Hello Everyone

I'm not a professional modder or asset creator, so maybe this isn't perfect, but it's working for me. Also my native language is not english.

1 ► you need a photoshop like program, such as gimp

2 ► you need a template, a .fbx file

Download this file

https://drive.google.com/file/d/1Ou4nmZeW_inAzk4SlozCAP1xWMmYure_/view?usp=sharing

3 ► it's important to respect size & format or the game won't respect your custom asset.

4 ► Find the graffiti you want in your town and isolate it from its original background

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5 ► Now you need to apply the standards the game need to understand your creation. Many creators are not understood, by people but also by the machines.

6 ► Use corrects and acceptables resolutions

When exporting your graffitis you can only use these resolutions

For a 1:1 ratio

width x height

16x16
32x32
64x64
128x128
256x256
512x512
1024x1024
2048x2048

For a 2:1 ratio

16x32
32x64
64x128
128x256
256x512
512x1024
1024x2048

If you don't follow theses requirements, the game will punish you by making a very weird asset, you don't want. Believe me.
You should also know that the bigger is your file, the heavier it will be in the game. For example a 512x256 file weights around 0.6 MB.

7 ► GREY BACKGROUND
You want a grey background, the game understand the grey as transparency, so maybe there is 50 shades of grey in some erotic and ♥♥♥♥♥♥ movies (and in the game), but I'm sure the grey I use in the image below is working. Look in the colour window the parameters.

[servimg.com]
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The game overcolour and oversaturate, so maybe you'll need to rebalance. For my part I just desaturate by -25. It's ok. Not perfect, but it's ok.

[servimg.com]

Name it like yourgraffiti_d.png or whatever_d.png

8 ► WHERE TO EXPORT THAT ?

Well my friend, this is the path :

C:\Users\Username\AppData\Local\Colossal Order\Cities_Skylines\Addons\Import

[servimg.com]

You need that underscore sign and a .png format. PNG understand that when there is nothing, there is nothing ! JPEG translate nothing in white and you don't want a white square around your graffiti, right ?

9 ► ALPHA STUFF
I think it's also for transparency, shadows, I never really understood, but you can consult some other guides, GC VOS explain that very well, but I'm dumb.

For the game to understand your art, you need to create an evil twin to your graffiti, or alpha. Without an alpha evil twin de los cojones, the game will say to you, like Syrio Forel : Not Today...

To get that, you need a black background (you turn your grey BG in a black one), and you fill your graffiti by a special colour. Don't ask me why I use this colour, I just use the one some excellent and nice asset creators gave me to help me when I ask them (Sparks and Feinbild)

[servimg.com]
[servimg.com]


And to export it, use the same resolution than the "original", the same folder

C:\Users\Username\AppData\Local\Colossal Order\Cities_Skylines\Addons\Import

and name it like this

samenamethantheotherfile_a.png (a is for alpha I guess)

[servimg.com]

Before going into the game to upload your graffiti, don't forget to get the .FBX file in the same folder. Must be named like the evil twins file, the graffiti_d.png and the graffiti_a.png and should be graffiti.FBX. See it as a parent and the two children.

10 ► UPLOAD

Now we can upload.
If you have a lot of mods installed, it could be long.

Just do as the images

[servimg.com]

[servimg.com]

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[servimg.com]

[servimg.com]

[servimg.com]

[servimg.com]

[servimg.com]

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Hope it had been useful for you and that you paint that walls in your cities.

Tip: To get light files, I export my .png in a 256x512 resolution and I resize it with Procedural objects. I use this only format to be fast, I know, I'm evil.