Alpha Texture Issue

[rdcontent]

I'm working on a project at the moment which requires a lot of textures on top of each other. Unfortunately I cannot post the project or a screenshot of it since what we're working on is confidential - So I'll do my best to describe the issue instead.

Most textures are working well, except I'm having a problem with one of them. I'll give you a run down of the texture layers:

On the base I have a glossy white material. On top of that I have another blue glossy material on specific faces using a selection tag. Then on top of that I'm adding a texture image with an alpha channel - for some reason the alpha is not working or showing the blue glossy material below it. I have put the image on a plane with the white glossy material underneath it and that works fine, but it's not working on top of this mesh for some reason and I'm not sure why.

Any help would be greatly appreciated.

Thank you .

[bepeg4d]

Hi,
quite difficult without images, but from your description, it seems that you are not using mix materials, but the stacking materials option instead.
My suggestion is to use the alpha image in the amount of a mix material with the blue glossy, and whatever you want to mix.
Hope it helps,
ciao beppe

[rdcontent]

Hi Bepeg,

Yes - sorry about the no images - Maybe I can recreate it on another mesh if I can't figure out the problem through trying!

The mix materials worked great for the part where it had a single colour underneath - though for a part where there are intersecting colours of red, blue and darker blue the mix material is not working.

I've also worked out that whatever poly faces the selection tag has - the alpha won't work through them?

[rdcontent]

OK I've recreated a scene that encounters the same problem with the alpha of the image not working.

Please see here - *Link Removed*

Any help would be warmly appreciated - Thanks in advance.

[niestudio]

It looks like you're overriding the previous selection tag with the next selection tag.
Could you just add them w/o the selection tags using custom alpha channels on each one?

[rdcontent]

Hey Niestudio,

Thanks for helping out! The selection tags are very specific to the mesh and would be almost impossible to create an alpha for them. Is there another solution to the problem that you can think of? I'm pretty stumped at the moment!

[rdcontent]

OK, my workaround for this problem was to duplicate the mesh and apply just the alpha logo texture onto the object. I inverted the selection tag selection and deleted these polys so just to be left with the mesh where the logo is sitting. Then moved the new logo object 0.01cm in Z outwards from the previous mesh as if to be seperate ontop of it.

Thanks for both of your help!

Happy rendering -