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lucagrabacr

LL and TPVs should have region crossing prediction turned off by default, it gives bad first impression on most users about SL exploration

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To those who are not familiar with what region crossing prediction is, it's basically the thing which most of the time makes your vehicle seems as if they're flying around or phase into the ground on region crossings. 

The intent behind the feature was good as to make region crossings more seamless but it does exactly the opposite, making the idea of SL exploration a joke to many people who are unaware of the effect being caused by the feature.

Literally almost everyone I know don't know what this feature is, what it does and that it can be turned off, and many of those people just think it's just lag, giving mainland and the idea of mainland exploration an even worse unfounded bad reputation than it already has.

So many people don't know that SL has connected mainland continents, roads and oceans, and so many people think that "mainland is just laggier by default" which is a technical myth that's somehow sustained over the years, and having people think vehicles would just normally go flying around on mainland adds up to the misinformation about mainland and SL exploration. I wish LL and TPVs would have this setting turned off by default :(, what do you guys think?

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I didn't know it could be turned off.

What's the behavior of region crossings with it turned off?  And, assuming it's better behavior than the default, how do you turn it off?

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19 minutes ago, Lindal Kidd said:

I didn't know it could be turned off.

What's the behavior of region crossings with it turned off?  And, assuming it's better behavior than the default, how do you turn it off?

Probably under the Developer menu in FS. Might be under Advanced menu. Personally, I won't be turning it off. If ti's what I"m thinking it is, it definitely improved sim crossings. Which are not the same thing as region crossings, obviously.

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Posted (edited)

Firestorm has the "Movement at region crossing" setting in Preferences/Move & View/Movement.

With "Predict" set, at a region crossing your viewer will continue to show you or your vehicle moving at the velocity (speed and direction) it thinks you were following, based on what it last heard from the previous simulator before it disconnected, until it hears from the new simulator, when it will snap you to the position and velocity the new simulator tells it. If the length of the inter-sim hiatus is significant, and you weren't moving perfectly horizontally when you left the previous region then you will be shown ploughing into the ground of flying off into the sky until the viewer gets updated with the information from the new simulator.

With "Stop" set, your and your vehicle come to a dead stop at the border, and stay there until the new simulator updates your viewer with your position and velocity.

It's a matter of taste, I guess, which is preferable. When the simulator handover is fast the prediction option gives you a smoother, more seamless experience than stopping. When the handover takes ages the stop option prevents the flying off into the wild blue yonder experience.

How, or if, these settings relate to the other problems experienced at region borders, I have no idea.

I seem to remember playing with something similar in the SL viewer but can't remember the details.

Also, I'm not anywhere near technically savvy enough to claim this is a definitive explanation. It may even be hopelessly wrong.

ETA: There's Velocity Interpolate Objects and Ping Interpolate Object Positions settings in the Developer/Network menu, which I think may be related to this.

Edited by KT Kingsley
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I'm the author of the "stop at region crossing" code. Technical background here.

Short version: There's a fundamental problem, that region crossings take time, during which the object is frozen in place. And there's a bug; the very last  update sent to the viewer by the sim that's giving up the object has velocity and acceleration info which contains poor quality data.

Those are both server side problems. Ones LL is unable to fix. We can try, in the viewer, to hide both problems from the user by guessing what the data ought to be. Available guessing approaches are

  • Just extrapolate blindly what was happening before the object left the sim. (Old behavior, and Firestorm in "Predict" mode). OK for slow boats, terrible for fast land vehicles.
  • Stop the object on screen hard during the region crossing. (Firestorm in "Stop" mode.) The pause is annoying but there is no bogus motion on screen. Drivers like this, sailors do not.
  • Extrapolate blindly, but with a time limit (Current LL viewer behavior.) Prevents the worst effects while keeping the sailors happy. Evenly distributes the misery.

I agree with Luca on this. Start out new users in "Stop" mode, which is understandable, and tell sailors how to get "Predict" mode for a peaceful slow sailing experience. Or at least set the default timeout in the Linden viewer to something small, like 100ms.

(I've done about as much as I can do until LL fixes some server side bugs. Fancier viewer side prediction algorithms might help, but fixing the bad data that comes out of the sims would help more. Meanwhile, if you want to experience a smooth drive, set "Stop" mode, get a car from one of the demo rezzers of the car builders in Burns and drive around Heterocera. You will have smooth region crossing experiences, but a momentary hold at each crossing. I'm done with this for now, until LL fixes some bugs. I once said to Oz Linden at Server User Group, "You guys fix the sim side problems and we'll take care of the cosmetics". Between what viewer devs can do in the viewer and what vehicle builders can do in vehicles, we can make region crossings look and feel good. But we cannot make them not break. That's on LL.)

 

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Lest we forget, motion prediction is quite common for almost every MMO out there. If you were to stop on every bit of positional data packet missed, your gaming experience would be very jittery, and overall dreadful. Region crossing motion prediction is essentially no different from that (albeit taken far more to the extreme, of course). So, tl;dr, I kinda like the behavior. :) 

Region crossing are still, by themselves, problematic (like too many disconnects); but that's really a separate issue.

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I agree, I prefer the motion prediction behaviour as well.  The newer behaviour ends up feeling like stop-start-stop-start all the time.  I appreciate the thought and time going into trying to make it seem better but for me it really doesn't.

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3 hours ago, animats said:

but fixing the bad data that comes out of the sims would help more.

Isn't it rather about lack of data than bad data?

I haven't really looked at this myself since I'm not a programmer but Whitecore claims to handle. If I understand right, their solution is to make the sim aware of its surroundings so it can keep handling objects and avatars effectively for a short time after they've left the region.

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3 hours ago, animats said:

I'm the author of the "stop at region crossing" code. Technical background here.

 

for SL vehicle enthusiasts, animats link is well worth reading

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Posted (edited)
10 hours ago, Lindal Kidd said:

I didn't know it could be turned off.

What's the behavior of region crossings with it turned off?  And, assuming it's better behavior than the default, how do you turn it off?

It's under "Move & View", and as someone already explained in the post it basically stops your vehicle for a bit depending on how heavy the vehicle is in term of script / complexity if the thing is set on "stop". Good vehicles usually cross in around or less than 1 second, but most vehicles don't cross that fast. The feature is great when it works as intended, but most of the time it just sends vehicles flying around clientside for a few seconds.

Interesting to see people who prefer the prediction feature turned on, because every explorer I've met prefer it being turned off once they know they can.

I'll post a gif showing a comparison of a vehicle's behavior between when it's turned on and off.

Edit: Here's the gifs

Prediction turned off in slow speed: https://gyazo.com/13db14e124a06487b9355cf2b3381b66

Prediction turned on in slow speed: https://gyazo.com/1f6945e7a12f2196ca6925284b774e60

Prediction turned on in high speed: https://gyazo.com/27a67619e5d7bd7210a9ef442010ad1a

And this test was done with a well-scripted car, most cars on SL use the ACS script which is much heavier than this and usually takes longer to cross

Edit 2: Maybe if it can be made so when someone's on foot, then prediction is turned on, and when someone's in a vehicle (sitting on an object) then the prediction is turned off, then it would be a great compromise (with the option for those who like them always turned on being able to turn it on at all times, of course)

Edited by lucagrabacr

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I've had mine set to "stop" for a while now, and find it very useful for walking in areas with nasty region crossings, like near my home in Bay City (which sits at the intersection of four regions). With the default set, my poor av goes flying the minute I step out the door of my house, but with "stop" set, I have a little hesitation, then continue walking smoothly. 

I can't speak to its effectiveness on vehicles, since there is nothing that can improve my awful driving. 

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8 hours ago, lucagrabacr said:

Prediction turned on in high speed: https://gyazo.com/27a67619e5d7bd7210a9ef442010ad1a

Thanks, Luca.

That's what motivated me to work on this problem. You can see that the last movement update, the one that gets extrapolated, is bogus. That car was going along smoothly. If the predictor kept it going in the viewer in the same direction with the same rotation while the region crossing processed, it would look OK. But it's clearly extrapolating from bad data, and the car flies into the air and rolls. Or seems to. That's a viewer-created illusion. It leads people to make frantic steering corrections. Then they crash. The "Stop" setting stops that, but rather abruptly.

This is embarrassing for Linden Lab. Really. They've had that bug since at least 2013, and haven't been able to fix it. A clip like that really shows how bad this is. Modern video games do not do things like that. This is the sort of thing that gets "Your game sux" comments from new SL users.

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Unless you spend your time in SL driving about in vechs, the default setting is the best.

SL's physics handling for vechs is so janky right off the bat that, personally, I have no idea why people devote so much time to it. Anyone who thinks it's even mildly acceptable needs to take 5 minutes out and play something other than SL.

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Posted (edited)
4 hours ago, Gadget Portal said:

Of course, if LL were actually interested in giving us decent service, this wouldn't be a problem. 

That's not fair.

I've lost count how many times I've been mad at Linden Lab for not delivering the quality they ought to but I've never ever doubted their good intentions. I know for a fact that all LL employees and contractors involved with Second Life genuinely love SL and only want to do what they think is best for this virtual world.

Edited by ChinRey
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11 minutes ago, ChinRey said:

That's not fair.

I've lost count how many times I've been mad at Linden Lab for not delivering the quality they ought to but I've never ever doubted their good intentions. I know for a fact that all LL employees and cotractors involved with Second Life genuinely love SL and only want to do what they think is best for this virtual world.

I'm with you on this but it still doesn't explain how LL manages to fall flat on its face far more often than not. Track records speak volumes and LL's record is not good. Never has been. And going by past history, never will be.

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I don't think that's fair either.

SL is a complex mess of multiple overlapping systems, each presenting its own caveats and scaling issues. LL's platform priorities and development strategies are not always obvious from the outside, nor are the causes and solutions to problems we see. There's also a very strong tendency to connect a personal failure of expectations with LL.

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Posted (edited)

Just did about a 30 minute run on the Mainland, trying with it both on and off. Driving with it on made driving more enjoyable for me than with it off. Generally. But I'm happy I now have this option, as it obviously can be very handy at times. I will surely be using it when I need to.

I see this as very useful for those who tend to crash into peoples' living rooms and front yards as well. I suggest you try it.

Tested with low-lag JFC bike (not ACS/KCP).


Should it be made default? Although I can see the point for it, I'm leaning towards "no".

Also, great work Animats.
 

Edited by HeathcliffMontague
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