In the mean time this can be of help: https://forums.bistudio.com/topic/191167-what-can-we-do-with-arma-2-maps-now/#entry3032652

Maybe an Alternative, but sadly not a real solution for it :/

Unfortunately that doesnt help us and many others out.

We have a highly customised lighting config pre 1.60.

Now we're going to have to rebuild the entire config from scratch, again. With an TrueskyAPI supplied for Arma3 this would take much much less time to rebuild & re-implement.

Plus having fully documented samples for terrains would be a bonus, which would save us from having to pull a mash of data from default configs and other sources just to piece together how everything works with the new shaders. As well as assist new terrain authors with stuff they don't understand.

Yeah the lack of proper documentation is a bummer but you probably won't need to rebuild the whole config.

There are two main things that cause issues with maps post-Visual Update.

Different simulWeather settings and the need for the fog to have an alpha channel.

Unless you had custom cloud settings as well all you have to do is delete class simulWeather from your cfgWorlds config. This should use new, correctly working cloud config. Alternatively you can look for config.cpp in map_stratis.pbo and for class simulWeather there to see all the values, then just copy this class into your map and tweak it as you see fit.

Now when it comes to lighting itself it's tougher. You will have to go into your class lightingNew and under each lighting subclass you will find something like fogColor[] = {r,g,b};
Because it has no alpha you get black fog with new lighting. What you have to do is to add a proper alpha value to every fogColor variable in each lighting subclass like fogColor[] = {{r,g,b},a}; Yeah it's a lot of work but new lighting is totally worth it.

Alternatively you can just go with the default Stratis values by using its lighting0 through lighting44 classes - may be they will work great for your own map? BIS values are pretty realistic and fit tropical and desert terrains really well.
Deleting whole lightingNew class should work too - it should use new visual update values by default as well - making your config smaller.

IF however you want to have pre-visual update lighting back this is doable too!
But ONLY if your custom config contains fully defined lightingNew class

You will still need to copy new simulWeather values and then all you have to do is set skyColorInfluencesFogColor to 1 and under HDRNewPars put these values: https://configs.arma3.ru/154.133741-ffaa/configfile/CfgWorlds/DefaultWorld/HDRNewPars.html

tonemapMethod being the key parameter. 1 is the new tonemapping used in the visual update. 2 brings back pre 1.60 tonemapping that will let you have your old lighting look right.

Already stated ours is completely custom config, i.e. everything IS custom.

Inheriting from anything other than CAWorld is lazy and careless. Inheriting any other terrains config puts your own terrain at risk from any changes in those that you haven't over-written within your own config.

I have a rebuilt version of our config using the new DefaultWorld & CAWorld config's as working examples.
And as mentioned we're now having to go through every single entry and rebuild the entire enviroment/lighting parts of the config from the ground up.

This is a major setback with our terrain. IF we can't fix this, then do we seriously continue after putting years of development time into it??!!

I can see why the Taunus guys have quit developing thier terrain after this "update", others will no doubt follow at a rapid pace unless something is done by BI to alleviate these issues.