That's a first, AFAIK. Is that mod available to download or subscribe to?
I'd greatly appreciate it if you could inform us of how it's done please.
Well, the mod is only part-way done, so I haven't put it anywhere yet.
The basic thing you need to understand is that essentially Landmarks.artdef seems to handle everything that appears on the map as a 3D model (in terms of districts/improvements/buildings). Here's how I created an improvement:
1) When you create a new Landmarks.artdef, you'll notice there's an entry called "Landmarks". You'll want to create an entry here, I named mine LM_VILLAGE, but I don't think the name is important, this is just following the formatting used for other Improvements. You can set it to randomly rotate here if you wish.
2) Under your new header (LM_VILLAGE in my case), there's a section called Eras. This is where you define what art asset you want to use. Here's how I have mine set up:
You just need one entry with Tag_Era/Tag_Culture set to default and Tag_Appeal set to ANY for it to work, and the name you choose doesn't matter. Asset will let you choose which asset you want to use for the improvement. Make sure to Save this before continuing. You can play around with this stuff when you're confident, I found it pretty self-explanatory.
3) Once that's all set up, you'll want to set up an Improvements.artdef. Add an entry under Improvements, and it's important that the name of this element is the same as the name of the improvement as it appears in your mod files under <Types>. Set up StrategicView as Firebug explained for buildings, it's pretty much the same thing, and then under Landmarks, you'll want to add a new entry. Under Xref, you'll be able to choose what asset you want to use--you can use any default improvement, but if you've set up a new one under Landmarks.artdef like I just explained in the first two steps and saved the file, it should appear here and you should be able to use it (this is how I used district assets for my improvement).
4) Don't forget to include this stuff in Mod.Art.xml (afaik you need to do this manually). Districts.artdef, Buildings.artdef, and Landmarks.artdef seem to need to go in the Landmarks element, and Improvements.artdef has its own section. I'm not 100% on how this is done, but this has worked for me:
You should probably be able to figure out Districts from this too! Just remember, BaseVariants sets the "base" that the buildings sit on, you'll want to create one for each arrangement of buildings.
