How do you use the Alpha channel of Vertex Colors?

[zeauro]

@slackbeard

I assume since there’s a way to edit alpha, there must be a way to use alpha?

Alpha channel of vertex color was a GSOC project in 2017.

GSoC 2017 : Vertex Painting Improvement

Hello everyone, I am Darshan Kadu, I am doing vertex painting improvement project during GSoC 2017. here is the link to the proposal https://wiki.blender.org/index.php/User:Darshan/GSoC2017/Proposal Link to my branch is --> https://developer.blender.org/diffusion/B/browse/soc-2017-vertex_paint/ I will be writing report every week --> https://wiki.blender.org/index.php/User:Darshan/GSoC2017/Reports I will require the help of blender artists and users to test the implemented features and also…

So, student made it work in a 2.7 UI, 2.7 viewport. But making it work with Cycles, was out of scope of his GSOC.
Then, it was merged into 2.8 but work, to make it possible to render it, was constantly postponed as a less priority task among huge amount of tasks relative to 2.8.
So, painting alpha is there in 2.8 but you can’t see it or render it.

On the contrary, if you use a recent build of 2.7 branch, you can see vertex alpha painting effect in viewport and you can render it with Blender Internal.