Render only mask - aplha issue

[Alexandre Besson]

Hi,

I noticed apha mask issue when render only mask is checked, alpha is black with glass material (visible in mask or not)

[TomG]

Yes, at the moment alpha is only calculated if actual rendering is done - developers can say for sure, but I think this is because things like opacity, refraction, etc. need to be calculated in order to come up with the alpha, and those are rendering rather than masking items, so they need a full render to be happening.

[Vlad_the_rant]

Currently, this is expected behavior as Tom has stated above. It may change in a future version of Corona, however, so stay tuned!