Both district styles and building themes serve the same purpose - to define which buildings are allowed in certain districts of your city or in your city as a whole. They are basically collections of buildings that may grow in residential, commercial, office and/or industrial areas which have this style applied.
Take a look at the two screenshots below:

The left image shows a city district with the custom district style "Berlin Inspired Buildings" from the workshop. This is a district style suitable for for residential, commercial and office areas. The right screenshot shows a district which has the district style from the "European Suburbia DLC" applied, which is a style specifically for low density residential areas. Both will give the district a unique look different from the "vanilla" international style.

Please note that the district style only applies to buildings placed ("grown") by the game. You can still place whatever type of fire station, ambulance, park or unique building within each district as you prefer.

Now, what's the difference between a district style and a building theme?

• District styles exist in the original game without mods. When using the "Building Themes per District" mod, they essentially get replaced by building themes
  
• Building themes are both applied, managed and created with a different user interface than the district style without the mod.
  
• You can only apply one district style to a district, but you can enable multiple building themes for a district using the mod.
  
• For district styles there's a button to publish them to the Steam Workshop with two clicks. Such possibility does not (yet) exist for building themes (but they are XML files which you can share elsewhere).

In order to use district themes your city needs to reach the "Worthy Village" milestone by having 950 inhabitants in your small town.


Once you have reached the milestone the "districts" menu gets enabled in the toolbar. Click on this icon and paint over an area of your city for which you want to apply a certain style.



Afterwards this district automatically shows a label with its name. Click on this label to open the district properties dialog. In this dialog on the bottom right you can change the used district style.

Tip: It is recommended you set this style early on before many buildings appear. If you change the style later all buildings not fitting to the new style will get demolished and be replaced by fitting buildings, which of course start at building level 1 again. So you deprive lots of affected cims of their homes or workplaces for some period of time.

I will explain this for the sake of completeness only, as I do not recommend creating district styles with the built-in UI as it is rather tedious. I really recommend creating a building theme instead as explained later. However if you prefer to stay away from mods this is what you need to do:

Yes, this is the most difficult part. Depending on the type of style you want to create (for residential buildings or for, lets say, office building) you need buildings of several different footprints and for all 5 resp. 3 levels. There are other tutorials which explain how to generate a large variety of buildings from few base building models with different footprints by adding surrounding parking lots, gardens and different props to them.

Tip: Ideally avoid props/assets which require specific DLCs in order to make your district style useful for many other users.

You may also only include buildings of only one level (e.g. Level 1) in which case your style will only be used for buildings of this particular level. For the other levels, default buildings will be used.

Unlike for the building themes discussed later, if you create a district style for, lets say, low density residential buildings, you have to provide a rather complete set as the game will only use buildings from your style (and not from other styles) for this type of zoning and building level, and if it does not find suitable ones, gaps will remain on your zone.
So, concentrate on one type of zoning and level first instead of adding just a handful of models of different levels and zoning type to a style.

Precaution: Before starting to create your own style I strongly recommend unsubscribing from any other styles from the workshop. The reason is that some of them (definitely the mentioned "Berlin Inspired Buildings" style) will confuse the content manager, and surely you don't want to have a buggy style window with all sorts of strange effects. Once you finished your style, you can re-subscribe other styles.

From the main menu, open the "Content manager" and select the "STYLES" section. On its top there is an "Add style" button. Press it to add a new entry to the list and give this entry a name of your choice. Note that the file name will update accordingly.


On Windows you will find the created file in the folder
%LocalAppData%\Colossal Order\Cities_Skylines\Addons\Styles, aka
C:\Users\<username>\AppData\Local\Colossal Order\Cities_Skylines\Addons\Styles

So, now you have a style but for now it is useless, since empty. Time to add content.

Now change to the ASSETS section of the content manager.
Use the search window on the top right to find the buildings to add to your style. For each of them, click on "Add to style ..." and select your newly created style. Afterwards it should show an "Included on 1 styles".

Now repeat this for all buildings required for this style.

As you will notice you can only add buildings from the workshop to your custom style. This is a big limitation which can only be overcome by creating a buiding theme instead, as described in a later section.

Tip: In the STYLES section of the content manager, of you hover over the "i" button on the right you can see for what zone(s) and level(s) you have already included buildings into your style. Unfortunately I am not aware of how to see the level information for every single included building


Now take a city with 950 inhabitants or more, create a new district, apply your style, create the appropriate zoning and watch what happens. Do your buildings pop up? Do you have large gaps in your zone. Do the buildings look too repetitive?

Only if you have done throughout testing, you may then publish your style. For this you change back to the "STYLES" section of the content manager.

Note: If you click on the arrow next to "Subscribe to all" you can see the content of you district style. However, at least for me, this window looks buggy. Most buildings are shown "Missing" although they aren't and I have not yet figured out why some buildings are marked light blue, others not. If anybody knows, please leave a comment.

By clicking on SHARE you will publish the collection to the workshop. No, you can't change the preview image here, but you can (and should) do so later on the corresponding page in the workshop.


There are already too many styles in the workshop which nobody uses because they are undocumented or unusable. So here are some tips to ensure others can enjoy your new district style.:

Tip1: Please only publish styles which satisfy a minimum quality, that is, which contain sufficient different buildings for most building footprints and for all required levels (5 for residential, 3 for commercial/office and gemeric industrial buildings).

Tip2: Create screenshots of your test district and upload them to your style on the corresponding workshop page, so interested users can see how your district looks ... otherwise chances are high they will not even consider suscribing it. Note: Haven't yet figured out how to change the preview image. Drop me a note in case you know.

Tip3: Create a collection containing all the buildings (and their props) needed for your style and link to this from your district style. Otherwise, how are potential users supposed to know to what buildings and props they have to subscribe to see all the glory?

Tip4: In the description of your district style, add a note about required DLCs. If, lets say, you included several buildings which require the "Art Deco DLC" then document that this DLC is required for the style (as it is required for the buildings used by this style).

Tip 5: Clean up any test style zombies you shared just to check how sharing works.

As we have seen in the previous chapter, creating a custom district style is simple, but creating a useful district style is a lot of work. To circumvent these limitations, the "Building Themes per District" mod uses a slightly different concept, thereby replacing district styles.

Attention: As usual, read the mod description about incompatibilities, side effects, frequently asked questions and for more information how to use it! Some mods will not allow to load a second game once returning to the main menu from the first loaded game. This mod is well-behaved in this respect.

After subscibing to this mod and enabling it in the content manger's MODS section, the content manager will still show the installed district styles, however you will have no longer a need to manage them there.

The first steps of using building themes are usually identical to the ones described in the chapter for district styles - make your city grow above 950 inhabitants, then use the "district" menu to draw a district.

But wait ... in the mod options you can enable building themes to be available right from the start, so you can give your little village (as a whole) a certain look even before districts allow you to do so separately for each district. For this enable "Unlock policies panel from Start".


The next difference becomes obvious when you open the district properties dialog - there is no more dropdown list for the district style.


Instead you are forwarded to the policies dialog (which is available for both the city as a whole and for each separate district) where you find a new tab on the top right, labeled "Themes". Clicking it will reveal a list of available themes.

Where does this list come from? Well, its essentially a copy of all the district styles which existed previously, so if you created a custom district style it will show up here besides those district styles that came from the base game or DLCs such as European Suburbia.

Warning: I want to mention already at this point that while the Theme Manager will pick up any district styles and convert them to building themes on the fly, the same is not the case the other way round. Any changes you do while this mod is enabled will not alter the district styles which existed previously. Yes, this can be a bit confusing.

Tip: In order to avoid having to specify the look of each district of a larger city after enabling this mod I recommend that you use the mod with a new or small city instead of "converting" an existing large city to use building themes.

After you have checked the option "Enable Theme Management for this district" the list becomes active and you can choose the themes of your choice. In contrast to the district styles you can apply as many building themes as you like to you city or district. This has quite a few advantages:

• It allows you to have a district with a mixture of residential buildings from, lets say the "European" and the "European Suburbia" style and maybe even the default "International" style.
  
• It allows you to apply a theme for residential buildings and another one containing specific office buildings and third one containing only commercial buildings, so different zones within the district will each have a customized look. For example you might choos "European Suburbia" (containing low density residential buildings) and "Berlin Inspired Buildings" (containing high density residential buildings) at the same time.
  
• Most of all ... it allows you to create a building theme with just a few selected buildings which would not work as a standalone district theme because it does not cover all required building footprints, let alone all building levels.

By unchecking "Allow buildings which are not in any theme" you can further tweak the behaviour. For example you can avoid the two Art Deco high density residential buildings from the "Art Deco DLC" to appear in the middle of a block of European buildings where they do out of place imho.

Now lets create our own theme. As an exmple I created a distinct building theme for residential Art Deco buildings I got from the "Art Deco DLC" and from the workshop. They are not enough to form a district style on their own, but for a building theme this is not necessary.

From the policies tab you can access the "Theme Manager" via the button on the bottom. The following window will pop up:


See also the section "How To Add Custom Themes And Modify The Built In Themes: Theme Manager" of the mod's workshop page for help on the usage and background information. I won't copy everything here!

On the left hand side you find alost of all building themes. The "European" and "International" are provided by default, furthermore thems have been created "on the fly" for all existing district styles such as my sample "Art Deco District Style" from previous chapters, as you can see in the screenshot.

Warning: Again, that you see your district styles in this window does not mean you can edit them here. What you see is a kind of copy, so your changes here are saved separately, they do not modify the .crp files which you created by the content manager!

In the center list you see all available buildings together with their zoning, Level (L1-L5) and building footprint. And I mean all buildings, both buildings from the default games and DLCs as well as buildings you subscribed to in the workship. (Unique buildings, with or without RICO settings will not applear though, only buildings for specific zones.) You can filter this list with the option from the toolbars above and below the list:

• You can filter it by zone. So if you are only interested in low density residential buildings for your style, disable the rest (button "None") and then just enable the leftmost green icon.
  
• You can filter for default (built-in/DLC) or custom (workshop) buildings only
  
• You can further filter for included or excluded buildings
  
• You can filter for buildings of a certain level or footprint only, just in case you need a bit more variety for a certain footprint.
  
• You can filter for a keyword, e.g. "Art Deco"

Now, compare this comfort to the incomplete, yet hardly concise list in the content manager!

By hovering over or clicking an entry in the center list a preview and details are shown on the right side. The view on the top can be rotated with the left mouse button. The "Spawn rate" will determine how often this building is used relative to other buildings of the same level and footprint.

The "Upgrade" text field allows to specify the name of another model to which this building shall upgrade. Typically if you have all levels for one building you will want "Building A L1" to upgrade to "Building A L2" and that one to "Building A L3" and so on. If you don't have a version for the next level of a building or don't care, just leave the field empty. Note that you don't have to type the whole name. Once you start typing a list with fitting suggestions comes up to choose from.

Last but not least a button allows you to place the specific building on a suitable spot of the map - a nice way to see how it will look when built. (You will have to let the game run so the building actually gets erected. And make sure the theme policies allow the building at this place or it will quickly disappear.)

All changes you do are saved instantly, so be careful when modifying themes you have currently in use.

For our example, all we have to do is:

1. Ensure all the buildings we want to include are subscribed and availabe (If they require a DLC we don't have they don't appear in this dialog.)
   
2. Create a new building the, for example "Art Deco"
   
3. Limit the list to low residential buildings, since this is what the theme should contain.
   
4. Browse the list or filter by name in order to find the wanted buildings.
   
5. Check each of them (or use the "All" function if only wanted buildings are visible)
   
6. (Optional) Customize their upgrading behaviour. For the few Art Deco buildings in the list this does not much sense.
   
7. Enable the new building theme together with another one which delivers buildings for all the other zoning types (e.g. International or European) for either the cuty or a certain district.

By enabling a second building theme next to the created one we can ensure there's plenty of buildings to choose from for every level and footprint. However, we will find that residential buildings from the other theme are also used, even if our own theme contains enough buildings for a certain level. If this is an issue for you, you will need an alternative approach:

In this case you should explicitly include buildings of all zones (or at least all zones for which you intend to use it) into your building theme and make it the only theme allowed in the district.

When you have the building style configured to your liking you will wonder how to publish/share it.
Unfortunately there is not yet a possibility to share a building theme via the workshop. As I noted earlier there's no point in trying to share the district style it might be based on since this file did not get updated.

Unlike the district themes the building styles are stored in XML files at the following location:
{Steam folder}\steamapps\common\Cities_Skylines\BuildingThemes.xml
So you can copy them and share them with your friends ... but not yet through the Steam workshop.