Label on Glass

ebergerly

I have an OBJ mesh that I've applied an Iray glass shader to. Looks great. 

Now I want to add a label to the glass. There's a nice UV map I made, and I made a label image (PNG) with a transparency behind the label text. 

So how do I make the label show up on the glass? I tried the Layered Image Editor (as best as I can recall...), but that didn't do the trick (I tried all of the blending types). 

It does show up in the Shaded Textured preview, but the Iray preview just shows the glass.

Oh, and I tried adding an Iray Decal node, but that just gave me a black patch over half of the glass body. I tried rotating and moving it but no luck. 

Anyone? Thanks. 

Richard Haseltine

Does the Iray glass sahder even take maps? I would be inclined to do something like this with a Geoemtry Shell, since the material requirements are very different - Create>New Geometry Shell and adjust the offset value in the Parameters pane to reflect the thickness of the label.

ebergerly

Aha !!! I think you've got it. We're talking two completely different layered materials with completely different properties, not just layered images. I was over simplifying....

Thanks. 

ebergerly

For anyone who might be interested, Richard's suggestion is the best approach, IMO. What I did in my mesh editing software is select the faces on the bottle where I want the label to go, duplicate them into a separate label object, assign a separate material to the label, then Join the label and bottle objects and export. That way you can get fancy and give the label some thickness, use the label image alpha channel to make a label of just text, etc. 

Thanks.  

lwaves

I have another aproach which I prefer. This way has the textures applied to the glass and not to a shell that sits 'slightly' above the surface. You'll need three texture maps, the standard diffuse map, a black/white map where white is the areas you want to see (i.e. the decal part) which I'll call BW1 for this example, and an invert of that map where the black is the decal part you want to see, which I'll call BW2 for this. One of those last two maps will be exactly the same as a transparenvy map, with the other one being the inverse of it, if that helps.

Place the diffuse map in 'Base Colour' (this might not be needed). Place BW1 in 'Diffuse Overlay Weight' with a value of 1.0 and this will open up other options. Place another diffuse map in 'Diffuse Overlay Colour' with a full white colour value. Place BW2 in 'Refraction Weight' with a value of 1.0.

That should be it, although tinkering with values may be needed depending on your exact shader. It doesn't show up in the textured shaded preview but it does in the Iray preview. This method allowed me to add decals to a transparent black shader on the windscreen of a Lego Buggati Chiron, so it should work for other glass too. :-)