Ah yes, my second question in one day. I found instructions on how to change the lighting data for worlds that already use custom lighting, but I want to edit those worlds that use the default "Sunset Valley" base game lighting to a custom one. Currently I am using a lighting mod by dDefinder, but this doesn't play well when I travel to worlds that have different lighting: it interferes with the custom light and I get weird crash-like situations, i.e. the screen turns occasionally one solid colour and I have to use the task manager to exit the game.
So my line of thinking, and it may be totally wrong is, that to solve that I should simply edit the homeworld to custom lights like that of the mod and get rid of the override. Can I do this with S3PE alone?

The worlds I want to change are Sunset Valley, Riverview, Barnacle Bay, Hidden Springs and some old custom worlds that still use the default light. My idea is to change Sunset Valley to the mod light, Riverview to that of Appaloosa Plains and Hidden Springs to that of Moonlight Falls or Twinbrook. The custom worlds and Barnacle Bay I haven't decided yet.

Don: I do that with all my worlds and yes, you should only need S3PE for it. Just a matter of importing, overwriting and saving. I have never used an override that would apply to all worlds. Of course, you already know to keep a backup of the original world. There are only a few worlds that I had to do additional work like editing the file that changes water murkiness.

Good. So I can start experimenting now.

I hope it's okay to necro my own thread.
After a long time I was finally able to try my hands a bit at this. My test world is Hidden Springs from the Store.
I imported the _INI and _IMG files from St. Claire and so far everything is working fine, except for one thing: the St. Claire water is conflicting with the water at the map edges. I guess that one is part of the distant terrain and as such cannot be changed.
I tried the same then with the Jericho sample files from @simsample and there the difference is really obvious.

So let's say I want to keep all settings except for the water colour and want to revert that to the Sunset Valley one, where do I have to make the changes and how?

@Don Babilon If you are importing colour ramps, then the water colour is contained in those ramps.

There should be five colour ramp (IMG) files, one for each 'weather' type.

Each colour ramp looks like this:

The strips of colour each represent one aspect of lighting, for example sky colour, outdoor shadow colour, water colour.
The strips change according to the time of day- the figures 0 to 24 along the bottom show this. You can see that there are more orange colours at sunset and sunrise (6am and 6pm-ish).

This is a template showing what some of the colours in the image represent. You can see that there is one labelled for water colour- you can see that for this ramp it is very dark grey-blue, almost black.


What you would have to do is to change that strip of colour in each of the five ramps to more closely match the distant terrain. How I would do that is to zoom in on the image in a photo editor, and select that strip and change the tone, contrast etc, until I got a match. Or else, copy that strip from the original world colour ramps and paste it over. (ETA- that's assuming that Hidden Springs has colour ramps- if it uses the basegame colours then this is not possible.)

Remember though that the colour ramps need to be in a 32bit DDS format, so you need to use a program that can support this.

Okay, that is something I cannot do, due to the lack of any suitable picture editing programme.

I'll have to try a different approach without any use of any colour ramps then. I suppose it's possible to change the light in a custom world without any ramps and just _ini editing? What I am trying to do mainly is change the, bluish, night light in any custom world that still uses the EA default. That can be done without colour ramps, right? But while I could find some info in dDefinder's _INI-based mod, I couldn't find anything in the _INI files that I extracted from custom worlds or in the Jericho test files you provided in the CAW thread.

The EP colour ramps tie up with the EP ini files- they go together. This is quite different from the basegame lighting, which is purely defined by RGB values in the ini files.

You can find the basegame ini files here:
[Game Install Location]\Electronic Arts\The Sims 3\GameData\Shared\NonPackaged\Ini



As you can see, there are files for the five different 'weather' types (called here clear, custom, overcast, partly cloudy, stormy). The other files (sky common, sea) determine factors like sun size and wave action. In the base game, you will hardly ever see anything but the 'clear' sky parameters, so this is the main one you need to edit.

If you look at the 'Sky_ClearSea.ini' file, you'll see that this gives the colours for the sea when the clear weather is active. So that you don't need to touch.

If you look at 'Sky_ClearLight.ini' you'll see the light parameters for the clear weather. This looks more likely to be what you need; there are parameters laid out like this:

And so on. The time of day refers to hours; so 4 is 4am. There are also parameters for ambient colour at night, and fogginess.

The other ini files for clear mostly contain cloud and horizon parameters, but there might be something in there which you wish to tweak.

What I would do is to backup the original ini files, and then edit the RGB colours for the night lighting and time of day colours, to get the light you want. You just need to clear caches and run the game in Sunset Valley to test. I'd start by just reducing the blue values, to see what it looks like.

I think editing these ini files is a little more tricky than editing the DDS files, as it's non visual.

If you did want to try image editing, you could always try GIMP- it is free and there are DDS plugins for it.
https://www.gimp.org/
https://code.google.com/archive/p/gimp-dds/

Ok, thanks for this, but one, perhaps, last question: Can I import changed base game ini files into a custom world, too, or are these only viable as a default replacement for all worlds that use the base game settings? All the custom worlds I checked so far do this with the 5-6 inis and the _IMG colour ramps like those for Jericho, while dDefinder's mod is a default replacement for those inis you listed just now. Can I simply import dDefinder's into, let's say Sunset Valley, and have it then apply to Sunset Valley only?

I've never tried that- let us know what happens!

It seems to work. I just closed my test game. While looking for lighting mods that kept EA base water (quite rare it seems) I found this here on MTS: http://www.modthesims.info/download.php?t=484971 and it's completely _ini based. I imported it into a fresh copy of Hidden Springs and at least the night colour has changed. Hard to say though whether all parameters have been applied.
I also looked in my worlds folder to see whether I had a custom world that did use custom lights with only _ini files and no colour ramps and I think I found Riverblossom Hills by kiwi_tea to be such a world. The only thing that puzzled me inside there was that one of the _ini files mentioned the lunar cycle. Riverblossom Hills is old and has never been updated for Supernatural. Did we have a lunar cycle before SN?

I've been playing the test Hidden Springs for two Sim days now and haven't encountered any issues yet. But maybe I should have taken a more extreme lighting mod to see what worked and what didn't. But, well, try to find a mod that says whether it uses colour ramps or not.
I will have to see whether this approach also leads to those weird crashes I had when using a default replacement (see post #1) and how or if travelling is affected (my guess is that it won't).

Ok, so I have been looking a bit more closely at the ini files in Riverblossom Hills. The first observation is that it contains only the respective inis for Stormy (Sea, Sky, Light). The RGB values for these are, as far as I can see, always balanced (like 50, 50, 50) but the nights in-game have the blue hue from the base game. Does this mean that there is something else that overrides these or does the game simply not use the Stormy parameters?