Using an image as "decal"

[Tyger2]

I want to be able to use an image on just one part of a model, in addition to its other textures. In my case I was using it as a height map, but the principal should be the same for using it as a diffuse color or any other map.

Came across this issue when adding the skull engraving onto my pirate sword for this week’s collab.

I got the idea from @FedPete’s pen and ink set, and I saw @NP5 you may have done something similar in adding the carving to your pirate chest. I’m curious how you guys approached this.

This is the solution I came up with:

• get a white and black image of whatever you want to be engraved
• send that to the height value of a bump vector node
• send the bump normal output to the normal input of the bump vector for the rest of your material. This seems to add them together

This is where it gets tricky. How do you get it to be just on the one spot on the model, and not tiled everywhere? I know I probably need to use a UV map, but it seems like a waste to make a big image with engraving small in the corner.

So I ended up using this weird unwrap. The square that’s selected in the left of the image is just that face where I wanted the image to be. I scaled up the UV for that face, and scaled all rest of the blade off to the side where it was just black. This worked, but it doesn’t seem like the most elegant solution.

Did you guys (or anyone else) do something similar? Do you know a better way to do this?

[FedPete]

I would do it on the same manner as you do.
Create multiple UV maps for special usages…
But, my experience is that when the node set is starting to get complex.
My computer slows down. Then I go for the blunt version.
Create big maps in combination of a baking solution (not a fan of only for animation / game).
Or abort the idea. Or change a different composition.

[NP5]

I did it the stupid way. Used the image as a reference and trace sculpted the lines in. Though my intent was deeper than a shallow engraving, a wood carved marking. Would have been easier to model it and boolean it out.

[Tyger2]

Thanks for the response, guys!

@FedPete

in combination of a baking solution

I haven’t done much baking. But I saw a video once where a person baked the detail of a very high-poly sculpted model onto a low poly one. I think the detail was applied as normals/bump? I don’t know, but it seemed cool.

@FedPete

Or abort the idea.

I think this–and overall efficiency in general–is something I really need to work on. I know I’m still learning, so I justify getting lost in the weeds as exploring new skills, but maybe I’m forming bad habits by doing that.

@NP5

the stupid way

Well there are no right or wrong ways, right? I thought it worked as a carving but maybe the result was not what you envisioned.

@NP5

Would have been easier to model it and boolean it out.

Ooh yeah of course! I didn’t even think of that. This might be the simplest solution.

[FedPete]

@Tyger2

I haven’t done much baking. But I saw a video once where a person baked the detail of a very high-poly sculpted model onto a low poly one. I think the detail was applied as normals/bump? I don’t know, but it seemed cool.

It think there are 6 or 7 mathematical types (as bitmap) to describe the surface (texture / material).
And I think they can all be baked.

• Diffuse
• Glossy / specular
• Normal
• Bump
• Displacement
• Z-map

[Tyger2]

@Tyger2

How do you get it to be just on the one spot on the model, and not tiled everywhere?

Maybe you guys already knew but I just discovered this:

Setting it to “clip” solves the tiling issue. I explored this a bit more applying the logo to the football I made yesterday.

I think the Multiple UV Maps solution is the way to go.

[Wordofcurse]

Cool sword!

If I am understanding your issue properly - perhaps you could use weight painting or vertex colors and trace out where you want the ‘decal’ to be? Or where you don’t want it to be. I think I would use vertex colors for this and attach a vertex color node into my node system to specify specifically where the texture height would be to have my ‘decal’ depressed into the mesh, or rather, have it’s height be unaffected by texturing… I would have to test this out before being sure if it would work… but boolean is a good suggestion as well though! Just remember booleans tend to cause issues with bevels modifiers.

[NP5]

No never thought of that. Handy option. Get so used to just adding the node for the image and ignoring its options.