As you can see, with the falloff technique it works in the viewport and render. The drawback of this technique is to be limited to just 1 object. So Would be lovely if this technique could work with Corona Distance.
Any chance of this being solved before the 4.0 final release?
I would say the main drawback is, that the falloff map does not respect geometry of the distance object so that you are limited to a radial/spherical area. You cannot cut straight lines with it. Have you tried using the distance map in the shader opacity slot instead? This may be a better workaround.
In fact I will not use any of these workarounds because I wanna teach this technique (with distance) in my Corona Course because I know it is way better for this process. I just said one of the drawbacks, but yes,falloff It will limit this features as well.
About the distance + Opacity, I tried but it increased the rendertime a lot (as expected by using opacity)
Anyways, I can wait the bugfix in the next versions. Thanks a lot for the tip.