Using The Decal Tool (Blender v3.5+)

The Decal Tool requires Blender v3.5+

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

Add Custom

This option works exactly as Add Decal but instead of adding the selected image it browses through local folders to use a custom image instead.

Swap Image

Select an already placed decal and click Swap Image to replace it with the one selected in the preview.

Tool Parameters

Scale: Decal Scale
Rotation: Decal Rotation on local Z axis
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.
Emission: Increases the emission of the decal
Metallic: Switch decal metallic / non metallic
Roughness: Controls decal roughness
Damage: Adds procedural damage
Damage Texture Scale:
Damage Seed: Controls Damage Seed
Tearing: Adds a border to the damage simulating tearing paper decals or other materials
Tearing Color: Change the tearing border color
Decoloration: Adds some color variations like stains