PNG label on clear glass - how?

[arail]

I use a procedure by James Darknell to place a PNG label on a clear glass in modo (like a label on a bottle).
V-Ray sees the label but renders it as dim grey (the original is red) in a rectangle.
Any thoughts on how to make this work?
Thanks for any input you can give.

[kubbek]

I don't know how do you approach it but I tried using png image with alpha as a group mask and it seems not to work correctly in V-Ray for Modo.
You could make a black and white copy of your label and use it as a group mask.

[vladimir.nedev]

The most likely reason for this wrong behavior is that we don't support the "Alpha Only" option for the "Alpha channel" of the "Image map" texture.
I've fixed this for the nightly build from 2015-04-21, as well as for the 3.00.07 open beta build.

I don't know how do you approach it but I tried using png image with alpha as a group mask and it seems not to work correctly in V-Ray for Modo.
You could make a black and white copy of your label and use it as a group mask.

In this case, are you using "Alpha Only" for the "Image map" ? The original tutorial from James Darknell uses this option for the group mask effect.

One more caveat, V-Ray can blend only channels that can be textured in MODO's material, i.e. the ones that show as texture effects.
The rest of the channels are taken from the top-most material. One of these channels is the refractive index, so it is best to set
the refractive index be the same for all material items that you are blending. I am attaching a sample scene that should render correctly with the 2015-04-21 nightly build.



label_on_glass.zip

Greetings,
Vladimir Nedev

[arail]

Thanks for the replies. I'm gone today. Will get back to this tonight and try and sort it out based on your information.
By the way - totally off topic - I'm getting spectacular renders out of modo V-Ray. And I know next to nothing about rendering.