Creating the first mutator

Simple step-by-step instructions for creating the simplest mutator.

1. First of all, create a subfolder in the kf folder with the name of your future mutator, and in it a Classes folder. For example, you might end up with the following structure:

C:\Games\KF\NewMut\Classes

2. Next, in the Classes folder, create a file with a .uc extension, for example Mut1.uc

3. Open the killingfloor.ini file in Notepad in the System subfolder of the game folder. Find the line [Editor.EditorEngine] and add the line after it:

EditPackages=ИмяПапкиСВашимМутатором

that is, in our case:

EditPackages=NewMut

4. Open the file created in step 2 in Notepad and paste the code snippet there:

class Mut1 extends Mutator;
defaultproperties
{
GroupName="KFNewMut"
FriendlyName="Новый мутатор"
Description="Простой мутатор"
}

Please note that the word class must be followed by the same name as the file created in step 2. Also, the name assigned to the GroupName property must always begin with the letters KF. Save the file.

5. Compile the mutator. To do this, create a file with a .bat extension in the System subfolder of the game folder. for example make.bat and using notepad paste the text there:

del NewMut.u
ucc make
del steam_appid.txt

Explanations of the code. The first line is to delete our compiled mutator, if it already exists, since if this is not done, then when changes are made to the mutator code after the first compilation, they will not take effect. With the second line we force the ucc utility (the ucc.exe file should be in the System subfolder of the installed game) to compile all killing floor mutators, including ours. The third line we delete the file created by ucc after compilation, which prevents the game from starting.

6. Save and run the file created in step 5. You should now have two files in the System subfolder of the game folder:

NewMut.u
NewMut.ucl

This is the mutator itself and its description file.

That’s all. You can start the game, create a new one and see your new mutator in the mutators tab. Our mutator does not perform any functions, it is just a shell.

Having studied the unreal script, you can write a functional mutator. You can start studying from here