1. Gimp: a free program similar to photoshop
   
2. scratches mask: you can find this in the gamefiles ...\steamapps\common\TankMechanicSimulator\ModdingTools\TMS Samples\Decals\Decal_Mask_Sample.png (you won't need this if you want clean decals)
   
3. the decal you want to make

The first thing we have to do is make a 512x512 size image.
"but why?" you ask well this is the size the game uses for decals simple as that.


First go to the top left click "File" and then "New..." or press Ctrl+N.


Now set the height and width to 512.
Since we will be working with a mask you don't need to worry about background colour.
But if you have a decal that has white on the edges you want to have it either transparent or a different colour under "Advanced Options"


Now we have our starting point and we can add our decal in the next step.

First open the decal you want to use go to the top left click "File" and then "Open..." or press Ctrl+O.


Go to the bottom right and click on the layer, then hit Ctrl+C.

Go back to our 512x512 image and hit Ctrl+V.
Keep it as a pasted layer for step 3.

Depending on what you use as a decal you will need to up- or downscale it.

To do this use the "scale tool" and click the pasted layer aka your decal.


You will see this window pop-up, make sure the chain icon is closed to stop the image warping.
If you use a decal that isn't square change the biggest value to 512.
If your decal is square pick either width or height.
Press the "Scale" button in the popup after changing the values

Now we see the decal is off centered.


To fix this we will use the Alignment tool.
Select the tool and click on your decal once more.


On the left side we see a bunch of arrows pointing at lines.
Click on the ones outlined in the picture, if you don't see any change click on your decal once more and try again.


Now right click on the pasted layer and click on "Anchor Layer"

Before we make a mask you might wonder what this is and what it does.
To put it simple its a extra image behind the original that tells the program/game which parts of the picture should be displayed and which don't.
It does this by looking at the colours of the mask, with white being 100% opacity, middle grey being 50% opacity and black being 0%.


Right click the background layer and click on "Add Layer Mask..."


This window will popup, select "White (full opacity)" and then click "Add"

This is a optional step if you want a clean new decal skip this.


Right click on the mask and uncheck "Edit Layer Mask".


Now we want to use the wand tool and select the background and things that aren't part of the decal.
You can select multiple areas by holding shift and clicking on each of them.


Now we go to the top left and click on "Select" then "Grow...".
Then in the popup select 1 px and click "OK".
We do this to avoid keeping the white edges from up- or downscaling.

Right click on the mask and check "Edit Layer Mask".


Now we grab the pencil tool (make sure to set the brush size bigger) and try to paint the entire image black, you will see the parts we have selected disappear.

Now that we have a decal with a mask (worn out or not) we can export it to the game.


First off go to the top left under "File" then "Export as..".

Now go to your game folder under: ...\steamapps\common\TankMechanicSimulator\TankMechanicSimulator_Data\StreamingAssets\Textures\Decals and then the map of your choice in my case i will take \Common\
Name it and give it a .tga extension by simply naming it "steam_logo.tga" for example.


This window will popup make sure you have RLE compression turned off or it won't show up properly ingame then click "Export".

Next time you load up the game and go to the paint room you should see your decal.
If i wanted to have this decal with white in the middle i should have used a different colour or transparent background

Thanks for reading, if you have any problems or see any mistakes drop em bellow and ill see to it.