Decals are 2D textures that are projected onto a 3D model to add details that don't require their own geometry, such as stickers, painted signs, posters, buttons, panels and much more! This add-on provides a quick and simple way to add a decal to your model, without the complexities or price tag of existing solutions.

Add Decal: Select a model in your scene and press Add Decal, then select an image from your computer to use as the decal. A 2D plane will be created in your scene which you can use to position, rotate and scale the decal that's projected onto the model.

Delete Selected Decal: With a decal plane selected, this will delete the decal, removing the necessary nodes from the models shader graph. Deleting the plane manually won't clean-up the material, leaving the decal behind!

Clear Decals: Let's say you've plastered decals all over a model, getting rid of them one at a time is a bit tedious, so this button will remove all decals associated with the models you have selected.

When adding decals to your model, a special decal node is added to the shader graph of your model. Not only does this allow the decals to be added to your models in a non-destructive manner, but it also allows you to customize the decal!

Shader: These input/output sockets are how you chain the decal together in your shader. The decals should generally sit at the end of the chain, with your material shader as the input, and using the output for the material surface.
Scale: While it's generally better to scale the decal using the decal plane in 3D space, sometimes you need to make small adjustments and this can be easier.
Weather: Provide a texture mask to apply weathering to the decal (see below).
Weather Factor: Control how much of the weather mask is applied to the decal.
Emission: Maybe your decal needs to glow? This controls the emissive strength of the decal.
Normal: Provide a normal map for the decal (see below).
Metallic/Roughness/Alphas: Allows fine-tuning the metallic, roughness and alpha of the decal.

The decal node is a shader group, so if you need further fine-tuning of the parameters, feel free to open the group (tab by default) and get tinkering!

Adding a weathering effect (also known as damage) to a decal is one of the easiest ways to elevate the realism of your decals and make them look like part of the surface they're projected onto. While the add-on does not provide you with weather noise/masks out of the box, it makes it easy to plug your own in. Since there's a million ways to create weathering, from simple noise nodes to full-scale scratch maps, it didn't make sense to include them directly. Bring your own noise!

Normally (pun intended), a decal is projected flat onto the surface. For surfaces that are less-than-flat, or decals that need to follow the displacement of whatever it's projected onto, that's where you can provide a normal map! This works especially well for painted decals or bumpy surfaces.

Frequently Asked Questions:

Q: Does it come with decals?
A: No, you'll need to source/create your own decal images, this add-on provides the projection utility. There's a million and one ways to use decals, so bloating the add-on with graphics most people won't use seemed like a bad idea.

Q: Why is my decal projected weirdly?
A: Ensure the rotation of your plane matches the surface you're projecting onto.

Q: Why does my material turn pink when adding a lot of decals?
A: Blender appears to have a limit (around 15) on how many shaders can be chained together before it simply refuses to render the material. Split your model into more materials if you need to apply more decals!

Q: Why doesn't it support depth/parallax?
A: To keep things simple! There are much more advanced decal add-ons available, however SimpleDecal aims to keep things simple (and cheap!)

Q: Why do I need to provide my own weather masks?
A: There's a million and one ways to apply weathering, bloating the add-on with noise masks most people won't use seemed like a bad idea. Everyone has their own preference on noise/damage maps to fit the style of the decal/surface/project.