Using the decal tool

The Decal Tool requires Blender v4.0+

User’s Guide Video
Procedural Non-Destructive & real time Decal Placing Tool

Basic Use

The first step is to press the Decals button on Sanctus Library Panel

Navigate through the categories and press the thumbnail image to change the selected decal
Once you select the decal you want to add you can press one of the following buttons: Add Decal, Add Custom, Swap Image

Add Decal

Once you press the button you will see a green aiming guide that will let you select the object and face to position the decal, left click to confirm.
You will see all the parameters for the decal on Blender’s modifiers tab.

Moving/adjusting The Decal after placing it:

The best way to do it is to fist uncheck the Apply and make sure Guide is checked on the modifier. This was you will be able to see if the Projecting Distance is enough and the position and rotation of the decal is correct and as you want it, adjusting the Projecting Distance will be needed in general depending on how and where you move your decal.
For the best result the guide box should completely intersect with the area where the decal will be placed.
Once you move it to the place you want check the apply checkbox and it will be ready.

You can also use the new Reposition Decal button

Tool Parameters

Scale: Decal Scale
Rotation: Decal Rotation on local Z axis
Offset: Increase and decrease distance from the decal to the target object (negative values allowed)
Guide: When Apply is unchecked this shows the limits of the projecting distance
Apply: Uncheck to verify if the target objects surface is completely intersecting with the projecting distance box. Also requires less processing to move when unchecked.
Remove Backface: In situations where the projection hits 2 overlapping faces (https://youtu.be/8xzd8LTlCmQ?t=437) you will see a 2nd mirrored decal on the back of the object, this option will remove it.
Projecting Distance: The maximum distance the decal will look for on the target object to generate the decal
Target Object: the object where you placed the decal (do not change it manually)
Material: the material used by the decal (do not change it manually)
Replace Color: Replaces the decal with a solid color respecting the alpha.
Color: The Color used to replace
Emission: Increases the emission of the decal
Metallic: Switch decal metallic / non metallic
Roughness: Controls decal roughness
Roughness Grime: Adds variation to the roughness

Directional Damage – Damage tearing the decal along a specific direction
Texture Scale: Texture Scale
Rotation: Texture Rotation
Amount: Amount of damage

Border Damage – Adds damage from the borders of the decal
Texture Scale: Texture Scale
Amount: Amount of damage
Cracks: Adds cracks to the border of the damage

Holes Damage adds damage in the form of holes
Texture Scale: Texture Scale
Amount: Amount of damage

Tearing: Adds a border to the damage simulating tearing paper decals or other materials
Tearing Color: Change the tearing border color

Global Damage Affects all the damage
Damage Seed: Gives different results using the same parameters
Damage Overall Scale: Scales all damage

Discoloration: Adds some color variations like stains

Bump
Wrinkles: Adds wrinkles to the decal, like if it was badly placed or
Texture: Adds some texture to the decal (a bit like crumpled)
Bump Multiplier: Bump Multiplier