What causes Prop Pox (and how to avoid it)

[fe_lipe]

That's my first post and topic on SC4D, but not because of a good thing, hehe   


I had a CAM I downloaded by torrent, but as I saw that there were an original version - and I could get support in case of trouble - here at SC4D, I started to update my SC4, downloading the original CAM and also downloading CAMelots, brand new props and mega packs I had never seen.

That was ok until I experienced prop pox. It happened with some lots but I just noticed when I built a seaport with PEG Seaports. They became completely empty, but they had always functioned perfectly. At first I thought it was some kind of duplicate prop pack or model file, or even some files conflict, but I did some research and discovered that.

I saw there's no turning back and it'll remain the same, and I'm kind confused about what to do, as I saw that prop pox it's not so common. May I look for the 'cause of the problem, delete it and start a brand new region ?

I appreciate any kind of help, 'cause this region is amazing, and I've been planning a CJ... 

[Diggis]

I've moved this to the correct forum.  I would suggest you read through this thread, especially the first posts by Bap.  Unfortunatly, if you really do have the POX there is currently nothing we know of that will fix it.  I would suggest checking if you have the BDK file from Pegs, and if so post a bug report at his site because he doesn't post here.  I would also suggest removing that file from your folder (and probably any others that rely on it) so you don't get the pox again, until a fixed file is forthcoming.

[jmyers2043]

if you really do have the POX

Diggis makes a good point ... "if" ...

They became completely empty, but they had always functioned perfectly. At first I thought it was some kind of duplicate prop pack or model file, or even some files conflict, but I did some research and discovered that.

I would not necessarily jump to conclusions. Do you have your detail set to max? Do you have other lots affected - such as residential?

[fe_lipe]

Diggis : Thanks for replying (and moving it to the right topic) ! 

Well, the description of POX it's exactly what happened with my game, but I might check it.

I do have BDK. I'll delete it and see what happens.


jmyers2043 : I had some problems with slow game and crashing, so all my configuration is set to low or medium. I'll check that anyway.

In fact, the most part of my lots had missing props. But even new lots that grew with props, lose them when restarting SC4 or even reloading the city.

Anyway, BDK may be the problem. I'll delete it, read the entire topic, see what I can do. I'll tell you later.

Thanks for helping!

[fe_lipe]

I deleted BDK file and now props aren't vanishing (I think so...). I tested it with a 350,000 pop. city, but I'll test with other big cities btw... Thanks guys !  

[teddyrised]

Hi all,

I really don't know where to start. Okay, maybe I'll start with a little problem that I have faced.

It has been around 4 years since I last played SimCity 4, and recently a long summer vacation motivated me that I should do something to rekindle my love for this game. I dug through the attic and found the installation CD (yea, that's so Jumanji), installed it on Windows 7 and everything has been fine so far.

It wasn't until recently, around a week after I have started a new region, that I realized props are systematically missing from my cities. Each save only further propagates the problem and nothing seemed to have stopped it:



One thing I realized was that when the prop pox first reared it's ugly head, the most recently grown/plopped lots were the first to be affected. However subsequent saves also reveal missing props in other parts of the city, propagating each time a save is made.

I googled for the issue and landed on this thread. In fact, I was lurking around SC4D for a very long time but didn't muster the effort to register a proper account.

It took me an entire night to go through all 21 pages of the forum, and I have to say that you guys (everyone that has helped to diagnose the issue in any way) have gone beyond your personal moral obligations and responsibility to make prop pox a recognized bug and more importantly, proposed ways to diagnose the problem and fix it, if there's anyway possible.

On behalf of every single person who have came along this thread's way and left with a better idea of what prop pox is and how to prevent it from recurring in the future, I salute every single one of you. Despite a famous BATer's bogus claims of a witch hunt turned onto him and his defiant insistance that we were out there to frame him, you guys treated insults and taunts with a pinch and salt and continued working as hard as ever to help every single one who came here seeking for advice and solutions.

Thank you, thank you, thank you. Just so much.

Although my region couldn't really be saved (I'm more of a perfectionist and would do anything, including starting all over, to make my cities perfect), I just want to let you guys that I have learned a very important lesson - not only about how the game works and the numerous flaws in Maxis' propriety game saving system, but also about human nature.

You guys just saved my ass, in short. At least I didn't have to continue building the infected region with a false hope that nothing is wrong (as claimed by a certain someone, hah). I have removed the problematic file and will be more than confident then ever that I'll build a better region

Thank you, guys *bows* 

(Edit)
Anyway, perhaps it was the stubbornness in me, I found a backup copy of my region that was made several days back. I forgot that when I backed up the SimCity 4 folder in My Documents I backed up the Regions folder too

The backup was done before I installed the certain someone's problematic file, so I'm very sure that any of the cities are prop pox-free to start off. And to make things a little sunnier, I always have DuskTrooper's mod that blocks all Maxis buildings on (but I only installed the R$, R$$ and R$$$ block files). Since the problematic prop modified by the certain someone is perhaps limited to residential lots (correct me if I'm wrong), my cities should by right be unaffected by the prop pox.

My assumptions turned out to be real. I played a few cities, and constructed massive suburban sprawls and plopped the Maxis gazebo like a madman (it has one of the highest prop count per grid unit, at around 20+ props per square). I let the game run for around 50 years because sleepiness got the better of me. I saved the city and I loaded it after exiting to region.

It's prop pox free.

I double-checked using wouanagaine's SC4Save tool, and by investigating the props subfile (which is at 18421848 bytes, or approximately 18.4mb) shows that the city if pox-free (no buffer overflow or whatsoever).

But I might be wrong, I'll continue testing my city and see how it goes, maybe let it run for 200 years or something.
Looks like it's for real. The umbrella prop only appears on Maxis residential lots. If you have disabled their growth completely, your city should be prop pox free (i.e. salvageable) if you can find a backup of it before you plopped the certain someone's lot.

* * *

My conclusion is that if you have DT's maxis building blocking mod installed at the start of the game, and have backed up your cities before you plopped any of the certain someone's problematic lots, then your backup should not be affected by the prop pox in the future too.

(/Edit)

[FrankU]

So, that's where we stand.

There is one file recognised as a cause of Prop Pox. So we are not going to use that file anymore.

But what if you have a region that never contained that file but even so shows signs of infection? I happen to have such a region. I uploaded already the first city from this region that was affected to RippleJet. I hope he is able to find my cause of Prop Pox.
But in fact it should be nice to know what kind of props could be the reasons and then find a way to identify them.
My pluginsfolder contains 2GB of lots, props, buildings and textures. And I'd like to start a hunt for the prop pox virus. Who can give me hints? What files or kinds of files are definitely not the reason, so that I can count them out?

[Fluggi]

Hello guys,
I'm a little bit confused. I tried to get the pox in a test city.
This is what I've done:

• I made a lot with many props on it and plopped it massively in a completely empty test city. I found a threshold:
  2862 of those lots and the subfile 2977aa47 of the saved game had a size of 4,102,010 bytes, 2868 let the size grow to 16,007,843 bytes.
  So there, the game switched the way of saving the game.
  
• I made a time controlled prop and gave it the TGI of a static Maxis Prop, so I had a replacement mod. I put this Prop on a lot.
  
• I put this lot without the replacement mod in the test city which had a small subfile and saved it. With this lot inside, the subfile was still small.
  
• I restarted the game with the replacement mod in my plugin folder. On the lot with the Maxis prop, there was now my prop. I saved the game.
  
• I restarted the game and plopped some more of the lots with many props on it and saved the game, it made the subfile grow to 16,208,667 bytes.
  
• Now I expected to have the pox. I restarted the game and loaded the city again, but every prop was where it should be.

Is there anything I did wrong?

[catty]

Is there anything I did wrong?

Its been a while since I read the Prop Pox topic, but from memory ... its also how many LOTs are affected as well, in the case of the know affected props they are beach props, but maxis also used them in low wealth (R$) houses as garden furniture so they can appear hundreds of times in your city.

hope that's right

[RippleJet]

• I restarted the game and plopped some more of the lots with many props on it and saved the game, it made the subfile grow to 16,208,667 bytes.
  
• Now I expected to have the pox. I restarted the game and loaded the city again, but every prop was where it should be.

We've had a few pretty strong indications that, for the prop pox to appear,
some of those props that have been modded need to be deleted during the process where the prop subfile surpasses 16 MB in size.
(btw, 16 MB = 16,777,216 bytes).

All savegames of poxed cities that I've inspected have a number of deleted props
(indicated by the flag saying it's an active prop having been reset to 0) in the end,
and it's among these that the subfile becomes corrupted.

Deletion of a prop would normally occur when a growable lot upgrades in the game.
Plopping new lots in empty space would never lead to the deletion of existing props.

This in turn would also explain why the prop pox doesn't strike every time,
and that you do have a chance of getting past those 16 MB without being poxed.

I uploaded already the first city from this region that was affected to RippleJet. I hope he is able to find my cause of Prop Pox.

I just realized I never posted anything about it after I checked your savegame, Frank...
The main reason was that there was very little to report...
The corrupted occurred very late in the prop subfile, with only half a deleted prop record following after the point of corruption.
That prop was all zeroed out though, with no information about which prop it could have been.

Since the prop pox clearly has affected a huge number of props along the eastern edge of that city,
it is clear that the prop subfile has become very much truncated at some stage.

[FrankU]

Hi RippleJet,

Sorry, but I don't understand.... Do you have any clue what might be wrong or not? Is there anything I can do? Do you want me to send you the second poxed city in that same region?

[RippleJet]

Sorry, but I don't understand.... Do you have any clue what might be wrong or not? Is there anything I can do?

To be honest, we've kind of run out of options in the whole prop pox matter...
The more I look at different poxed cities, the less I know about why it became poxed.

The only thing common for all of them is that a corruption occurs in the end of the prop subfile,
and that all records that follow after that point (and have an invalid starting point) are marked as deleted.

Some times those deleted props still have their TGI addresses intact, but mostly not.
And often the whole prop subfile is truncated, so that most deleted prop records are in fact deleted (I hope that makes sense...).

I believe the only certain way of finding additional pox causing props,
would be to go through the same lengthly and tedious process that bap used when identifying those four we now know of.

Do you want me to send you the second poxed city in that same region?

Sure, I can take a look at it, but don't expect too much out of it...
I will be travelling most of next week though, so I won't be able to look at it until next weekend.

[BarbyW]

One way to check out using bap's method needs to concentrate on original files from before the release of the file that has been identified as causing the problem. It should be done with as few files dated after that as possible and from what we have already noted needs to concentrate on props used on Maxis R$ and R$$ early stage lots.

[FrankU]

Hi RippleJet and BarbyW,

If I interpret your posts correctly there is not much development on the Prop Pox matter.
Also, it seems that the only thing that is sure is that there are four props by Peg that will corrupt the prop subfile. And that the prop subfiles of poxed cities are corrupted.

But does that mean that all other causes of Prop Pox need to be props also?

Might it be that there are other causes of Prop Pox? Maybe there are other ways of corrupting the prop subfile? Like CTD's caused by very different reasons such as unstable operating systems, inappropriately modded files of different kinds, etc?

The reason why I offer you my corrupted city is not because I think you are bored and like to dig around in someone elses digital crap .... I offered it because I hope it could shed light on the Prop Pox matter. If you think you won't be able to learn something from it, you better spend your time on something difrerent.
But if you think it's useful I gladly send you a yousendit link.

Thanks!

[RippleJet]

But does that mean that all other causes of Prop Pox need to be props also?

Yes, we know for sure that the prop pox is related to the corruption that occurs in the prop subfile, when it becomes more than 16 MB in size. And that file, surprise, surprise, contains only props.
The fact that we know how to identify whether the prop pox has struck in a savegame, is also the reason for wouanagaine's SaveGame Explorer program being 100% correct each time it finds and reports a poxed city.

[FrankU]

Yes, I understand, but I was thinking of a possibility of corruption occurring when the game crashes during saving. I once had such a crash. My city looked OK after a new startup, but who knows?. Or something completely different. Just guessing....

[TiFlo]

All right folks,

I found out last night I've been hit by prop pox. For the second time in the three occasions I've had to develop a large city tile to around 100k inhabitants. Past the urge to throw my computer out of the window, I come here to report and offer my save game if anyone wants to have a look at it.

Here is a screenshot showing I'm not mistaking. I should also mention that the 1st time it happened, I did have the PEG beach original file in my plugins folder and some of its lots plopped. I've since modified the said file following the procedure detailed by bap, and none of it have been plopped in my new region so far anyway.

At that point, I might just obliterate the city and start over. I'll do some cleaning in my plugins, but I don't expect wonders down the road.


Click for full size.

[bap]

I found out last night I've been hit by prop pox. For the second time in the three occasions I've had to develop a large city tile to around 100k inhabitants. Past the urge to throw my computer out of the window, I come here to report and offer my save game if anyone wants to have a look at it.

Here is a screenshot showing I'm not mistaking. I should also mention that the 1st time it happened, I did have the PEG beach original file in my plugins folder and some of its lots plopped. I've since modified the said file following the procedure detailed by bap, and none of it have been plopped in my new region so far anyway.

At that point, I might just obliterate the city and start over. I'll do some cleaning in my plugins, but I don't expect wonders down the road.

Hi TiFlo.
Just to make it clear, did you started this new region -- struck by Prop Pox -- after of before modifying the BDK_resource file? Please remember that those props appear in Maxis low density R$ and R$$ lots even if no BDK lots where plopped in your cities. It would be good to be sure your most recent case of the pox is definitively not related to those props already identified as causing the problem.

If you upload a copy of your infected city to a file server and post the address here, I might find some time to have a close look at it this next weekend. From your picture, I gather that the affected city has about 19.000 disabled props, almost 10 per cent of all props in the city. The larger the number of disabled props, the most spread is the pox. I hope the corruption is not so profound that we might be able to recover the TGI info of the disabled props. These are the ones who lead to the Prop Pox afterall.

Cheers,
Bap

[TiFlo]

Hi bap, thanks for the quick reply.

To address your first concern, This new region was started with the already modified PEG file (I modified the file early this summer, and started the current region about a month ago). Also, as far as maxis R are concerned, I believe I have none of them since I use a maxis blocker for R, CS and I (the BSC one that's compatible with CAM). I'm pretty sure it works, as all the low R I can see are either mattb325's or CP's Early 19th Century.

As for the already big amount of missing props, my mistake was two days ago when working on the South-West corner of the city and having the game run at fast speed several times without going around to check things up. Then yesterday I opened the city, went working on the North-Eastern side of it and discovered the mess....

Link to my savegame file. Let me know if I can do anything else.

Thanks again!

Florian

[bap]

TiFlo, I studied the Prop Poxed version of your city with SC4Savegame. As I was afraid, the degree of corruption of the prop subfile was already so high that no useful information could be extracted from the disabled props. There is no way to discover which prop(s) specifically caused the pox in that city.

Before we proceed, let me introduce a couple of expressions:
1) A "Prop Pox free" city is one for which there is no disabled prop;
2) An "infected" city is one for which there are disabled props (stored at the end of the props subfile);
3) A "Prop Poxed" city is one in which the props subfile has been corrupted. This occurs when the prop subfile contains disabled props and has reached the 16Mby limit size.

As RippleJet already explained, a city becomes infected when lots with problematic props are destroyed or replaced by other lots (for example, when an R$ lot with the problematic beach umbrella in its backyard is upgraded to a R$$ lot). In this case, the program does not delete the offending prop, but stores is at the end of the prop subfile and marks it as 'disabled'. The first attached figure shows a prop pox free city, with no disabled prop. The second figure shows an infected city, with 127 disabled props stored at the end of the file. It is not prop poxed yet (but it will be when the prop subfile reaches the 16Mby limit). In the Prop Record View panel (lower right) one can see that they are marked as disabled (appearanceFlag with no 'visible' flag set) and all have the same IID 0x29000000 (the IID of the beach umbrella prop). Their record size (0x6C) is also different from the usual 0x58 record size of most (non-timed) props.

The third figure shows your prop poxed city. Of the 19515 disabled props in the non-corrupted section of the file, 65 are from T21 (instead of from lots). For all the others the TGI information is deleted. The Prop Record View shows the beginning of the sequence of disabled props. The appearanceFlag has no 'visible' flat set and the IIDs are all set to zero. In fact, the TGI addresses are all zeroed (inside lower right side red box). These deleted props were probably 'healthy' props which became deleted as a consequence of the spreading corruption.

From what was said above, the best chance we have to identify the prop(s) causing the pox in your city would be to recover a backup of that same city not long before is got prop poxed. The offending props should be at the end of the prop subfile, marked as disabled props.

Hope this helps.
Bap

EDIT1: I got another idea. Instead of looking for a backup of the proppoxed city, you could load all other developed cities of your new region into SC4savegame and see if there are disabled props in any of these cities. One might expect that the one approaching the 16Mby prop subfile size would already be infected with disabled props at the end of their respective prop subfile.

EDIT2:

Sorry, but I don't understand.... Do you have any clue what might be wrong or not? Is there anything I can do? Do you want me to send you the second poxed city in that same region?

FrankU, the same idea of the EDIT1 above applies to your case. Maybe the answer to your questions is laying as a group of disabled props at the end of the props subfile in one of the developed (but not yet prop poxed) cities in the same region. If you do have the SC4Savegame tool, I would suggest you scan other large city tiles in that region in search for cities with reported disabled props. If you don't have that program and you do wish to help, you might consider uploading your most developed unpoxed city of that region in a file server, and I may have a look at it.