Placing a small decal with Blender & Octane

[voon]

Ok, this is probably a laughable question to the pros, but I'm very confused with it Still learning. Advanced UV mapping and texture handling is something that ties my brain into a know at the moment.

Imagine a simple square face .. side of a cube for instance. I want it to be metal. So I cerate a material in blender, set up my nodes, add metal textures, normal maps etc. I unwrap the face and go to Blenders image/UV editor and scale/move the UV vertices around till my face shows the metal the way I want.

But now comes the thing I don't understand: I would like to add a few decals to this metal face. Say a little radition warning sign on the lower left corner, some manufacturer symbol on the top, a few saftey instructions etc ... about 10 different decals.

How do I do this? How can I place little decals at various places of a face? Do I have to simply create 10 extra planes and size them to the size of the decal I want, create a material with the decal texture and its own UV map, picking the right part of the decal texture (one texture holding all the decals)? Then I would end up with a lot of materials ... sounds dodgy?

[FooZe]

How do I do this? How can I place little decals at various places of a face? Do I have to simply create 10 extra planes and size them to the size of the decal I want, create a material with the decal texture and its own UV map, picking the right part of the decal texture (one texture holding all the decals)? Then I would end up with a lot of materials ... sounds dodgy?

Hi Voon,
Yes, this would be the method to use in octane. I think creating a new texture with all the decals on it is the best/simplest option (although creating individual planes will probably work, it might just end up being more work) and just create a single plane for this texture to sit on that is slightly offset from the metal. You will also need a greyscale mask to use for the opacity input of the decal planes material so the plane is completely see-through where it needs to be (wherever the decal isn't).

[Jaberwocky]

Voon

I posted a decal placement solution online

please see:

http://render.otoy.com/forum/viewtopic.php?f=21&t=41226

Cheers

Jaba

[voon]

Hm, for that you can just use a TIFF with Alpha channel and then feed the same TIFF using alphatexture nodes into the opacity of the material shader, no? This method is a bit bad, though .... the extra planes may work for flat areas, but it probably gets a bit annoying with curvy areas and you always have to rearrange, redo when the mesh below it changes etc.

Can you not define several UV maps and assign them to different textures? That would only work for textures with one single decal though, you'd just scale up the UV map till it's bigger than the image texture and then move it around until the texture is where you want it .... but that doesn't work with these nice decal textures, where you don't use the UV map to position the decal as just described.

@Jabberwocky

Thanks will have a look

@Fooze

Can Octane not handle several UV maps assigned to specifix textures? I noticed I can do this in Blender Cycles: Just create a mixtexture with the two involved textures, then create two "Attribute nodes" (whatever they are in cycles) and feed them into the vector input of the Cycles texture nodes .... then I put the name of the first UV map into the first attribute node, and the name of the second UV map into the second Attribute node ... that results in the desired effect. At least to just mix two textures with selectable positions.

It still doesn't let me use a nice single texture containing all decals, though, since the oversized UV map is ued to "place" the decal.

PS: Wish texture/UV handling was simpler and more intuitive

[FooZe]

@Fooze

Can Octane not handle several UV maps assigned to specifix textures? I noticed I can do this in Blender Cycles: Just create a mixtexture with the two involved textures, then create two "Attribute nodes" (whatever they are in cycles) and feed them into the vector input of the Cycles texture nodes .... then I put the name of the first UV map into the first attribute node, and the name of the second UV map into the second Attribute node ... that results in the desired effect. At least to just mix two textures with selectable positions.

It still doesn't let me use a nice single texture containing all decals, though, since the oversized UV map is ued to "place" the decal.

PS: Wish texture/UV handling was simpler and more intuitive

No sorry, octane can't handle multiple UV maps, have you voted for it here: http://render.otoy.com/forum/viewtopic.php?f=9&t=37045 ?

[voon]

Heya Fooze

Yes ... did vote ... but honestly, I don't see my vote changing much there and it's been quite stable as it is I wonder why it has such low priority. I guess many people do architectural 3D where you often have just one material and one texture ... and a picture is already its own object .... if you do spaceships, aircraft etc, the need for decals is very high.... sigh.