Second Life Forums Archive - Client Ghosting

Desmond Shang

Guvnah of Caledon

Join date: 14 Mar 2005

Posts: 5,250

11-08-2006 08:02

This may be better asked elsewhere, but I'm not sure if the scripting forums are quite right either (the question goes deeper than that and into 'how SL works').

I have sim-crossing trains - nonphysical scripted vehicles in Caledon. Once you get past all the puffing steam, all they really use is a simple global position update to move around.

Sometimes when crossing sims, a 'ghost car' or 'ghost engine' is left at the sim border. It's not the train itself - that happily keeps chugging along. The ghost train remains, and if I relog it goes away. Convincing me that it is a clientside effect, or maybe something to do with my view of the train, or dropped packets or... something.

I want this problem to go away! Does anyone have any idea how?

Thanks in advance,

Desmond

_____________________

Steampunk Victorian, Well-Mannered Caledon!

Aislin Keynes

Registered User

Join date: 27 Apr 2006

Posts: 67

11-08-2006 10:29

Not being a technical person I have no idea why this happens, but I'm curious also. It can be quite annoying when racing and you swerve to miss a boat that is not even there. I don't think that we can make it go away however, we just have to live with it.

Patchouli Woollahra

Registered User

Join date: 3 Nov 2006

Posts: 24

11-08-2006 10:36

The ability to seamlessly transition between sims with barely a moment's pause, or any seizing up of scripts, for loading is a little miracle that happens millions of times a day in Second Life. Little oddities like these happen when the handover between sims isn't fully reflected in your local cache. This happens because bulletproofing such handovers isn't worth it isn't worth the added load on the servers, as opposed to simply paying a little attention every now and then to clean up items that have moved out of a sim.

Don't worry too much about it. The server eventually notices what's happened and derezzes it whether you relog or not.

Aislin Keynes

Registered User

Join date: 27 Apr 2006

Posts: 67

11-08-2006 11:05

Thanks Patchouli

So it is on the server and not client side. That being the case, should you not be able to see your own ghost? I never have but always wondered why.

Llauren Mandelbrot

Twenty-Four Weeks Old.

Join date: 26 Apr 2006

Posts: 665

11-08-2006 15:27

I`m pretty sure that [nearly] all "ghosts" are client-side phenomena resulting either from packet loss [the viewer never gets the message that the avitar/object is no longer there] or bugs on the server [the server never sends the message in the first pace]. If I am correct, one cannot ever see one own`s ghost, because one`s own client already knows that the avitar is elsewhere.

That said, I suppose that the issues we have been having with the Presence systems could occasionaly result in a server-side ghost. Such ghosts would eventually "just go away" when the invalid information gets overwritten by up-to-date information. If this kind of error were to occur with a object, on the other hand, the ghost would never go away, and would instead be as real as the original object was, as there is no source of outside information to correct the situation.

....unless someone is better informed than I?

_____________________

ninjafoo Ng Says:
November 4th, 2006 at 7:27 am We all love secondlife so much and were afraid that the magic will end, nothing this good can ever last…. can it?

Desmond Shang

Guvnah of Caledon

Join date: 14 Mar 2005

Posts: 5,250

11-08-2006 16:08

I'm hoping one of the grid-wizard residents will read this, and bestow upon us mortals some digital blessedness.

Is there a way to prevent or reduce ghosting of nonphysical, scripted objects when they cross sims?

The ghosted train cars seem like they are there, but there are no collision effects, the original train chugs on intact, and the 'ghost' is gone to anyone that relogs.

Help please!

A haunted Desmond...

_____________________

Steampunk Victorian, Well-Mannered Caledon!

Dr Tardis

Registered User

Join date: 3 Nov 2005

Posts: 426

11-08-2006 16:33

From: Desmond Shang

I'm hoping one of the grid-wizard residents will read this, and bestow upon us mortals some digital blessedness.

Is there a way to prevent or reduce ghosting of nonphysical, scripted objects when they cross sims?

A prim or object dissapearing is sent out just once from the sim to the viewer... the problem is that it can get lost on its way to you (it's a big Internet), and if that packet gets lost, there's no recovering it... hence, ghosted object.

Short answer is: no, we can't do a blamed thing. Long answer is: it's theoretically possible, but something the Lindens will have to do after they've fixed the other bugs out there.

Client Ghosting
Desmond Shang Guvnah of Caledon Join date: 14 Mar 2005 Posts: 5,250	11-08-2006 08:02 This may be better asked elsewhere, but I'm not sure if the scripting forums are quite right either (the question goes deeper than that and into 'how SL works'). I have sim-crossing trains - nonphysical scripted vehicles in Caledon. Once you get past all the puffing steam, all they really use is a simple global position update to move around. Sometimes when crossing sims, a 'ghost car' or 'ghost engine' is left at the sim border. It's not the train itself - that happily keeps chugging along. The ghost train remains, and if I relog it goes away. Convincing me that it is a clientside effect, or maybe something to do with my view of the train, or dropped packets or... something. I want this problem to go away! Does anyone have any idea how? Thanks in advance, Desmond _____________________ Steampunk Victorian, Well-Mannered Caledon!
Aislin Keynes Registered User Join date: 27 Apr 2006 Posts: 67	11-08-2006 10:29 Not being a technical person I have no idea why this happens, but I'm curious also. It can be quite annoying when racing and you swerve to miss a boat that is not even there. I don't think that we can make it go away however, we just have to live with it.
Patchouli Woollahra Registered User Join date: 3 Nov 2006 Posts: 24	11-08-2006 10:36 The ability to seamlessly transition between sims with barely a moment's pause, or any seizing up of scripts, for loading is a little miracle that happens millions of times a day in Second Life. Little oddities like these happen when the handover between sims isn't fully reflected in your local cache. This happens because bulletproofing such handovers isn't worth it isn't worth the added load on the servers, as opposed to simply paying a little attention every now and then to clean up items that have moved out of a sim. Don't worry too much about it. The server eventually notices what's happened and derezzes it whether you relog or not.
Aislin Keynes Registered User Join date: 27 Apr 2006 Posts: 67	11-08-2006 11:05 Thanks Patchouli So it is on the server and not client side. That being the case, should you not be able to see your own ghost? I never have but always wondered why.
Llauren Mandelbrot Twenty-Four Weeks Old. Join date: 26 Apr 2006 Posts: 665	11-08-2006 15:27 I`m pretty sure that [nearly] all "ghosts" are client-side phenomena resulting either from packet loss [the viewer never gets the message that the avitar/object is no longer there] or bugs on the server [the server never sends the message in the first pace]. If I am correct, one cannot ever see one own`s ghost, because one`s own client already knows that the avitar is elsewhere. That said, I suppose that the issues we have been having with the Presence systems could occasionaly result in a server-side ghost. Such ghosts would eventually "just go away" when the invalid information gets overwritten by up-to-date information. If this kind of error were to occur with a object, on the other hand, the ghost would never go away, and would instead be as real as the original object was, as there is no source of outside information to correct the situation. ....unless someone is better informed than I? _____________________ ninjafoo Ng Says: November 4th, 2006 at 7:27 am We all love secondlife so much and were afraid that the magic will end, nothing this good can ever last…. can it?
Desmond Shang Guvnah of Caledon Join date: 14 Mar 2005 Posts: 5,250	11-08-2006 16:08 I'm hoping one of the grid-wizard residents will read this, and bestow upon us mortals some digital blessedness. Is there a way to prevent or reduce ghosting of nonphysical, scripted objects when they cross sims? The ghosted train cars seem like they are there, but there are no collision effects, the original train chugs on intact, and the 'ghost' is gone to anyone that relogs. Help please! A haunted Desmond... _____________________ Steampunk Victorian, Well-Mannered Caledon!
Dr Tardis Registered User Join date: 3 Nov 2005 Posts: 426	11-08-2006 16:33 From: Desmond Shang I'm hoping one of the grid-wizard residents will read this, and bestow upon us mortals some digital blessedness. Is there a way to prevent or reduce ghosting of nonphysical, scripted objects when they cross sims? A prim or object dissapearing is sent out just once from the sim to the viewer... the problem is that it can get lost on its way to you (it's a big Internet), and if that packet gets lost, there's no recovering it... hence, ghosted object. Short answer is: no, we can't do a blamed thing. Long answer is: it's theoretically possible, but something the Lindens will have to do after they've fixed the other bugs out there.

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Client Ghosting