogeneous winds. Any region that shares edges with one or more other regions will have complex wind patterns.

The "turbulence" seems proportional to the number of edges a region shares with others. So, the idea spot for my contemplation spot is a region with four adjacent neighbors. Kitty corners don't count.

Edited March 29, 2020 by Madelaine McMasters

[Lindal Kidd]

This would explain why SL sailors always encounter ridiculously variable winds...because they very seldom sail in regions that have no shared edges with other regions.

Which also explains why all the sailboat software "engines" have a built-in capability to ignore SL winds and set a constant wind direction and speed.

[Drake1 Nightfire]

TIL there is wind in SL... I need to find a hang glider that works.. 

[Lindal Kidd]

Drake, there are three kinds of hang glider (or indeed, any glider or sailplane)

• The kind that is basically just an attachment and an animation when you yourself fly.  You have complete control over whether you go up or down with the normal flight keys
• The kind that doesn't respond to any sort of lift, or up or down flying commands, but just has a fixed glide ratio.  The higher the place you jump from the further you go.
• The kind that has an actual simulation of lift...thermals, slope, and/or wave.  These may allow you to make conditions "easy" or "hard" via HUD settings, or may rely simply on random chance.  I think at least one of these systems claimed to make use of terrain and SL wind conditions.  Not sure I believe it.  Or maybe my piloting just stinks.

[Valentina Kendal]

A couple of you mentioned making wind vanes/ I would like to make a wind sculpture for a friend that mimics one she owns in RL. She lives on mainland with neighboring sims.  Could any of you point me to a wind vane script I could use to start out my job (I have minimal scripting skills)?  I didn't see anything obvious in the scripting library or MP. Thank you! Contact me in world if you need Valentina Kendal.

[Mollymews]

4 minutes ago, Valentina Kendal said:

I would like to make a wind sculpture for a friend that mimics one she owns in RL. She lives on mainland with neighboring sims.  Could any of you point me to a wind vane script

a place to start is with Dora's script

// wind bag script, Studio Dora, Dora Gustafson 2008-03-21
vector rotAxis = < 0.0, 1.0, 0.0 >; //the direction the object points, when not rotated
vector wind;

default
{    
   state_entry()    
   {        
      llSetTimerEvent( 5.0 );
   }    
   
   timer()    
   {        
      wind = llWind( ZERO_VECTOR );    
      if ( llVecMag( wind ) > 0.125 ) // if well defined then        
         llSetRot( llRotBetween( rotAxis, wind )); // turn object axis in the wind's direction    
   }
}

 

[Valentina Kendal]

Well, that get's me pointed in the right direction...literally. Thanks