LW>>B?: decals, Surfacing, projection, Materials

(The other "LW v B workflows topic seemed to be getting too long to be useful for actual tips versus just chatting.)

I’m having a heck of a time with Blender’s methods for ‘decals’ – a lot of the solutions I’ve been suggested seem overly convoluted, and are not actually Material solutions, using instead extraneous geometry to shrink wrap a ‘card’ onto the target mesh.

I’m looking for a solution that is more like LW’s projection methods, that does not use extra geometry AND is not tied to UV mapping, since part of the goal is to be scoot the decal around with no regard to UV mapping, which would be excessively ‘sticky’. In LW terms, just a simple axis projection would be fine, but among the mountain of hits for “blender decals” I’ve yet to find a similarly simple solution.


(more info, for clarity) This is for a super-hero logo, to go on their chest. I’d like to be able to size & rotate it at will, and have it all integral to the Material.

Flat projection with an empty tracking the mid-point of the mesh could work.

See attached blend.

The only issue I couldn’t solve is that the decal is projected on both sides of the mesh, but that may not be an issue for you. Perhaps someone else knows how to get rid of the second projected decal?

Grab the empty to reposition and scale the decal, and use the mapping node to rotate the Z axis to control decal rotation.

Allows for much freedom.

Eevee doesn’t seem to like this approach much and the surface goes haywire (why I do not know: perhaps someone could chime in as to why?). Cycles works.

decals.blend (1.6 MB)

I’m CSI’ing this now, but: do you know what’s going on here with this “reversed normals” look? (The normals are not reversed.)

THANKS. I continue to be baffled by what should be quite simple.

As I mentioned, it only works as expected in Cycles. Eevee doesn’t like this method much, I think :wink: Seems like a bug to me.

Ugh. This (is one of the many things) I hate about Blender: ENDLESS “gotchas”.

Thanks man.

Here is a new version that works in Eevee and Cycles. I have no idea what happened with that other object, but somehow I ruined the normals along the way while experimenting. It works fine now in Eevee. Operator error! Not a bug.

This version avoids the double stamp by introducing a second material slot which is limited to a face set. And the empty is parented to the teapot which keeps the decal in place when the teapot is moved around.

Just make sure to have two identical shaders to create a seamless overlap.

decalsteapot.blend (1.1 MB)

Buy the decal machine addon, it’s just so much faster and easier to do decals with it. I use it every day at work to put branding on products.

Just a quick comment: it wasn’t the mesh, because I substituted a sphere for Suzanne (in the same ‘Object’) and got similar-ish issues with that. So, I think it must have been SOME (but what???) attribute of the Material.


On the single sided: 1) trying to remember how we stopped through-projection in LW , 2) perhaps there’s a nodal way to limit it to normals facing the correct way, 3) or hand-crafted falloff in relation to the Reference Object.

You can just put a gradient texture based on the position of a null, like this.

Better screenshot of the nodes.