Backward compatibility over multiple versions of a mod

Post » Sun Mar 15, 2015 2:43 am

Scenario: you are responsible for maintaining a mod where the player progresses over time. The mod has its own worldspace (or changes the vanilla landscape), has quests, and the works.

Three questions about releasing new versions:

  • What do you have to do/provide/worry about from the beginning in order to be able to release new versions of the mod without the player losing his accumulated progress?
  • What you can, and cannot, do while developing a new version (keeping the same ESP name)?
  • What may force you to change the ESP name (say, from “MyMod v1.esp” to “MyMod v2.esp”)? And what you gain and lose by doing that?

As some of you may guess, my concern is my VOX POPULI mod. It seems that I can see a light at the end of the tunnel and may be able to release the mod soon (this year, I mean).

Problem is that I am full of ideas for new features and will have to decide whether to implement them before the fist release, or release a basic, limited version of the mod and add these feature, one by one, in future versions.

I can figure what I will have to do with the particulars of my mod. My questions are about more generic precautions and actions.

For example, the southern part of my island is sort of unused at the moment. I have a vague idea about adding a village or two in the future and may have to edit the landscape, like extending a shoreline, removing a mountain, create a road, edit pathgrids, etc. Will it be safe to edit the landscape? Or I’d better improve on the idea and do it before the first release?

Things like that.

I would appreciate any advice you may give.

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Chris Guerin
 
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Post » Sun Mar 15, 2015 4:04 am

I know with SDR that I caused a lot of headaches and confusioN for people by changing the names of different portions of the mod. In some cases it was necessary, in others probably not. Especially when it came to load order and Boss. But I think in many ways the changes were justified and inevitable. It was a complicated mod and evolved quite a bit over time. Also, since it was primarily all scripting, replacing one set of files with another didn't start becoming a problem until later in it's evolution when I started adding spells and potions that a player could use. Then I had to come up with systems that allowed for updating / upgrading without forcing folks to do a complete uninstall/save/new install. And for those that did have to do that, I created a system that would allow for them to restore any lost spells in the process.

Changing variable names and form IDs can wreck havoc between versions. With SDR I can get away with it more because whenever there is a new version, it detects it and automatically refreshes everyone's stats/actor values.

However, with a quest mod, I imagine you would run into serious complications if someone is in the middle of a quest. If you change the filename, you would for sure wipe out all previous progress because the save game data is tied to the file name. So I would only change the file name if you wanted to force people to start from scratch.

Changing variable names could also cause problems, particularly with quest variables and token variables. Custom functions you won't have to worry about.

Changing form IDs would cause issues too, so I'd be careful with duplicating an item and deleting the original if the original was in use. Changing editor ID's or the properties of things isn't that big of a deal.

Removing things could be an issue if it's quest related or the user can possess/use it.

Adding things shouldn't be a problem.
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lisa nuttall
 
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