How to render alpha channel?


Alpha channel is available in Corona VFB's dropdown list by default. To additionally render alpha channel element, go to Render Setup > Render Elements and click "Add...". Pick "CShading_Alpha" and click OK. To change each material's alpha channel contribution, in Corona Material go to "Advanced options" > Alpha channel.



For a list of all render elements available in Corona, see: What render elements are there?

To make objects invisible in other masking elements, see: How to make an object invisible in masks?



Examples


1. Diffuse-only material


1.1. Beauty:



1.2. Alpha.
Red sphere:
Alpha mode = "Default"
Visible in masks = on



1.3. Alpha.
Red sphere:
Alpha mode = "Always transparent"
(in this case, when Alpha mode is set to "Always transparent", "Visibility in masks" is not relevant)



1.4. Alpha.
Red sphere:
Visible in masks = off
Alpha mode = "Default" or "Always solid"




2. Refractive material


2.1. Beauty:



2.2. Alpha.
Refractive sphere:
Alpha mode = "Default"
Visible in masks = on



2.3. Alpha.
Refractive sphere:
Alpha mode = "Always transparent"
(in this case, when Alpha mode is set to "Always transparent", "Visibility in masks" is not relevant)



2.4. Alpha.
Refractive sphere:
Alpha mode = "Always solid"
Visible in masks = on



2.5. Alpha.
Refractive sphere:
Visible in masks = off
Alpha mode = "Default"




3. Reflective material


3.1. Beauty:



3.2. Alpha.
Reflective sphere:
Alpha mode = "Default"
Visible in masks = on



3.3. Alpha.
Reflective sphere:
Alpha mode = "Always transparent"
(in this case, when Alpha mode is set to "Always transparent", "Visibility in masks" is not relevant)



3.4. Alpha.
Reflective sphere:
Visible in masks = off
Alpha mode = "Default" or "Always solid"