Using Opacity with Flat Shaders in Arnold

[Anonymous]

I want to use an alpha map (just black and white) to control cut out opacity on a flat shader in Arnold.  I can easily attach the texture I made to Opacity in an AiStandard and it works.  But what if I want to use a AiFlat or an AiUtility set to flat color?  There doesn't appear to be an opacity channel in these shaders.  (The reason I want to use a flat shader is because there are no lights in this file and all the textures have the shadows, etc, painted into them.) I've included a file of my current render - you can see that some objects are just painted textures applied to a plane, and I'd like to trim these edges away with a texture file.

[sean.heasley]

Hi @Anonymous unfortunately you're right and the opacity mask does not work on the flat shaders. However have you tried using the Standard shader and just tweaking the spec and metallic settings so that only the light from the texture will show? That may be your best bet.

[Anonymous · Accepted solution]

I received some good advice from Arvid Schneider (great tutorials on Youtube) for this problem.  I didn't want to use any lights at all in this project, instead the color of the textures I've painted should be sufficient.  Since the matte attributes on the Standard shader wouldn't work from me, Schneider suggested using the emission channel for the color texture file and turn off the diffuse in the render settings in the polygonal objects's shape node.  Then I plugged the alpha texture into the opacity channel and the shader worked as expected.

[Ninurta]

It was 2018
there is still no transparency in maya in flat shaders
such a simple and elementary thing!
what's the problem, autodesk?

[mspeer]

Hi!

Transparency is not simple, on the contrary, it's a complex render feature.

If you want a flat shader with more options use one of the other shaders and restrict the look to a flat view, or even better (faster and more flexible), do this later in compositing.

[Ninurta13]

it is almost 2024!

but it is sill missing...

autodesk autodesk...