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The Prop Pox!

Started by snorrelli, May 03, 2007, 08:53:49 PM

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BarbyW

From the extensive testing done by BSC and also during the development of the SC4Explorer program, we came to the conclusion that Prop Pox is triggered when a Maxis prop with a NightTimeState is changed to have a Prop Time of Day property. This prop is usually one commonly used on Maxis lots especially the residentials.
There is a lot more information in the other Prop Pox thread with the research done by bap.
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FrankU

So does that mean that all non-Maxis props are clean? And so it is safe to use all prop packs that contain new material?
Maybe you guess why I ask:
1. I'd like to help finding an unfound cause.
2. I'd like to start a new region without Prop Pox Viruses in the plugins.

cogeo

Quote from: BarbyW on October 14, 2010, 03:34:17 AM
From the extensive testing done by BSC and also during the development of the SC4Explorer program, we came to the conclusion that Prop Pox is triggered when a Maxis prop with a NightTimeState is changed to have a Prop Time of Day property. This prop is usually one commonly used on Maxis lots especially the residentials.

And more generally, any change that causes a prop-reference record of different length to be saved in the gamefile (city). Timed props store additional information in the gamefile, like state or days elapsed since activation, making the prop-reference record larger. I'm not sure, but I think that props using the NightTimeState property are just like the simple ones, as they don't need to store anything additional in the gamefile (the prop just shows a different model during the night, so such props might not be really "timed").


Quote from: FrankU on October 14, 2010, 03:41:02 AM
So does that mean that all non-Maxis props are clean? And so it is safe to use all prop packs that contain new material?

Neither the Maxis props are problematic, nor the non-Maxis ones are necessarily OK. The problem basically occurs if you save a city containing references (instances) of the prop, and then install a modded version of the prop, and more specifically a mod that causes the prop-reference record length to be saved in the gamefile, for example changing a prop from simple to timed or vice versa.


Quote from: FrankU on October 14, 2010, 03:41:02 AM
2. I'd like to start a new region without Prop Pox Viruses in the plugins.

The Prop Pox is not literally a "virus", instead it's a data corruption problem caused by the combination described above.

In theory at least, the prop-pox won't occur as long as you do not install a modified version of a prop, to which the city file does contain references (instances of the prop). Ie if you start a new region, even with PEG's mods installed, you should not get the prop-pox if you don't unsinstall them (causing them to revert to their original version), or install another modified version.


Quote from: FrankU on October 14, 2010, 03:41:02 AM
1. I'd like to help finding an unfound cause.

This could be an extension (new function) to the SC4Explorer program: it should load the city files one by one, and for every prop instance found, check if there is a discrepancy (different record length) between the prop reference in the gamefile and the prop definition in the effective (last loaded) plugin. I dnn't know if this is technically feasible or how much work it really is, it's just an idea. I would say don't delete your problematic region, instead backup it, along with your currennt plugins installion, of course. It could prove a good testbed.

FrankU

Quote from: cogeo on October 14, 2010, 10:21:54 AM
The Prop Pox is not literally a "virus", instead it's a data corruption problem caused by the combination described above.

Ah, no now I remember; the Pox is caused by bacteria, so it should be called an infection.
And to make everything clear: it is completely clear to me that the Prop Pox has nothing to do with computerviruses. I just said virus, because, well, the Prop Pox is referred to as if it were a disease.

kodlovag

I have several questions

I'm working on a realistic nightlight mod based on Light Replacement Mod v3 by mrtnrln. See thread http://sc4devotion.com/forums/index.php?topic=12101.0

During thinking on how to insert light poles and cones into stoplights I found it probably will cause prop pox. It would require changing the stoplight prop from ResKeyType1 to 4, which means different prop length. If I understand well, that can cause prop pox. Can somebody confirm it?

Furthermore. I read through this thread and what I understand about prop pox, any change in the prop length can cause prop pox. This means, that the LRM v3 already can cause prop pox, because it directly replaces maxis streetlights with new models, and the new props many time have different amount of data in ResKeyType4 line.
Am I right, that any replacement type mod is a potential source of prop pox? What should I do, if I know, that my mod will inherit prop pox from LRM v3?
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